AGE AND GROWTH THROUGH SCALE, OTOLITH, MATURATION AND FECUNDITY OF SOME COMMON SNAPPERS LUTJANUS LUTJANUS AND L. JOHNII (FAMILY LUTJANIDAE) IN PAKISTANI WATERS WITH SPECIAL REFERENCE OF DISTRIBUTION ON SINDH COAST.
MUHAMMAD ASIM
DEPARTMENT OF ZOOLOGY UNIVERSITY OF KARACHI Karachi-75270 CERTIFICATE
UNIVERSITY OF KARACHI FACULTY OF SCIENCE
This thesis entitled “AGE AND GROWTH THROUGH SCALE, OTOLITH, MATURATION AND FECUNDITY OF COMMON SNAPPERS LUTJANUS LUTJANUS AND LUTJANUS JOHNII (FAMILY LUTJANIDAE) IN PAKISTANI WATERS WITH SPECIAL REFERENCE TO DISTRIBUTION ON SINDH COAST” .Submitted by Muhammad Asim is accepted by the Department of Zoology, University of Karachi, as satisfying the thesis requirement for the degree of Doctor of Philosophy (Ph.D.) in Zoology.
Supervisor ______Prof. Dr. Habib-ul-Hassan Department of Zoology University of Karachi.
Co- supervisor ______
Prof. Dr. M. Zaheer Khan Department of Zoology University of Karachi.
This Dissertation
is dedicated to my wife, beautiful son
Muhammad Hamdan Asim my sisters Mrs.
Nafees Subohi (Late) and Ms Anees Roohi who
always wishes and prays for my success.
ACKNOWLEDGMENT
My deep reverence goes to Almighty Allah, my supreme, who enabled me to complete the present work.
I thankful my respected supervisor Prof.Dr. Habib-ul-Hassan and co-supervisor Prof. Dr. Muahmmad Zaheer Khan for their support, guidance and encouragement.
I would like to thanks Dr. Constantine Stamatppoulos (Fisheries Resources Monitoring and Assessment Lamans) ICLARM for the guidance to determine the age and growth by von- Bertalanffy growth parameters by VONBIT software tool.
I am also acknowledged to Respected Muhammad Moazzam (Ex. Director General, Marine Fisheries Department Government of Pakistan and present Technical Advisor (Marine Fisheries) WWF-Pakistan for his guidance and encouragements.
I would like to thanks Dr. Tufail Muhammad Jokhio Dean of Chemical Process Engineering (CPE), NED University, Karachi Pakistan for their help for otolith section cutting thus making it possible to determine the age.
I would like to thanks Mr Waheed Ahemd, Additional Secretary, Livestock and Fisheries Department, Government of Sindh for their Guidance, encouragements. Very much thanks to Mr.Ghulam Mehar, Director General Fisheries, Government of Sindh for moral support.
I am also grateful to Dr. Pirzada Jamal Siddique for allowing me to use Lab at Centre of Excellence in Marine Biology (Centre of Excellence in Marine Biology), University of Karachi.
I would like to thank Mr. Muhammad Tariq Hanif (Fisheries Researcher) from Marine Fisheries Department, Government of Pakistan, for guidance, encouragement and suggestions about working in R-Statistical software and graphical representations.
I am very much thankful to my Dearest friend Dr. Syed Salahuddin Qadri, Assistant Professor, Government Jamia Millia Degree College, Karachi, and my colleagues Muahammad Arif Shakir, Mr Aijaz Ahmed Memon, Assistant Director Fisheries, Syed Nasir Ali Naqvi, Mr Muhammad Ashraf (Photographer) Sindh Fisheries Department, Government of Sindh and Mr Sharjeel Parvez Butt for their unconditional support.
I am very much thankful to all fishermen who supported me in collection of samples from boat collections and fish markets for this research work.
I want to express my deepest gratitude to all, those help out and support me for completion of this work specially my wife and cute son Muhammad Hamdan Asim.
TABLES OF CONTENT
Description Page No
KHULASA (URDU) ABSTRACT 1
1 INTRODUCTION 3
1.1 Classification 6 1.2 Descriptive characters of family Lutjanidae 7 1.3 Lutjanus lutjanus (Bloch 1790) 8 1.4 Lutjanus johnii (Bloch 1792) 9 1.5 Distinguish Characters 9 1.6 key to species of family Lutjanidae 10 1.7 Determination of age and growth 20 1.8 Status of Lutjanids in Pakistan 20 1.9 Objectives of present study 23 2 REVIEW OF LITERATURE
2.1 Taxonomy status and classification of Lutjanidae 24 2.1.1 General Taxonomy status of Lutjanidae 27 2.1.2 Classification of Lutjanidae 29 2.2. Characters and species of Lutjanidae 32 2.2.1 Characters of Lutjanidae 32 2.3. Reproductive Biology 36 2.3.1 Gonad maturation stages 43 2.3.2 Gonad somatic Index (GSI) 45 2.3.3 Size at Sexual maturity 47 2.3.4. Spawning seasons 52 2.3.5. Fecundity 55 2.4. Fishery Information 59 2.4.1. Total length and body weight relationship 61 2.4.2. Catch per Unit effect 64 2.4.3. Sex Ratio 66 2.5. Age and growth studies 68 2.5.1. Based on fish otolith 72 2.5.2 Based on fish scale 77 2.6. Population dynamic Parameters 79 2.6.1. Growth 83 2.6.2 Mortality 85 2.6.3 Recruitment 87 2.6.4. Age 88
3 MATERIAL AND METHODS 89
3.1. Specimen collection and Sampling Sites 89 3.2. Identifications and measurement 91 3.3. Size class 91 3.4. Macroscopic observations 92 3.5. Reproductive biology 92 3.5.1. Analysis of gonads 92 3.5.2 Classification of maturity stages based on macroscopic 93 analysis 3.5.3 Gonad somatic Index (GSI) 94 3.5.4.Estimation of L 50% Sexual Maturity 95 3.5.5. Fecundity 95 3.6 Otolith 96 3.7 Validation of age 98 3.8 Analysis of length frequency data 98 3.9. Length-weight relationship analysis 99 3.10. Calculated length weight data 100 3.11 Estimation of age and growth 101 3.11.1 Method for fitting von Bertalanffy growth parameters by 101 linear regression analysis (Constantine Stamatopoulos and Caddy (1989) 3.11.2 Estimation of age and growth by VBGF curve through 102 “R” statistical software 3.11.3 Linear regressions by Microsoft Excel Program. 102 3.12. Scale observations 102 3.13. Population dynamics (FiSAT-II,1.2.2 VER FAO, ICLARM) 104 3.13.1. ELEFAN 1 routine of FAO- ICLARM Stock Assessment 104 Tool FiSAT II software 3.13.2.Von Bertalanffy growth curve 104 (FiSATII,1.2.2 version) 3.13.3.Shepherd’s method 105 3.13.4. Powell - Wetherall plot 105 3.13.5. Analysis of Growth increment data 106 3.13.5.1. Gulland & Holt plot (Gulland and Holt, 1959) 106 3.13.5.2. Munro’s method 106 3.13.5.3. Faben’s method 107 3.13.6. Mortality 107 3.13.6.1. Length converted catch curve 107 3.13.6.1.1 Jones & Van Zahlinge plot 108 3.13.6.1.2. Beverton and Holt model 108 3.13.6.1.3. Ault & Ehrardt method 108 3.13.6.2. Estimation of Natural Mortality rate (M) 109 3.13.6.2.1.Rikhter and Efanov’s method 109 3.13.6.2.2. Pauly Empirical Equation 109 3.13.7. Recruitment Patterns 109 3.13.8. Probability of Capture 110 3.13.9. Gill net selection 110 3.13.10. Virtual Population analysis (VPA) 110 3.13.11. Relative Biomass per recruitment (Beverton & Holt Y/R) 111 3.13.12. Estimation of Yield per recruitment and biomass per 112 recruitment. 3.13.13. Maximum length estimation (Lmax) 112 3.13.14. Growth performance indices 113 3.15. Distribution 113 3.16. Experimental Design 114
4 RESULTS Lutjanus lutjanus (Bloch 1790) 115
4.1 SIZE FREQUENCY DISTRIBUTION 116 4.1.1. Size frequency distribution for year 2005 116 4.1.2 Size frequency distribution for year 2006 116 4.1.3 Size frequency distribution for Year 2007 117 4.2. Analysis of Gonads 123 4.2.1 Macroscopic and Histological examination of gonads. 123 4.2.2. Monthly variation in maturity stages of Lutjanus lutjanus 129 4.3 Marginal increments Analysis (MIA) 133 4.4 Estimation of L 50% Sexual maturity 133 4.5 Oocytes size frequency distribution of Lutjanus lutjanus 135 during three years (2005-07) 4.6. Fecundity 137 4.7. Percentage frequency distribution of Lutjanus lutjanus (Male, 141 Female and Juveniles) 4.8 Length weight relationship 142 4.9 Linear regression analysis 144 4.9.1 Fish length VS Fish weight 158 4.9.2 Fish Length TL (cm) V/s Scale Size (mm) 158 4.10 Estimation of Age and growth 158 4.10.1 Otolith Morphology 158 4.10.2 Scale observations 160 4.10.3 Sectioned otolith Vs whole otolith 160 4.10.4. Otoliths Vs Scales 160 4.11 Age estimation of L. lutjanus 162 4.12 Determination of growth L. lutjanus 164 4.12.1 Method for fitting von Bertalanffy growth parameters by 164 linear regression analysis (Constantine Stamatppoulos, 2005) 4.12.2 Estimation of Age and Growth by von bit growth 173 equation in “R” statistical software. 4.12.3. Mean length and observed length 176 4.13. Estimation of Population dynamics (FiSAT-II,1.2.2 VER FAO, 180 ICLARM) 4.13.1 Estimation of population dynamics parameters for L. 180 lutjanus (all individuals) 2005. 4.13.2. Estimation of population dynamics parameters for L. 188 lutjanus (all individuals)2006. 4.13.3. Estimation of population dynamics parameters for L. 196 lutjanus (all individuals) 2007. 4.13.4. Estimation of population dynamics parameters for L. 204 lutjanus (all individuals) 2005-2007. 5 RESULTS Lutjanus johnii (Bloch, 1792) 220
5.1. Size frequency distribution 221 5.1.1. Size frequency distribution for year 2005 221 5.1.2. Size frequency distribution for year 2006 222 5.1.3. Size frequency distribution for year 2007 222 5.2. Analysis of Gonads 229
5.2.1. Macroscopic and Histological examination of gonads 229 5.2.2. Monthly variation in maturity stages of Lutjanus johnii 234 5.3 Marginal increments analysis (MIA) 238 5.4. Estimation of L 50% sexual maturity 238 5.5. Oocytes size frequency distribution of L. johnii during three 239 years (2005-07) 5.6. Fecundity 242 5.7. Percentage frequency distribution of Lutjanus johnii (male, 244 female and juvenile) 5.8. Length weight relationship 245 5.9. Linear regression analysis 256 5.9.1 Fish Length Vs Fish weight 261 5.9.2. Fish Length cm (TL) V/S Scale Size mm 261 5.10 Age and growth of Lutjanus johnii 261 5.10.1. Otolith morphology 261 5.10.2. Scale Observations 264 5.10.3. Sectioned otolith Vs whole otolith 264 5.10.4. Otoliths Vs Scales 264 5.11. Age determination of Lutjanus johnii 266 5 5.12. Determination of growth of Lutjanus johnii 269 5.12.1 Method for fitting Von Bertalanffy growth parameters by 270 Linear regression analysis ( C. Stamatopoulos and Caddy, 1987,2005) 5.12.2 Estimation of age by “R” statistical software. 279 5.12.3 Mean Length and observed length 281 5.13. Estimation of Population dynamics Parameters 285 5.13.1. Analysis of population dynamics parameters by length 285 frequency data of Lutjanus johnii whole data 2005 through Growth performance estimation by FiSAT-II.Version 2.2.1. 5.13.2. Analysis of population dynamics parameters by length 293 frequency data of Lutjanus johnii whole data 2006 through Growth performance estimation by FiSAT –II 5.13.3. Analysis of population dynamics parameters by length 300 frequency data of Lutjanus johnii whole data 2007 through Growth performance estimation by Fi SAT-II
5.13.4. Analysis of Population dynamics Parameters by Length 307 Frequency data of L. johnii for three years (2005-2007) through Growth performance estimation by Fi SAT-II.
5.15. Distribution of Lutjanus lutjanus and Lutjanus johnii 317
5.15.1. Discussion on distribution 320 6. Discussion 330
6.1 Lutjanus lutjanus 6.1. Gonadal Maturation 330 6.1.2. Spawning and estimation of fecundity 331 6.1.3. Scale and otolith 332 6.1.4. Marginal increment 332 6.1.5.Length at age analysis 333 6.1.6. Population dynamics parameters 334 6.2 Lutjanus johnii 338 6.2.1. Gonadal Maturation 338 6.2.2. Spawning and estimation of fecundity 339 6.2.3. Scale and otolith 341 6.2.4. Marginal increment analysis (MI) 341 6.2.5. Length at age analysis 342 7. CONCLUSION 346
8. REFERENCES 348
LIST OF FIGURES
Figure Description Page No No
1.1 Lutjanus johnii from Karachi Fish Harbor (7750 gm, TL 75 cm) 7 1.2 Lutjanus lutjanus (Bloch 1790), Bigeye Snapper, Hira, Kunla, Kunalcha, 8 Rosy Snapper 27 cm TL (Karachi Harbor 2007) 1.3 L.johnii (Bloch 1792) John’s Snapper, Mosses Perch, Hira, Kunla, 9 Kanalcha, 35 cm TL (caught during boat collection 2007) 1.4 Systamatics of Lutjanus sp A and B 19 3.1 Collection from Phitti creek (Korangi creek area) Karachi, East 89 3.2 Complete Map for collection sites 90 3.3 Cavity of cranium of Lutjanus Lutjanus, 27cm (TL) where otolith were 97 found.(A).Inner portion of head region of Lutjanus johnii 42cm (TL) dissected for otolith (B). 3.4 Work flow chart of present study 114
Results Lutjanus lutjanus (Bloch 1790)
4.1 Lutjanus lutjanus (Bloch 1790) 115 4.2 Size distribution of Lutjanus lutjanus collected from Karachi Fish Harbor 122 (Dec 2007), A-27 cm, B-17.2 cm, C-15.2 cm and D-12 cm TL 4.3 Macroscopic observation of gonads showing different maturity stages in 124 Lutjanus lutjanus (Stage-I to VIII) 4.4 (A).Histological section of Juvenile gonad of 7.5cm Lutjanus lutjanus 125 shows granulocytes (Gc) with stroma cells (S). (B).Histological section of immature ovary of Lutjanus lutjanus shows ovarian lamella (OL) and Previtellogenic acolytes (PVO). Scale bare is 100 µm. 4.5 Histological section of developing ovary of Lutjanus lutjanus shows 126 primary growth and oocytes (PGO) cortical alveolar oocyte (CAO). Scale bare is 100 µm. 4.6 Histological section of Lutjanus lutjanus nearly spent ovary contains 126 postovulatory follicles (POF) and late vitellogenic oocytes (VO) scale bare is 50 µm 4.7 Histological section of Late vitellogenic oocyte (LVO) and hydrated 127 oocytes (Hy) of mature female of Lutjanus lutjanus 26.4 cm TL. Scale bars are 100 µm 4.8 Photomicrographs of histological section of testis of L. lutjanus mature 127 male shows spermatogonia (SG), spermatides (St), spermatocytes (Sc) and spermatozoa (Sp). Scale bare is 100 µm. 4.9 (A) Functional male caught during peak season showed different stages of 128 different stages of spermatogenesis Spermatocytes (Sc), spermatids (St) and spermatozoa (Sp). Scale bars E= 100 µm, F= 50 µm. (B)Photomicrographs of histological section of testis of L. lutjanus maturing male show spermatogonia (SG) and spermatocytes (Sc). Scale bare is 200 µm. 4.10 Whole otolith of Lutjanus lutjanus Juvenile scale bar is 2 mm. 158 4.11 Whole otolith of Lutjanus lutjanus three years old. Scale bar is 2 mm 159 4.12 Whole otolith of L. lutjanus 5 year old individual. Scale bar is 2 mm 159 4.13 Magnified photographs of Lutjanus lutjanus scales show different 161 numbers of growth zones. i: 9.5 cm TL, ii: 17cm TL, iii: 20cm TL, vi: 22.5cm TL, v: 24cm TL and 27cm TL. Scale bar in all is equal to 2 mm. 4.14 Transverse sections of otolith of Lutjanus lutjanus, black dots shows 162 different opaque growth zones, scale bar is 2mm 4.15 Transverse section of otolith of Lutjanus lutjanus black dots shows 163 different opaque growth zones, scale bar is 2mm 4.16 Length frequency and fitted Von Bertalanffy growth curve of L. lutjanus 180 (all individuals) 2005. 4.17 Estimation of K for A. intermedius by emploing ELEFAN-1 of L.lutjanus 181 (all individuals) 2005. 4.18 Estimation of K by emploing Shepherd’s method for L. lutjanus (all 181 individuals) 2005 4.19 Powell –Wetherall plot for L. lutjanus (all individuals) 2005 182 4.20 Gulland and Holt Plot. For L. lutjanus (all individuals) 2005 182 4.21 Munro’s plot based on (Munro 1982) L. lutjanus (all individuals) 2005 182 4.22 Length converted catch curve for L .lutjanus (all individuals) 2005, 183 darkened full dots represent the points used in calculating through least square linear regression and the open dots represent the points either not fully recruited. 4.23 Length converted catch curve for L .lutjanus (all individuals) 2005, for 183 estimation of total mortality (Z) 4.24 Recruitment pattern of L. lutjanus (all individuals) 2005 185 4.25 Probability of capture of L. lutjanus (combined) 2005 by gill net 186 4.26 Length based virtual population analysis L. lutjanus (combined) 2005. 186 4.27 (A).Yield isopleths /Recruit analysis (Knife-edge selection) (B). Relative 186 yield-per-recruit and for L. lutjanus (all individuals) 2005 4.28 Predicted maximum length of L. lutjanus (all individuals) 2005, based on 187 extreme value theory (Formation et al., 1991). 4.29 Length frequency and fitted Von Bertalanffy growth curve. L. lutjanus 188 (whole data) 2006 4.30 Estimation of K for A. intermedius by emplying ELEFAN-1 of L. lutjanus 189 (all individuals) 2006. 4.31 Estimation of K by emplying Shepherd’s method for L.lutjanus (all 189 individuals) 2006 4.32 Powell –Wetherall plot for L. lutjanus (all individuals) 2006. 189 4.33 Gulland and Holt Plot. for L. lutjanus (all individuals) 2006 190 4.34 Munro’s plot based on (Munro 1982) L. lutjanus (all individuals) 2006 190 4.35 Length converted catch curve for L. lutjanus (all individuals) 2005 191 4.36 Jones and van Zallinge plot for L. lutjanus (all individuals) 2006, for 191 estimation of total mortality (Z) of L. lutjanus (all individuals) 2006 4.37 Recruitment pattern of L. lutjanus (all individuals) 2006 193 4.38 Probability of capture of L. lutjanus (all individuals) 2006 by gill net. 194 4.39 Length based virtual population analysis L. lutjanus (all individuals) 2006 194 4.40 (A) Yield isopleths /Recruit analysis (Knife-edge selection) (B). Relative 194 yield-per-recruit and E=1.0 and Lo/Lo biomass-per recruit for L. lutjanus (all individuals) 2006. 4.41 Predicted maximum length of L. lutjanus (all individuals) 2006, based on 195 extreme value theory (Formation et al., 1991). 4.42 Lutjanus lutajanus, length frequency and fitted Von Bertalanffy growth 196 curve.(all individuals) 2007 4.43 Estimation of K for A. intermedius by emploing ELEFAN-1 of L.lutjanus 197 (all individuals) 2007. 4.44 Estimation of K by emploing Shepherd’s method for L.lutjanus (all 197 individuals) 2007 4.45 Powell –Wetherall plot for L. lutjanus (all individuals) 2007 197 4.46 Gulland and Holt Plot for Lutjanus lutjanus (all individuals) 2007. 198 4.47 Munro’s plot based on (Munro 1982) for Lutjanus lutjanus 2007. 198 4.48 Length converted catch curve for L. lutjanus (all individuals) 2007 199 4.49 Length converted catch curve for L. lutjanus (all individuals) 2007, for 199 estimation of total mortality (Z). 4.50 Recruitment pattern of Lutjanus lutjanus (combined) 2007 201 4.51 Probability of capture of L. lutjanus (all individuals) 2007 by gill net. 201 4.52 Length based virtual population analysis L. lutjanus (all individuals) 201 2007. 4.53 Yield isopleths /Recruit analysis (Knife-edge selection) for L lutjanus (all 202 individuals) 2007. 4.54 Relative yield-per-recruit and E=1.0 and Lo/Lo biomass-per recruit for L. 202 lutjanus (all individuals) 2007 4.55 Predicted maximum length of L. lutjanus (combined) 2007, based on 203 extreme value theory (Formation et al., 1991). 4.56 L. lutajanus whole data (all individuals) three years,2005-2007 , length 204 frequency and fitted Von Bertalanffy growth curve. 4.57 Estimation of K for A. intermedius by emploing ELEFAN-1 of L.lutjanus 205 (all individuals) 2005-2007 4.58 Estimation of K by emploing Shepherd’s method for (all individuals) 205 2005-2007. 4.59 Powell –Wetherall plot for L. lutjanus (all individuals) 2005-2007 206 4.60 Gulland and Holt Plot. For L .lutjanus whole data three years (all 207 individuals) 2005-2007. 4.61 Munro’s plot based on (Munro 1982) L. lutjanus whole data three years 207 (all individuals) 2005-2007 4.62 Length converted catch curve for L. lutjanus (all individuals) 2005-2007 208 4.63 Jones and Van Zalling plot for estimation of total mortality (Z) of 208 L. lutjanus, (all individuals) 2005-2007 4.64 Recruitment pattern of L. lutjanus (all individuals) 2005-2007 209 4.65 Probability of capture of L. lutjanus (all individuals) 2005-2007. 210 4.66 Length based virtual population analysis L. lutjanus whole data three 210 years (2005-2007) 4.67 Yield isopleths /Recruit analysis (Knife-edge selection) for L. lutjanus 211 (all individuals) 2005-2007. 4.68 Relative yield-per-recruit and E=1.0 and L0/L0 biomass-per recruit for 211 L. lutjanus (all individuals) 2005-2007. 4.69 Predicted maximum length of L. lutjanus (all individuals) whole data 212 2005-2007.
RESULTS LUTJANUS JOHNII ( Bloch 1792)
5.1 Lutjanus johnii (Bloch 1792) 220 5.2 Size distribution of Lutjanus johnii collected from Karachi Fish Harbor 229 (2005-2007), A-8.5 cm,B-12 cm,C-14.5 cm and D-16 cm TL 5.3 Macroscopic observation of gonads showing different maturity stages in 230 Lutjanus johnii (Stage-I to VI). 5.4 Histological section of immature ovary of Lutjanus johnii shows ovarian 231 lamella (OL) and Previtellogenic acolytes (PVO). Scale bare is 100 µm. 5.5 Histological section of developing ovary of Lutjanus johnii shows 231 primary growth and oocytes (PGO) cortical alveolar oocyte (CAO). Scale bare is 100 µm. 5.6 Histological section of fully mature ovary of Lutjanus johnii shows late 232 vitellogenic oocyte (LVO), yolk granule (YG) and zona radiate (ZR). Scale bare is 100 µm. 5.7 Histological section of nearly spent ovary contains postovulatory follicles 232 (POF) and late vitellogenic oocyte (VO) Scale bare is 50 µm 5.8 Photomicrographs of histological section of testis of L. johnii immature 233 phase show lumen of lobule (Lu), spermatogonia (SG). Scale bare 20 µm 5.9 Photomicrographs of histological section of testis of L. johnii mature male 233 shows spermatogonia (SG), spermatides (St), spermatocytes (Sc) and spermatozoa (Sp). Scale bare is 100 µm 5.10 Photomicrographs of histological section of testis of L. johnii maturing 234 male show spermatogonia(SG) and spermatocytes (Sc)Scale bare 200µm 5.11 Whole otoliths of Lutjanus johnii 12.5 (TL cm) 261 5.12 Whole otoliths of Lutjanus johnii 16.5 (TL cm) 262 5.13 Whole otoliths of Lutjanus johnii 20.5 (TL cm). 262 5.14 Whole otolith of Lutjanus johnii 30.5 (TL cm) 262 5.15 Whole otolith of Lutjanus johnii. 35.8 (TL cm) 263 5.16 Whole otolith of Lutjanus johnii 39.5 (TL cm) 263 5.17 Whole otolith of Lutjanus johnii 42 (TL cm) 263 5.18 Scale of Lutjanus johnii 24.5 cm TL arrows showing growth rings 264 5.19 Magnified photographs of L. johnii scales shows different numbers of 265 growth zones. I: 12cmTL,II:18.5 cm TL, iii:22.5cmTL, VI: 30.5 cm TL, V:40 cm TL and VI 50.5 cm TL. Scale bar in all is equal to 2 mm. 5.20 Sectioned otolith of Lutjanus johnii shows opaque zones (A&B) 266 “r”otolith radius (R); primordium (N), sulcus acoustics (SA), dorsal side (D) and ventral side (V).Scale bar is 2mm. 5.21 Sectioned otolith of Lutjanus johnii shows opaque zones “r” a, otolith 267 radius (R); primordium (N), sulcus acoustics (SA), dorsal side (D) and ventral side (V) black dots shows growth rings. Scale bar is 2mm. 5.22 F Sectioned otolith of L. johnii shows opaque zones otolith radius, sulcus 268 acoustics (SA), dorsal side (D) white dots shows growth rings. 5.23 Ven Bertalanffy Growth equetion 269 5.24 Length frequency distribution fitted Von Bertalanffy growth curve (2005) 285 Lutjanus johnii (all individuals) 2005. 5.25 Estimation of K for intermedius by emploing ELEFAN-1 of L. johnii (all 286 indviduals) 2005. 5.26 Estimation of K by emploing Shepherd’s method for L. johnii (all 286 individuals) 2005. 5.27 Powell–Wetherall plot from length frequency data of L. johnii (all 287 individuals) 2005 5.28 Gulland and Holt Plot. for all individuals data of L. johnii 2005 287 5.29 Munro’s plot based on (Munro 1982) for all individuals data of L johnii 287 2005 5.30 Length converted catch curve for L .johnii 2005 288 5.31 Jones / Von Zalinge plot Lutjanus johnii 288 5.32 Recruitment pattern of L. johnii (all individuals) 2005. 290 5.33 A. Probability of capture of L. johnii (all individuals) 2005 by trawl net, 290 (B) Probability of capture 2005 by gill net. 5.34 Length based virtual population analysis L johnii (all individuals) 2005. 291 5.35 Yield isopleths /Recruit analysis (Knife-edge selection) for L johnii (all 291 individuals) 2005. 5.36 Relative yield-per-recruit and biomass-per recruit for L johnii (all 291 individuals) 2005 5.37 Predicted maximum length of Lutjanus johnii (all individuals) 2005, 292 based of extreme value theory (Formacion et al.,1991) 5.38 Length frequency and fitted Von Bertalanffy growth curve for all 293 individuals population of L. johnii (2006). 5.39 Estimation of K for A. intermedius by emploing ELEFAN-1 of Ljohnii 294 (all individuals) 2005. 5.40 Estimation of K by emploing Shepherd’s method for L.johnii (all 294 individuals) 2005. 5.41 Powell –Wetherall plot for Lutjanus johnii (all individuals data) 2006 295 5.42 Length converted catch curve for Lutjanus johnii (combined ) 2006 296 5.43 Cumulative plot form of length converted catch curve, Jones and Von 296 Zalinge plot for Lutjanus johnii (mixed) 2006 5.44 Recruitment pattern of Lutjanus johnii (combined, whole data) 2006. 297 5.45 Probability of capture of L. johnii all individuals) 2006 by gill net. 298 5.46 Virtual population analysis of L. johnii (all individuals) 2006 298 5.47 Yield isopleths /Recruit analysis (Knife-edge selection) for L johnii (all 299 individuals) 2006. 5.48 Relative yield-per-recruit and E=1.0 and Lo/Lo biomass-per recruit 299 5.49 Predicted maximum length of L. johnii combined data (2006) based on 299 extreme value theory (Formation et al., 1991). 5.50 Length frequency L johnii (all individuals) 2007and fitted Von 300 Bertalanffy growth curve. 5.51 Estimation of K for intermedius by emploing ELEFAN-1 of L. johnii 301 (all individuals) 2007 5.52 Estimation of K by emploing Shepherd’s method for L. johnii (all 301 individuals) 2007. 5.53 Powell –Wetherall plot for Lutjanus johnii (all individuals) 2006 301 5.54 Gulland and Holt Plot for Lutjanus johnii (all individuals) 2007 302 5.55 Munro’s plot based on(Munro 1982) for L. johnii (all individuals) 2007 302 5.56 Length converted catch curve for L. johnii (all individuals) 2007 303 5.57 Cumulative plot of length converted catch curve L. johnii (all individuals) 303 2007. 5.58 Recruitment pattern of Lutjanus johnii (all individuals)2007 305 5.59 Probability of capture of L. johnii (all individuals) 2007 by gill net. 305 5.60 Length based virtual population analysis L. johnii (all individuals) 2007 305 5.61 Yield isopleths /Recruit analysis (Knife-edge selection) for L. johnii (all 306 individuals) 2007 5.62 Relative yield-per-recruit and E=1.0 and L0 / biomass-per recruit 306 5.63 Predicted maximum length of L. lutjanus Combined data (2007) based on 306 extreme value theory (Formation et al., 1991). 5.64 Length frequency data fitted Von Bertalanffy growth curve.L. johnii all 307 individuals, (2005-07). 5.65 Estimation of K for A. intermedius by emploing ELEFAN-1 of L. johnii 308 (2005-07). 5.66 Estimation of K by emploing Shepherd’s method for L. johnii 308 (2005-07). 5.67 Powell –Wetherall plot from length frequency data of L. johnii (all 308 individuals) 2005-2007. 5.68 Length converted catch curve for L .johnii for (all individuals) 2005-2007 310 5.69 Jones and Van Zalling plot for estimation of total mortality (Z), (all 310 individuals) of L. johnii whole data three years,2005-2007 5.70 Recruitment pettern of Lutjanus johnii (whole data) for three years 311 5.71 Probability of capture of Lutjanus johnii 2005-2007 by gill net 312 5.72 Virtual population analysis of Lutjanus johnii, 2005-2007 312 5.73 Length based virtual population analysis Lutjanus johnii,2005-2007 312 5.74 Yield isopleths /Recruit analysis (Knife-edge selection) for L johnii 313 (2005-2007) 5.75 Relative yield-per-recruit and biomass-per recruit for L. johnii (2005- 313 2007) 5.76 Predicted maximum length of Lutjanus johnii three years Combined data 313 (2005, 2006 and 2007).
DISTRIBUTION
5.77 Landing of Lutjanus sp at Karachi Fish harbor during the year 1995-2012 318 5.78 Export of Lutjanus species from Pakistan during 2007-2012. 318 5.79 Map for Coastal belt of Sindh 322 5.80 Deposition of fish catch (2003-2012) 322 5.81 (A) Nominal catch of finfish and shell fish (2001-2012) (B) Specieswise 325 Landing at Karachi harbour during 2012,(C) Total export of fish during, 2001-2012. 5.82 (A) Collection by trawl net in Korangi Creak August (2006),(B) Tidal 327 effected area of Korangi Creak Channel, Karachi, near khuddi creek, (C) Ibrahim Haidry, Karachi. 5.83 (A) Main fish market of Ibrahim Haidry (B) L. lutjanus at Karachi Fish 328 Harbor (December 2007) (C) at Ibrahim Hiadery (Fish Market Karachi) November 2007 5.84 A &B L. johnii at Karachi fish Harbor (November 2007). C Mouth of 329 Phitti creek channal
LIST OF TABLE Table Description Page No No
1.1 Landing in m tons at Karachi Fish Harbor during the seven years. 5 3.1 Visual observations of maturity stages of L. lutjanus and L. johnii 93 3.2 Description and classification of the Histological observation of female 94 maturity stages of L. lutjanus and L. johnii. Lutjanus lutjanus (Bloch 1792) 4.1 Values of length weight relationship of L. lutjanus during three years 142 (2005-2007) 4.2 Values of Von Bertalanffy growth curve model plotted for the data of 169 Lutjanus lutjanus (Male) observed during three years (2005-2007) 4.3 Values of Von Bertalanffy growth curve model plotted for the data of L. 170 lutjanus (Female) observed during three years(2005-2007). 4.4 Values of Von Bertalanffy growth curve model plotted for the data of L. 171 lutjanus (Combined)observed during three years (2005-2007) 4.5 Values of Von Bertalanffy growth curve model plotted for three years 172 (Combined) data of L. lutjanus observed during (2005-2007) 4.6 Mean length and observed length values of L. lutjanus (Male) during 178 three years (2005-2007) 4.7 Mean length and observed length values of L. lutjanus (Female) during 179 three years (2005-2007) 4.8 Relative analysis recruitment analysis results of Lutjanus lutjanus 2005 187 4.9 Relative analysis recruitment analysis results 2006 195 4.10 Relative analysis recruitment analysis results 2007 203 4.11 Relative analysis recruitment analysis results (all individuals) 2005-2007 211 4.12 Values of L & K estimated by different routines of FiSAT II for 213 Lutjanus lutjanus (Male) 2005 4.13 Values of L & K estimated by different routines of FiSAT II for 213 Lutjanus lutjanus (Male) 2006 4.14 Values of L & K estimated by different routines of FiSAT II for 213 Lutjanus lutjanus (male) 2007 4.15 Values of L & K estimated by different routines of FiSAT II for 214 Lutjanus lutjanus (female) 2005 4.16 Values of L & K estimated by different routines of FiSAT II for 214 Lutjanus lutjanus (female) 2006 4.17 Values of L & K estimated by different routines of FiSAT II for 214 Lutjanus lutjanus (female) 2007 4.18 Values of L & K estimated by different routines of FiSAT II for 215 Lutjanus lutjanus (all individuals) 2005 4.19 Values of L & K estimated by different routines of FiSAT II for 215 Lutjanus lutjanus (all individuals) 2006 4.20 Values of L & K estimated by different routines of FiSAT II for 215 Lutjanus lutjanus (all individuals) 2007 4.21 Estimations of total mortality (Z) by length converted catch curve routine 216 FiSAT II Lutjanus lutjanus A. Male B. Female and C all individuals of three years (2005-2007)
4.22 Natural mortality (M) of L. lutjanus estimated by FiSAT II during three 217 years 2005-2007 (Male, Female and all individuals) 4.23 Total mortality ( Z) of Lutjanus lutjanus estimated by FiSAT II during 218 three years (2005-2007) 4.24 Estimation of Growth performance indices of Lutjanus lutjanus during 219 three years (2005-2007) 4.25 Estimated values by FiSAT II as prediction of the maximum length 219 from extreme value for L. lutjanus (2005-2007) 4.26 Comparison of present study with previously reported results for 227 L. lutjanus 5 RESULTS Lutjanus johnii (Bloch 1792) 5.1 Values of Length weight relationship pf L. johnii during three years 246 2005-2007. 5.2 Linear regression analysis for TL (cm) and wt (gm) relationship of L. 260 johnii collected from three diffetrent l variable. 5.3 Values of Von Bertalanffy growth curve model plotted for the data of 275 Lutjanus johnii (Male) observed during 2005-2007. 5.4 Values of Von Bertalanffy growth curve model plotted for the data of 276 Lutjanus johnii (Female) observed during 2005-2007. 5.5 Values of Von Bertalanffy growth curve model plotted for the data of 277 Lutjanus johnii (all individuals/Combined) observed yearly 5.6 Values of Von Bertalanffy growth curve model plotted for the combined 278 data of Lutjanus johnii for three years 2005-2007. 5.7 Values of mean length at age for the male of specimens Lutjanus johnii 283 during three years (2005-2007) 5.8 Mean length and observed length at age of L .johnii (Female) during three 284 year 2005-2007. 5.9 Values of L & K estimated by different routines of FiSAT II for L. 314 johnii (all individuals) 2005. 5.10 Values of L & K estimated by different routines of FiSAT II for L. 314 johnii (all individuals) 2006. 5.11 Values of L & K estimated by different routines of FiSAT II for L. 314 johnii (all individuals) 2007. 5.12 Values of L & K estimated by different routines of Fi SAT II for L. 315 johnii (all individuals) 2005-2007. 5.13 Estimations of total mortality (Z) by length converted catch curve routine 315 Fi SAT II L. johnii of three years (2005-2007) 5.14 Total mortality (Z) of L. johnii estimated by FiSAT II for 2005-2007. 315 5.15 Natural mortality (M) of L. johnii estimated by FiSAT II during three 316 years (2005-2007). 5.16 Estimated values of Growth performance indices of L. johnii (all 316 individuals ) 2005-2007 5.17 Lutjanus sp observed in Pakistan along Sindh Coast 319 5.18 Species composition of fishes caught from Khuddi creek (Korangi) 323 Karachi during boat collection. 5.19 Species wise landing of fish species at Karachi Fish Harbour with special 326 reference to Lutjanus species during 2012. 5.20 Comparison of present study with previously reported results for L. 343 johnii
LIST OF GRAPHS Graph Description Page No 1.1 Year wise 1995 to 2012 Landing of Lutjanus sp at Karachi Fish 6 harbor (Marine Fisheries Department, Government of Pakistan) 4. Results Lutjanus lutjanus 4.1-4.12 Size frequency distribution of Lutjanus lutjanus 2005 118 4.13-4.24 Size frequency distribution of Lutjanus lutjanus 2006 119 4.25-4.36 Size frequency distribution of Lutjanus lutjanus 2007 120 4.37 Total No’s of specimens of Lutjanus lutjanus studied during Three 121 years (2005-2007). 4.38 Total No’s of specimens of L. lutjanus studied during 2005 121 4.39 Total No’s of specimens of Lutjanus lutjanus studied during 2006 121 4.40- 4.51 Percentage frequency distribution for gonadal maturity stages of 130 Lutjanus lutjanus observed during the year 2005. 4.52 - 4.63 Percentage frequency distribution for gonadal maturity stages of 131 Lutjanus lutjanus observed during the year 2006. 4.64 -4.75 Percentage frequency distribution for gonadal maturity stages of 132 Lutjanus lutjanus observed during the year 2007. 4.76 Monthly changes in gonad somatic index (GSI+) and oocyte 133 composition of Lutjanus lutjanus. 4.77 Size at 50 % maturity of male specimens of Lutjanus lutjanus. 134 4.78 Size at 50 % maturity of female specimens of Lutjanus lutjanus 134 4.79–4.84 Oocytes size frequency distribution of L. lutjanus (stage-V) ripe 137 females 18.5 cm to 27.5 cm, during the three year (2005-2007) 4.85-4.87 Relationship between annually potential fecundity with length (TL 139 cm) of L.lutjanus during 2005-2007. 4.88-4.90 Relationship between annually potential fecundity with somatic wt 141 gm of .L lutjanus during 2005-2007 4.91 Percentage frequency distribution of Lutjanus lutjanus during the 141 year 2005-2007. 4.92-4.94 Length weight relationship of L lutjanus during three years (2005- 143 2007). 4.95-4.106 Regression analysis between Fish wt (gm) VS Fish length (TL) of 145 Lutjanus lutjanus during 2005. 4.107-4.118 Regression analysis fish length (TL) Vs Scale size (mm) of 146 L. lutjanus from January 2005 to December 2005. 4.119-4.130 Regression analysis between Fish length (cm) VS Otolith size 147 (mm) of L. lutjanus during January to December 2005. 4.131-4.142 Regression analysis between Fish wt (gm) VS Otolith wt (OT) of 148 L. lutjanus from January 2005 to December 2005. 4.143-4.154. Regression analysis between Fish wt (gm) VS Fish length (TL) of 149 Lutjanus lutjanus during January to December 2006 4.155-4.166 Regression analysis fish length (TL) VS Scale size of L. lutjanus 150 from January to December 2006. 4.167-4.178 Regression analysis between Fish length (cm) VS Otolith size 151 (mm) of Lutjanus lutjanus from January to December 2006.
4.179-4.190 Regression analysis between Fish wt (gm) VS Otolith wt (OT) of 152 Lutjanus lutjanus from January to December 2006. 4.191-4.202 Regression analysis between Fish Length (cm) VS Fish wt (gm) of 153 Lutjanus lutjanus January to December 2007. 4.203- 4.214 Regression analysis between Fish Length (cm) VS Fish wt (gm) of 154 Lutjanus lutjanus January to December 2007. 4.215-4.226 Regression analysis fish length (TL cm) VS Scale size (mm) of 155 L. lutjanus January to December 2007. 4.227-4.238 Regression analysis between Fish length (TL cm) VS Otolith size 156 (mm) of L. lutjanus January to December 2007. 4.239-4.250 Regression analysis between Fish wt (gm) Vs Otolith wt (OT) of 157 L. lutjanus January to December 2007. 4.251-4.253 Von Bartalanffy growth function (VBGF) fitted to length age data 165 of L.lutjanus (male) during three years (2005-2007) 4.254-4.256 Von Bertalanffy growth function (VBGF) fitted to length age data 166 of Lutjanus lutjanus (Female) during three years (2005-2007). 4.257-4.259 Von Bartalanffy growth function (VBGF) fitted length age data of 167 L. lutjanus (Combined) during three years (2005-2007) 4.260-4.262 Von Bertalanffy growth function (VBGF) fitted to length whole 168 data L.lutjanus during three years (2005-2007) 4.263-4.265 Von Bertalanffy growth curves fitted to length age data by “R” 173 statistical software of L. lutjanus (Male) 4.266-4.268 Von Bertalanffy growth curves by “R” software fitted to length age 174 data of L. lutjanus (Female) for three years (2005-2007). 4.269-4.271 The Von Bertalanffy growth curve by “R” software fitted to length 175 age data of L. lutjanus, all individuals (2005-2007) 4.272-4.274 The mean length and observed length of L. lutjanus (male) during 176 three years (2005-2007). 4.275 -4.277 The mean length and observed length of L. lutjanus Female during 177 three years (2005-2007). Results Lutjanus johnii 5.1- 5.12 Size frequency distribution of Lutjanus johnii 2005 223 5.13-5.24 Size frequency distribution of Lutjanus johnii 2006 224 5.25 -5.36 Size frequency distribution of Lutjanus johnii2007 225 5.37 Total No’s of specimens of L. johnii studied all individuals (2005- 226 2007) 5.38 Total No’s of specimens of L. johnii studied all individuals 2005 226 5.39 Total No’s of specimens of L. johnii studied all individuals 2006 227 5.40 Total No’s of specimens of L. johnii studied all individuals 2007 227 5.41-5.52 Percentage frequency distribution for maturity stages 2005 235 5.53-5.64 Percentage frequency distribution for maturity stages 2006 236 5.65-5.76 Percentage frequency distribution for maturity stages 2007. 237 5.77 Marginal increment analysis of Lutjanus johnii (2005-2007) 238 5.78 Size at 50 % maturity of L. johnii (Male) during three years 239 5.79 Size at 50 % maturity of Lutjanus johnii of (Female) specimens. 239 5.80-5.584 Oocytes diameter frequency distribution of stages of L. johnii 242 (stage-V) ripe ovary of females during the three year (2005-2007). 5.85 Relationship between annually potential fecundity with somatic 243 weight gm of Lutjanus johnii during 2005-2007. 5.86 Fecundity of Lutjanus johnii during three years (2005-2007) 244 5.87 Percentage frequency distribution of gonadal stages of L. johnii 245 during the year 2005-2007. 5.88 Linear regression analysis for length weight Relationship 2005 246 5.89 Linear regression analysis for length weight Relationship 2007 247 5.90 Linear regression analysis for length weight Relationship 2007 247 5.91-5.102 Regression analysis between fish length (TL cm) and fish weight 249 (gm) relationship of L. johnii ,2005 5.103-5.114 Regression analysis between Length (TL cm) and weight (gm) 250 relationship of L. johnii 2006. 5.115-5.126 Regression analysis between Length (TL cm) and weight (gm) 251 relationship 2007. 5.127-5.138 Regression analysis between Fish weight (gm) - Otolith (mg) 252 weight relationship 2005. 5.139-5.150 Regression analysis between Fish weight (gm) - Otolith weight 253 (mg) relationship 2006 5.151 -5.162 Regression analysis between Fish weight (gm) - Otolith weight 254 (mg) 2007. 5.163-5.176 Regression analysis between Fish length cm (TL) and Otolith size 255 (mm) 2005. 5.177-5.188 Regression analysis between Fish Length cm (TL), Otolith size 256 (mm) 2006. 5.189-5.200 Regression analysis between Fish length cm (TL),scale size(cm) 257 2005. 5.201-5.211 Regression analysis between Total Length cm (TL) scale size mm 258 2006. 5.212-5.223 Regression analysis between Fish Length cm (TL) scale size (mm) 259 2007. 5.224-5.226 Von Bertalanffy growth function (VBGF) fitted to length age data 271 of Lutjanus johnii (Male) 2005-2007. 5.227-5.229 Von Bertalanffy growth function (VBGF) fitted to length age data 272 of Lutjanus johnii (Female) of three years 2005-2007. 5.230-5.232 Von Bertalanffy growth function (VBGF) fitted to length age data 273 of Lutjanus johnii (all individuals)data of three years (2005-2007). 5.233-5.235 Von Bertalanffy growth function (VBGF) fitted to length age 274 combined data L. johnii during three years (2005-2007). 5.236-5.239 The Von Bertalanffy growth curves by “R” software A fitted to 279 length age data of Lutjanus johnii (Male) 2005-2007. 5.240-5.242 The Von Bertalanffy growth curves by “R” software fitted to length age 280 data of Lutjanus johnii (female) for three years(2005-2007). 5.243-5.245 The mean length and observed length of L. johnii (Male) 2005 - 281 2007 5.246-5.248 The mean length and observed length of L. johnii (Female) 282 2005-2007 5.249 (A) Specimens observed during the Boat collection from Gangyaro 324 creek (B) Specimens observed during the Boat collection from Khuddi creek (Korangi) Karachi
ABSTRACT
The coastal belt of Pakistan is about 1,050 km long, divided in to two regions Northwestern region (Balochistan and Makran coast, have 800 km long coastline which extending from Hub River to north west of Karachi with a narrow continental shelf), Southern region (Sindh coast having 250 km long).
In the present study two members of family Lutjanidae .i.e. Lutjanus lutjanus and Lutjnaus johnii were collected on monthly basis in respect of their biology, age and growth, population dynamics parameters and distribution along Sindh coast during three years (2005-2007) from main fish markets and boat collections by trawl and gill net from creek system.
Collections brought to laboratory at University of Karachi on monthly basis, samples were identified, length (TL in cm), weight (in gm), scales, otolith and gonads of each specimen were examined and data was recorded. About 30 samples of gonads were selected after visual observation, maturity of gonads and values of Gonad somatic index (GSI) were studied which shows spawning season of both species, the relationship between fecundity and somatic weight (gm) and length (TL cm) were studied that’s seems to be the large fish produced maximum eggs in compression of small one.
Length –weight relationship of both species shows strong correlations, for the determination of age the growth ring were observed from otolith section which is more reliable in compression to whole otolith and fish scale. The opaque zones from sectioned were studied through marginal increment analysis, shows on opaque zone delineated per year in both species and the rings found on scales were also studied, the results shows the maximum age 11 years of Lutjanus lutjanus at 27.5 cm (TL) and Lutjanus johnii 22 years with 75.5 cm (TL).
Length at age data best fitted to Von Bertallanfy Growth Function (VBGF) to obtained the curve, shows the both species are slow growing in large size. Relationship between fish length (TL in cm), fish weight (in gm), fish length (TL in cm) vs otolith radius (mm), fish length (cm) vs otolith weigh (mg) were determined through regression analysis.
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The length frequency data was used as put in FiSAT II (version 1.2.2), FAO stock assessment tool software for determination of population dynamics parameters .i.e. Asymptotic length (L∞), growth constant (K), mortality (total mortality, fishing mortality and natural mortality), recruitment pattern, virtual population analysis (VPA), probabilities of capture, yield per recruit Y/R and B/R and growth performance indices. The results showed that the exploitation rate of small size fishes were fished by gill net fishing and mortality estimation showed that the both species have not been over harvested in coastal area of Pakistan, high recruitment pattern found in primary growth season, both species are not exploited above the maximum sustainable yield.
The results shows that both species are lived in similar habitat and widely distributed along the coastal belt of Sindh, Lutjanus lutjanus are offshore coral reefs and trawling grounds frequently encountered in large schools with other Lutjanus species and trawled to depth of almost 100 m, feed on fishes and crustaceans Lutjanus johnii are frequently found in coral reef while adult and juveniles found in mangrove estuaries, feed upon fishes and benthic invertebrates including shrimps, crabs and cephalopod.
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INTRODUCTION
Pakistan is situated between 20º and 25º North 59º and 70º East at Northern side of Arabian Sea, in relation to fishing area, Pakistan has 1100 km coastline mainly considered in two areas:
a- North western region i.e. Balochistan. b- Southeastern region in Sindh Coast.
At border of Iran 5 bays are present including Sonmiani Bay and Gawater Bay and the Sindh coast stretches about 270 km from Karachi to Sir Creek up to Indian border. Arabian Sea where Pakistan is situated contains one of the largest potential of marine fauna (90 % shrimp and 52% fishes) Majid and Arshad 1985 and FAO, 2000 reported about 400 fish species belonging to 21 Orders, 9 Sub Orders. Indus deltaic region is part of mangroves and Creeks beyond continental shelf is km2 43.70 % (Earth trends 2003). Sindh Province almost commands 350 sq km of marine waters with tremendous resources which are being exploited unabatedly which is likely to cause depletion of stocks. Mangroves are having great importance in marine habitat and grow in 240 km2 area at southern coast line of Pakistan where they are not subjected to strong wave and tidal action. This area is nutritionally rich, providing ideal habitat, nursery ground and reservoir for larval and juvenile stages of fishes, which drift toward the coast to complete their life cycle and go back towards open sea for serving as secondary trophic level in food web.
About 14,450 fish species are distributed in oceanic waters in which 79% are living near shore line in shallow waters at about 200m depth, about 28000 (9,968 fresh water and 1,8032 are marine and diadromous) Members of Family Lutjanidae are widely distributed throughout the world especially in warm waters, adult mostly bottom associated (Murphy and Collier 1996), usually found in coastal waters, but some are restricted to fresh water (Nelson, 1994).
Majority of Lutjanids are found in shallow waters reef area and some range in to deeper waters (550 m), These perch like fishes are very common in Indo Pacific region waters living in off shore near continental shelf, (Roberts et al., 2001) mostly spawn from June to October, these are most important and very popular fishes of the
3 world having great export value. Snappers are of warm temperate and tropical region fisheries appear to be particularly at risk (Vaughan et al.,1993 ; Zhao; McGoven, and Harris, 1997; Zhao and McGovern 1977; Kyushin et al., 1982 ; Dor, III.1991 ; Allen and Talbot,1985 ; Allen and Swainston,1988 ; Krishna and Misrah,1993 and (Sadovy, 2000) have been reported that the fishes of family Lutjanidae such as Lutjanus malbaricus, Lutjanus johnii, Lutjanus lutjanus are very common in Indian ocean, Gulf of Mexico is the main center of red snappers. Larvae of Lutjanids are mostly found at east coast of USA, Houde et al., 1989, similarly present all around the year, Powell, 1979 and 79% are found abundantly in summer season at Gulf of Mexico, Houde and Taniguchi (1979), described 8 species from India. Huda and Khan, 1996 recorded only four species from Pakistani waters. Quality of flesh of Lutjanids is very good containing 45.6 % to 50.3 % meat and 21.0 % of protein, Alverson and Carnacy (1975).The Lutjanids have slow growth and late maturity rate, Musick (1999).They have seasonal and spawning migration, complex social structure and sex reversal as reported by Coleman et al., 2011. Lutjanids are long living, life span ranges from 25- 50 years to as high as 53 in Red snappers with 60 to 100 cm in length. Goodyear 1995 found at 75-100 m depth and at 20 to 26 ºC, feed on invertebrates such as crustacean, cuttlefish and worms and small fishes. Allister and Collin 1992 ; Mees, 1993 and Allen, 1985 reported that Lutjanus vivanus and Lutjanus buccanella found at 90 m to 140 m depth. Previous studies on the biology, ecology, age & growth and stock assessment of Lutjanids have been reported by Thompson and Munro, (1983) ; Leis, (1987) ; Nelson and Manooch, (1982) ; Johnson, (1980) and Jearld, (1983). In South Asia, Southern China and Middle East, Leung 1994 and Emata 2003 reported the Lutjanids have great potential in Aquaculture in Marine Habitat. In the Gulf of Mexico Lutjanus campechanus (Red snapper) and Rhomboplites aurorubens (vermilion snapper) are over fished as reported by Coleman et al., 2011.
Along the coast of Pakistan, about 20 species of family Lutjanidae are reported by Bianchi, 1985. Work on the ecology and stock assessment of Lutjanids have been undertaken such as Mathews and Samuel, (1990) discussed the maximum length and asymptotic length in fishes. Bullock and Murphy (1992) studied their age and growth and reproduction. Haight et al., (1993) reported feeding ecology of from Hawaiin snapper another study. Mees, (1993); Acosta and Appeldoorn, (1992) estimated growth, mortality and yield per recruit for Lutjanus syngris in Puerta Rico. Tabash
4 and Sierra, (1996) assessed Lutjanus vivarus (Slik snapper) and Lutjanus graccanella (Black fin snapper) stocks in Costa Rica. Allen 1985 has given annotated and illustrated catalogue of Lutjanids of the world. Snapper can reach large size > 100 cm total length at 40 kg. Worldwide landing of Lutjanids are estimated by FAO, as about 60,000 metric tons. The year wise landing of snappers from Pakistani waters and EEZ (Economic exclusive zone) at Karachi recorded by Marine Fisheries Department, Government of Pakistan. Table 1.1 & Graph.1.1.
Year Sindh EEZ Total
1995 3123 18 3123
1996 1989 71 1989
1997 2342 22 2342
1998 3176 13 3176
1999 3,112 83 3,195
2000 2,976 16 2,976
2001 2,709 83 2,709
2002 2,670 13 2,670
2003 2,190 8 2,190
2004 2, 256 4 2260
2005 2, 168 1 2169
2006 2,009 2 2,009
2007 1, 890 4 1, 890
2008 2, 111 6 2, 111
2009 1,998 2 1,898
2010 1,765 1 1,765
2011 1,432 4 1,432
2012 1,532 5 1,432
Table 1.1 Landing in m /tons at Karachi Fish Harbor during the seven years.
5
M/tons
Year wise landing of Lutjanus sp during 1999 -2012 Graph. 1.1 Year wise 1995 to 2012 Landing of Lutjanus sp at Karachi Fish harbor (Marine Fisheries Department, Government of Pakistan).
1.1 Classification
Family Lutjanidae comprises of four sub Families (FAO, 2002)
1. Sub Family Etinae Genus Rtelies Cuvier, 1828 Randallichthys Anderson, Kami and Johnson, 1977 Aphareus Cuvier, 1830 Pristipomides Bleeker, 1852 Aprion Valenciennes, 1830 2. Sub Family Apsilnae Genus Parapristipomides Kami, 1973 Paracaesio Bleeker, 1875 Lipocheilus Anderson, Talwar & Johnson, 1977 Apsilus Valenciennes, 1830 3. Sub Family Paradichthyinae Genus Sympohorichthys Munro .S.R. 1967 Symphorus Gunter, 1872 4. Sub Family Lutjaninae
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Figure. 1.1. Lutjanus johnii from Karachi Fish Harbor (7750 gm, TL 75 cm)
1.2. Descriptive Characters of Family Lutjanidae
Sub family Lutjaninae contains 2/3 of the species of Lutjanidae; species of this sub family build a major and important component of reef fisheries throughout the geographical range (Anderson, et al., 1967; Nelson, 1994; FAO, 2002). Mouth terminal, moderate to large extending when opened (Protrusible), jaws bear large conical and sharp canine teeth in few rows (except in Apherius), molri form teeth present only in genus Hyplopagris. Teeth present at roof of the mouth; preopercle usually serrate; often finely. Dorsal fin continuous or slightly notched with 10-12 spines and 10-17 soft rays; anal fin with 3 spines and 7-11 soft rays; pelvic fins originating just behind pectoral base. Pelvic fins with 1 spine and 5 soft rays. Lateral line complete, straight or curved gently. Body covered with moderate to small ctenoid scales. Anterior part of head (Snout and Preopercle area) without scales; some rows of scales are found on cheek, preopercle and gill cover, (Munro, 1967; Qureshi, 1960; Allen and Talbot, 1985 and Nelson, 1994) Figure.1.1.
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1.3. Lutjanus lutjanus (Bloch 1790)
Figure.1.2. Lutjanus lutjanus (Bloch 1790), Bigeye Snapper, Hira, Kunla, Kunalcha, Rosy Snapper 27 cm TL (collected from Karachi Harbor, 2007).
Synonyms of Lutjanus lutjanus (Bloch 1790)
Diacope lieolata Rüppell 1829
Lutjanus lineolatus Rüppell, 1829
Lutjanus lutjanus Bloch, 1790
Lutjanus blochii Lacep, 1802
Mesoprion caroui Cuvier, 1828
Mesoprion erythrognathus Valenciennes, 1831
Mesoprion xanthopterygius Bleeker, 1849
Rhomboplitoides megalops Fowler, 1918
Serranus nouleny Valenciennes, 1828
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1.4. Lutjanus johnii (Bloch 1792)
Figure. 1.3. Lutjanus johnii (Bloch 1792) John’s Snapper, Mosses Perch, Hira, Kunla, Kanalcha, 35 cm TL (caught during boat collection 2007).
Synonyms of Lutjanus johnii (Bloch 1792)
Anthias johnii (Bloch 1792)
Coius catus (Buchanan 1822)
Diacope xanthozona (Bleaker 1845)
Lutjanus johnii (Bloch 1792)
Mesoprion yapilli (Cuvier 1828)
Serranus pavoninus (Valenciennes 1831)
Sparus tranquebaricus (Shaw1803)
Lutjanus johni (Bloch 1792)
Pinjalo pinjalo (Bleeker)
1.5. Distinguishing Characters
Lutjanus lutjanus is commonly known as Big eye snapper have Generally silvery white, with a broad yellow stripe running along the side from the eye to the caudal fin
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base. A series of faint narrow yellow horizontal lines is on the lower half of the body. The fins are pale yellow to whitish, Figure.1.2.
Lutjanus johnii is commonly known as finger mark john’s snapper or spotted scale sea perch called ‘Goldy’ because its golden and silvery coloration, a dark large blotch located approximately two third above lateral line at mid body.Figure.1.3.
1.6. Key to species of family Lutjanidae (Figure.1.4 A and B)
1a. Pre orbital (“suborbital”) space (distance between upper jaw and eye) very narrow, 9.2 to 16.3 times in head length body slender, usually 3 (sometimes2.9) or more times in standard length; (Fig.1-a) dorsal-fin spines usually XI (occasionally X or rarely XI); soft dorsal-fin rays 12. …………………………………………….. 2
1b. Pre orbital (“suborbital”) space wider, 3.3 to 8.9 times in head length (Fig. 1b); body deeper, 2.1 to 3.1 times, but usually less than3 times, in standard length; dorsal- fin spines variable, X to XII; soft dorsal-fin rays occasionally12 (usually 13 or more) ...... 3
2a. Body depth 3.5 to 3.8 times in standard length; a dark band from snout to caudal- fin base and 2 pearly spots above lateral line, 1 below spinous portion and the other below soft portion of dorsal fin …………………….….. Lutjanus biguttatus (Distributed at central Indian Ocean to Melanesia)
2b. Body depth 2.9 to 3.3 times in standard length; tongue with a patch of fine granular teeth; color generally silvery white with a broad yellow stripe along middle of side to caudal-fin base, and narrow yellowish lines, corresponding with longitudinal scale ro……………………………………………….. *Lutjanus lutjanus (Distributed at Eastern Africa to western Pacific)
3a. Ground color pale (mainly yellow in life) with a series of 4 or 5 longitudinal stripes (blue in life, often brownish in preservative) on side ….………………... 4
3b. Color not as above …………………………………..……..….………………… 6
4a. Dorsal-fin spines XI or XII ………………………….…….. Lutjanus bengalensis
4b. Dorsal-fin spines X ………………………………….……………………………5
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5a. Four stripes on side, belly more or less abruptly whitish, frequently with thin grey lines; scale rows on cheek 5 or 6; upper pectoral-fin rays darkis ...... Lutjanus kasmira (Distributed at Eastern Africa to central Pacific)
5b. Five stripes on side, belly not abruptly whitish and without thin lines; scale rows on cheek 10 or 11; upper pectoral-fin rays pale …… . Lutjanus quinquelineatus (Distributed at Central Indian Ocean to western Pacific)
6a. Longitudinal scale rows above lateral line obliquely positioned Fig. 2a …………7
6b. Longitudinal scale rows above lateral line entirely horizontal (Fig. 2b) or some rows rising obliquely from below middle part of dorsal fin Fig. 2…………….… 31
7a. Vomarine tooth patch triangular or diamond- shaped with a medial posterior extension (Fig. 3c) …………………………………………………………….…..……. 8
7b. Vomarine tooth patch crescent to triangular without a posterior extension …. . 13
8a. Axil of pectoral fins with distinct black spot on upper portion; a series of 8 or 9 relatively broad orange or yellow stripes on side; soft dorsal-fin rays usually 15 (occasionally 14, rarely 16); soft anal-fin rays 9 ………… Lutjanus carponotatus (Distributed at India to Melanesia and Australia)
8b. Axil of pectoral fins without black spot; color not as above; soft dorsal-fin rays usually 13 or 14 (rarely 12); soft anal-fin rays usually 8 (rarely 9) ……...….……. 9
9a. A large black spot usually present on upper side, juveniles sometimes with an oscillated spot or a series of 4 to 7 broad dark stripes on side (adults of Lutjanus fulviflamma with yellow stripes) ……………………………………...……….. 10
9b. Black spot absent; a series of narrow, yellowish longitudinal lines on side, those on upper back slanting upward toward dorsal-fin base, sometimes an enlarged darker stripe from eye to middle of caudal-fin base ……………………….……… 11
10a. Soft dorsal-fin rays usually 14; a relatively wide gap between temporal scale bands of each side (Fig. 3a); spot on upper side situated mainly above lateral line; young specimens with series of 4 to 7 broad stripes (blackish to orange or yellow- brown in life) on side, these persisting as thin stripes in adults from the western Indian Ocean …………………….…………...…………………. Lutjanus russelli (Distributed at Eastern Africa to Western Pacific)
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10b. Soft dorsal-fin rays usually 13; little or no gap between temporal scale bands of each side (Fig. 3b) spot on upper side situated mostly below lateral line or bisected by it, spot sometimes very elongated; young specimens without series of 4 to 7 broad dark stripes on side …………………………. Lutjanus fulviflamma (Distributed at Eastern Africa to Central South Pacific)
11a. Midlateral stripe usually broader and darker than other stripes on side; transverse scale rows on cheek 7 to 10 …………………………………….… Lutjanus vita (Distributed at Western Indian Ocean to Western Pacific)
11b. Mid lateral stripe not broader or darker than other stripes on side, yellow in life and faint or absent in preserved specimens; transverse scale rows on cheek usually 6 /7 (occasionally 8) …….………………………...…………………………… 12
12a. Pre dorsal scales extending to mid-inter orbital level; a blunt, flattened spine on upper margin of opercula, above the main centrally located spine (Fig. 4a); inter orbital width 4.4 to 6.5 in head length; total gill rackers on first gill arch (including rudiments) 18 to 21 ……………..………………… Lutjanus madras (Distributed at Eastern Africa to Indonesia and the Philippines)
12b. Pre dorsal scales extending to level of rear part of orbit; blunt spine above central opercula spine absent (Fig. 4b); inter orbital width 6.5 to 6.9 in head length; total gill rackers on first gill arch (including rudiments) 15 or 16 … Lutjanus mizenkoi (Distribution at Indonesia to Samoa)
13a. Total gill rackers (including rudiments) on first gill arch (including rudiments) 25 to 30 14 13.b Total gill rackers (including rudiments) on first gill arch (including rudiments) 14 to 23 ……………………………………………………..……………. . 15
14a. Dorsal fin with X spines and 14 soft rays; longitudinal scale rows below lateral line parallel to axis of body (Fig. 5a); caudal fin emarginated; color generally pale with a golden-brown mid lateral stripe, slightly narrower than eye, and a series of oblique golden-brown lines ascending from lateral line to base of dorsal fin ………………………………………….…………………...…….. Lutjanus adetii (Distributed at Eastern Australia and New Caledonia)
14b. Dorsal fin with X spines and 13 or 14 soft rays; scale rows below lateral line ascending obliquely (Fig. 5b); caudal fin distinctly forked with rounded lobes;
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color deep red to grey, fins red or dark brown to blackish ……. Lutjanus gibbus (Distributed Eastern Africa to Central West Pacific)
15a. Soft anal-fin rays 10; dorsal fin with XI spines and 16 rays (rarely 15); color pattern consisting of 3 dark brown to red transverse bars (may be indistinct in large adults) …………………………………………………….. Lutjanus sebae (Distributed at Eastern Africa to Western Pacific)
15b. Soft anal-fin rays 8 or 9; dorsal-fin elements variable, the fin with X or XI spines and 12 to 16 soft rays; color not as above ……………………….…………….. 16
16a. Pre opercula notch distinctive (moderately to well developed,(Fig. 6a) …...…. 17
16b. Pre opercula notch indistinct (shallow or absent, (Fig. 6b) …………………… 21
17a. Soft dorsal-fin rays 15 or 16; body relatively deep, 2.1 to 2.4 times in standard length; head usually with numerous wavy lines (bluish in life); a chalky spot often present below junction of spinous and soft parts of dorsal fin, bordered with black in juveniles, but lost with age; lips thick in large adults …….. Lutjanus rivulatus (Distributed at Eastern Africa to Central South Pacific)
17b. Soft dorsal-fin rays 13 or 14; body usually more slender, 2.3 to 2.8 times in standard length; color not as above; lips not thick in adults …………….…….. 18
18a. Caudal fin and distal third of dorsal fin blackish or dusky brown with a narrow white border ……………………………………………………… Lutjanus fulvus (Distributed Eastern Africa to Central West Pacific)
18b. Caudal fin yellow or grey basally and yellow distally (tan to medium brown in preservative) without narrow white border; distal third of dorsal fin not noticeably darker than remainder of fin ………………………………………..…………. 19
19a. A small chalk-white spot on back just above lateral line at level of anterior part of soft dorsal fin; body depth 2.4 to 2.5 times in standard length; total gill rakers on first gill arch 16 to 19; dorsal-fin spines X ………..………...... Lutjanus stellatus
19b. A large brownish spot in this position, but usually faint or absent in fresh dead or preserved specimens; color generally pink, sometimes with faint yellow stripes (absent in preservative) on side, margin of dorsal fin sometimes blackish; snout 2.8 to 3.2, pre orbital 5.3 to 6.6 times, both in head length; total gill rackers on first gill arch 20 to 23; dorsal-fin spines X or XI ……………………………..... 20
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20a. Dorsal-fin spines X; no yellow stripes on side of body ………. Lutjanus boutton (Distributed at Indo-Malayan Archipelago to New Guinea)
20b. Dorsal-fin spines XI; 10 to 12 faint yellow stripes on side of body ………………………………………...…………………. Lutjanus rufolineatus (Distributed West Pacific to Samoa and Tonga)
21a. Eight broad transverse bands or saddles on upper half of body and a large black blotch in centre of caudal peduncle ……………………… Lutjanus semicinctus (Distributed Indonesia to Central South Pacific)
21b. Color pattern not as above ………………………………………….………………… 22
22a. Color pattern consisting of a series of 5 dark stripes on whitish ground color; 2 or 3 uppermost stripes crossed by dark vertical bars forming a network of light and dark squares; a large dark spot at base of caudal fin ……….. Lutjanus decussates (Distributed Central Indian Ocean to Western Pacific)
22b. Color pattern not as above …………….………………….………………….… 23
23a. Nostrils set in a prominent groove running forward from eye in specimens exceeding about 20 cm standard length (Fig. 7); specimens under this size frequently with 2 whitish spots on upper back, anterior spot below last 4 dorsal-fin spines and color generally dark brown on upper back grading to tan or light brownish (white or pink in life) ventrally; dorsal and caudal fins dusky; outer portion of anal and pelvic fins distinctly blackish; upper third of pectoral fins dusky brown …………….……………………………….……….. Lutjanus bohar (Distributed Eastern Africa to Central Pacific)
23b. Nostrils not set in a groove at all sizes; color pattern not as above; tongue smooth or with a patch of granular teeth ……………………………………………… 24
24a. Caudal fin with a distinctive crescentic black marking, remainder of body and fins uniformly yellowish tan (yellow in life) with a silvery sheen on lower sides …………………………………………………………………….…. Lutjanus lunulatus. (Distributed Central Indian Ocean to Melanesia)
24b. Caudal fin without a distinctive black marking (although a dark smudge or blotch present on middle caudal-fin rays of L. bitaeniatus under about 20 cm standard length); color of body and fins variable …………………………………………….. 25
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25a. A black spot on upper side at level of lateral line below soft dorsal fin (faint or occasionally absent in large adults); remainder of body and fins mainly pale (fins yellow, body pink or yellow in life); tongue with a patch of find granular teeth, although sometimes absent in juveniles …………………. Lutjanus monostigma (Distributed Eastern Africa to Central Pacific)
25b. Black spot on upper side of body absent, although a saddle or spot sometimes present on upper portion of caudal peduncle; tongue smooth …..... Lutjanus bohar
26a. Dorsal-fin spines XII; a series of 5 or 6 dusky stripes (yellow in life, may be faint in preservative); longitudinal rows of scales below lateral line rising obliquely …………………………………………………………….. Lutjanus dodecacanthoides (Distributed Indonesia and Philippines)
26b. Dorsal-fin spines X or XI; color not as above; longitudinal rows of scales below lateral line parallel to axis of body or rising obliquely …………………...... 27
27a. Axils of pectoral fins black (Fig. 8); color overall deep red in life; posterior dorsal- and anal-fin rays elongated to form pointed fins; soft anal-fin rays 8 Lutjanus timorensis (Distribution Eastern Indian Ocean to Western Pacific)
27b. Axils of pectoral fins without black marking; color variable, although often red in life; posterior dorsal- and anal-fin rays low and rounded or tall and pointed, but specimens having latter condition usually with 9 soft anal-fin rays ………………28
28a. Dorsal-fin spines X; soft anal-fin rays usually 8 (rarely 9); tongue with a patch of fine, granular teeth; color variable, pink to grey-brown (tan to brown in preservative);Juveniles without black saddle on upper caudal peduncle ……… ..29
28b. Dorsal-fin spines usually XI (rarely X); soft anal-fin rays usually 9 (occasionally 8);tongue smooth; color largely reddish (brown in preservative); juveniles usually with a black saddle on upper caudal peduncle ……………………………………….30
29a. Inter orbital width 4.9 to 5.2 times in head length; body relatively deep, its depth 2.3 to 2.5 times in standard length; snout-forehead profile straight or convex; color generally red or pink (brown to yellowish in preservative), fins pale except in juveniles which may have a crescent blotch in middle of caudal fin …………………………………………………………..… Lutjanus bitaeniatus (Distributed Eastern Indian Ocean and Indonesia)
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29b. Body generally more slender, its depth 2.5 to 2.8 times in standard length; snout- forehead profile concave in specimens over about 15 to 20 cm standard length; color generally grey-brown, reddish or pink ventrally, dorsal and caudal fins dusky brown or black; juveniles with a broad, black ……… Lutjanus lemniscatus (Distributed Eastern Africa to Western Pacific)
30a. Mouth relatively small, maxilla length much less than distance between bases of last dorsal- and anal-fin rays (Fig. 9a);(specimens in excess of 15 cm standard length); some longitudinal scale rows below lateral line slanting obliquely in posterior direction toward dorsal profile; head profile convex (in specimens over about 15 cm standard length …………..………………..…Lutjanus erythropterus (Distributed at Northwestern Indian Ocean to Western Pacific)
30b. Mouth larger, maxilla length about equal to distance between bases of last dorsal- and anal-fin rays (Fig. 9b); inter orbital width 5.1 to 6.6 times in head length (specimens in excess of 12 cm standard length); longitudinal scale rows below lateral line horizontal, although some rows may slant obliquely in juveniles under about 10 cm standard length; head profile straight or slightly concave ……………………………………………………………...……. Lutjanus malabaricus (Distributed Eastern Africa to Western Pacific)
31a. Color pattern consisting of 4, relatively wide dusky brown or blackish stripes on pale ground; only juveniles to 15 cm standard length known ………………………………………………………………………. Lutjanus maxweberi (Distributed Philippines, Indonesia, and New Guinea)
31b. Color pattern not as above …………………………………..…………………. 32
32a. Vomerine tooth patch triangular with medial posterior extension; pre orbital space narrow, 8.6 to 10.3 times in head length; a prominent black spot, larger than eye, bisected by the lateral line below posterior part of spinous dorsal fin ……………………………………………………………………… Lutjanus ehrenbergii (Distributed Eastern Africa to Western Pacific)
32b. Vomerine tooth patch crescent to triangular without a medial posterior extension; pre orbital space wider, 4.7 to 4.9 times in head length; black spot on back present or absent …………………………………………………...……………………33
33a. A large black spot on upper back usually present, if absent ground color pale… 34 16
33b. Black spot on upper back absent, ground color dark ………………………..… 35
34a. Ground color pale, each scale on side often with a brownish spot forming longitudinal rows on side; large spot on back, if present, situated mainly above lateral line; inter orbital width 5.6 to 7.3 times in head length; pre orbital space 4.9 to 6 times in head length; tongue with a patch of fine granular teeth ……………………………………………………………….... *Lutjanus johnii (Distributed Indo West Pacific and Eastern Africa to Central South Pacific)
34b. Ground color dusky brown; large spot on back bisected equally by the lateral line; Inter orbital width 5 to 5.6 times in head length; pre orbital space about 6.8 times in head length; tongue smooth …………………………………. Lutjanus fuscescens (Distributed Fresh waters of China, Philippines, Indonesia, and New Guinea)
35a. Body depth 2.5 to 2.9 (average about 2.7) times in standard length; least depth of caudal peduncle 3 to 3.5 times in head length; longitudinal scale rows on upper back parallel to lateral line interiorly and some rows usually ascend obliquely below posterior dorsal-fin spin …………..……..……… Lutjanus argentimaculatus (Distributed brackish estuaries and lower reaches of fresh-water streams; eastern Africa to Central Pacific)
35b. Body depth 2.2 to 2.6 times in standard length; least depth of caudal peduncle 2.5 to 3 times in head length; longitudinal scale rows on upper back entirely parallel to lateral line (Fig. 2c) …………………………………………. Lutjanus goldiei
Allen, G.R., 1985. (FAO Species Catalogue. Vol. 6. Snappers of the world. An annotated and illustrated catalogue of lutjanid species)
17
A
18
B
Figure 1.4. A & B. Different shapes of Lutjanus sp
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1.7. Determination of age and growth
The population health of fish is needs a reliable and accurate technique and for aging the fish is required, for the determination of age fisheries biologist used different methods and hard parts of the body are very important for this purpose like vertebrae, spines, Scale, Otolith, used commonly (Campana and Neilson, 1985; Francis, et al., 2010 ; Davis, 1992 and Campana, 2001). Earlier the fish scale was used to determine age of fish but data yield was not reliable because fish scale showed irregularities in case of slow growing and long aged fish species (Beamish and Mc Farlane, 1983). Otolith is a mostly reliable therefore this hard part of fish showed clear summer and winter growth zones and used for determination of age (Francis et al., 1992). During the last some years a technique for annual growth zones for tropical and sub tropical species is validate (Samuel et al., 1987; Campana, 1992 and James, 1996).
Basically the structure of otolith is made up of CaCo3 and protein otoline the deposition of both formed translucent and opaque zones alternatively and these growth zones were used to determine the age and growth. Campana and Neilson, 1985 and Campana, 2001, discussed that the otolith based estimation of age is most accurate and reliable other then the hard parts of fish like scale, rays etc, and Beamish and Fournier, 1981 reported when the size of fish is increasing as the size of otolith is also increased.
The growth is a process of size (Weight or length) changes with time and attempt to depict or compare growth must deal with both dimensions. However, comparing growth curves, which link size and time is not straightforward, indeed, depending on one’s definition of ‘slow’ or ‘fast’ growth, one can get into serious contradictions when growth curves cross one another. Kinne, 1960, wrote that” the different in growth rate established in young fish does not persist throughout life.
1.8. Status of Lutjanids in Pakistan
A survey for estimation of stock assessment, distribution and abundance as well as to check Chemical and Physical parameters (salinity, Density, Temperature etc) and
20 hydrographic studies like, water sampling from different depths and eco sounder studies from Northern Arabian Sea (Coastal waters of Pakistan) was carried out in 1984 during 20th January to 2nd February and samples of Lutjanus johnii were collected at 90 meter depth at N 23 50’ E 66 40’ with the help bottom trawl net (IMR.1984” Second Fisheries Resource Survey of Pakistan by Dr. Fridtjof Nansen) Lutjanus johnii was also collected at different locations/ stations Nº 25 6.9 Eº 66 35.20, Nº 23 44. 85 Eº 67 32.52 and Nº 22 59.51 Eº 67 25.36 and Nº 23 0.00 Eº 67 22.35 at different depths from 22 to 34 m, Lutjanus ressulli at Nº 24 19.16 Eº 67 5.92 at 22 meter depth reported by Fanning, et al., 2010, during survey of offshore fisheries resources of Pakistan in 2010.
Both species (L. lutjanus and L. johnii) are locally known as “Hira” (along Sindh Coast) and Kunla or kunalchi (along Baluchistan Coast) Total catch of Snappers from Sindh coast and EEZ was 3,112 m tons in 1999, 2, 111 m tons in 2008 and 3,121 m tons in 2012 reported by Marine Fisheries Department, Government of Pakistan.
Some species of Lutjanus such as Lutjanus johnii, L. Sebae, L. russelli and L. argentimaculatus are cultured in marine water in floating cages in Malaysia, Singapore, China , Thailand Philippine and Pakistan, reported by Doi et al.,1994 and Hussain and khatoon, 2000 recorded that the snappers are lived ranging from 5 m to 500 meter depth , but some are found at about 100 meter depth. Allen, 1985 reported these are marine mostly but some also found in fresh water, commonly lived at tropical at 7 m to 500 meter depth , in juvenile stage some species enter in river waters and soft bottom areas and in this stage they perform vertical migration and found at about 20 to 30 m depth. Snappers are widely distributed at Great Barrier Reef, Chiku River, Red Sea, Prussian Gulf, South China Sea, Bay of Bengal, Gulf of Oman, Somalia, Indonesia, Adaman Sea and Arabian Sea reported by Blaber, 2000.
Generally Lutjanids are well distributed along the coast of Pakistan and represented twenty-nine species belonging nine genera, some are most abundant such as Lutjanus johnii, Lutjanus lutjanus, Lutjanus lunulatus, Lutjanus malabaricus, Lutjanus rivulatus, Lutjanus sebae, Lutjanus bohar, Lutjanus gibbus, Lutjanus lemniscatus,
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Lutjanus fulvus, Lutjanus ehrenbergii, Lutjanus vitta. ,all though there is a general perception of the world fish stock being in steep decline, it is very difficult to measure changes in fish population, and the world wide fish catch does not grow any more in spite of ever more sophisticated technology, suggested that a ceiling has been reached as many problems in marine ecosystem and fisheries have their origin in land practices, problems of over fishing globally developed in 1982 as a new Law of the Sea within the United Sate National Convention .i.e. allows to establishment of exclusive Economic Zone (EEZ), in which coastal state have the sovereign rights to use living resources within a 200 N˚ miles limits, fisheries management has improve a great deal over year due to the following effective policy approaches and new technologies:-
a) The adaptations of a precautionary approach in marine capture Fisheries is increasing reflected in political decision making.
b) The Fisheries Global Information System (FIGIS) developed by FAO, which facilitate better, more systematic and transport exchange of fisheries information between the global, regional, national and local level.
c) Vessel Monitoring System technology (VMS) is making monitoring control and surveillance (MCS).
d) Regional Fisheries bodies in developing countries are become more effective and efficient in fisheries management.
e) International plane of action for the management of fishing capacity (IPAMFC) signed by 120 FAO member state in 1999 and recently design of an international plan of action dealing with illegal, unregulated and unreported (IUU) fisheries.
Very little work has been done on age and growth of Lutjanus sp from Pakistan, Huda and Iqbal, 1994, studied biology of Drepane longmana from Sindh coast. Hoda and Qureshi,1993 discussed fecundity of Mullet Valamugil cunnesius in Karachi. Hoda and Iqbal, 1994, studied the reproductive biology reproductive biology of Drepane longimana (Family; Drapanidae) from Sindh coast, Pakistan.
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1.9. Objectives of the present study
o To define the reproductive biology parameters which included gonad maturation stages, fecundity, monthly variation in maturity stages, size distribution of gonad maturity, size at sexual maturity and oocytes size frequency distribution of Bigeye snapper, Lutjanus Lutjanus and John’s snapper Lutjanus johnii. o To determine the information’s which included size distribution, length weight relationship, linear regression analysis and growth determination using Von Bertalanffy Growth of Bigeye snapper, Lutjanus Lutjanus and John’s snapper, Lutjanus johnii. o To investigate the age and growth parameters and relationships through otoliths and scales analysis of Bigeye snapper, Lutjanus lutjanus and John’s snapper, Lutjanus johnii. o To examine and assess the population dynamics parameters which included growth performances estimation, recruitment pattern, probabilities of captures, maximum length estimation of Lutjanus lutjanus and Lutjanus johnii.
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REVIEW OF LITERATURE
2.1 Taxonomy status and classification of Lutjanidae Leis (2014) discussed taxonomy and systematics of Indo-Pacific fishes specially members of family Lutjanidae, and described the family Lutjanidae contains more than 80 Indo-Pacific species, Just over 50 % of Indo-Pacific lutjanid species have described larvae based on series, the 18 Indo-Pacific lutjanid genera, only Lutjanus contains more than 10 species, and only four additional lutjanid genera contain more than three species and the economically important shore fish family with a similar diversity to the Lutjanidae is the Sparidae. Chu et al. (2013) dicussed Phylogenetic relationships family Lutjanidae (43 species in 11 genera, four subfamilies and two genera of the family Caesionidae), by use of mitochondrial DNA (mt DNA) cytochrome c oxidase subunit I (COI), carried out to infer the relationship between the Indian and western Pacific types of Lutjanus russellii collected from the coast of Peninsular Malaysia and reported that the close phylogenetic relationship between Pinjalo pinjalo and Lutjanus red snappers (Lutjanus malabaricus and Lutjanus sebae) they analyzed the phylogenetic tree of all the Lutjanus species except for the two “types” of L. bohar by inferred using COI and CR supports the monophyly and proposed that P. pinjalo be subsumed into Lutjanus as molecular and morphological evidences have re vealed the close affinity of P. pinjalo with the Lutjanus red snappers.
Gold et al. (2011) discussed the Phylogenetic relationships of 20 nominal species of tropical lutjanine snappers (Lutjanidae) (12 from the western Atlantic, one from the eastern Pacific, and seven from the Indo-Pacific) based on 2206 bp (712 variable, 614 parsimony informative) from three protein-coding mitochondrial genes, included in analysis from two individuals, identified initially as Lutjanus apodus, sampled off the coast of Bahia State in Brazil (western Atlantic), and from three individuals of ‘red snapper’ from eastern Pacific, the hypothesis that western Atlantic lutjanines are derived from an Indo-Pacific lutjanine lineage, phylogenetic hypothesis also indicated that oceans are not reciprocally monophyletic for the species distributed within them. There were three strongly supported clades that included all western Atlantic lutjanines: one included six species of Lutjanus from the western Atlantic, two species
24 of Lutjanus from the eastern Pacific, and the monotypic genera Rhomboplites and Ocyurus (western Atlantic); one that included three, probably four, species of Lutjanus in the western Atlantic; and one that included Lutjanus cyanopterus (western Atlantic) and three species of Lutjanus from the Indo-Pacific.
Rodrigo et al. (2007) discussed the taxanomy and status of family Lutjanidae (Snappers), along the coast of Brazil have resulted in the discovery of many new reef- fish species, including commercially important parrotfishes (Scaridae) and grunts (Haemulidae) and describe a new species of snapper, Lutjanus alexandrei, which is apparently endemic to the Brazilian coast.
Miller and Cribb (2007) analyzed the phylogenetic relationships of 27 species of common Indo-Pacific snappers (Lutjanidae), included species representing four subfamilies, the Caesioninae, Etelinae, Paradicichthyinae, and Lutjaninae and the members of the closely related families Haemulidae, Lethrinidae, Nemipteridae and Sparidae for outgroup comparisons and to explore the relationships between the Haemuloidea, Lutjanidea and Sparidea and discussed the species of Western Atlantic Lutjanids, Lutjanus campechanus, Lutjanus synagris, and Rhomboplites aurorubens, examine their relationships to Indo-Pacific species; and described they formed a well- supported clade nested within Pacific lutjanines suggesting that Atlantic species of Lutjaninae are derived from an Indo-Pacific lineage.
Zhu et al. (2007) studied and observed the phylogenic relationship of Lutjanus through 12S and r RNA studies (Lutjanids) on the basis of (AFPL) Amplified fragment length polymorphism method and discussed the phylogenetic relationship of Lutjanids from China based on analyses of AFLP method through analysis of genome, further reported that the, it has advantages of RAPD and RELP dose not required genetic information of fish.
Salini et al. (2006) reported the phylogenetic relationships of intra- and interspecies were elucidated based on complete cytochrome b and cytochrome c oxidase subunit II (COII)gene sequences from 12 recognized species of genus Lutjanus Bloch in the South China Sea (SCS) and described the monophyly of eight species, (L.malabaricus
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L. russellii, L. stellatus, L. bohar, L. johnii, L. sebae, L. fulvus, and L. fulviflamma) was strongly supported; however, the pairs L. vitta/ L. ophuysenii and L. homogeneity, Erythropterus / Lutjanus argentimaculatus.
Andrade (2003) discussed phylogenatics relationship and distribution of snappers are found at the depth ranging from 6m-450m depth Lutjanus russelli and L. fulvus are found in shallow water only at 10m depth. Lutjanus johnii, L. bohar, L. rivulatus, L. sebae, L. malabaricus, L argentimaculatus are found in intermediate depth of 100 m. While Etelis and peristipomoides species are found in deep water at depth of 100 m- 500m. Posada and Crandall (1998) investigated the morphological characters of Lutjanids and observed the P. pinjalo shares similar morphological characteristics with Lutjanus malabaricus and Lutjanus sebae dorsal fin with XI spines and 13 to 14 soft rays, body depth 2.7 times in standard length, vomerine tooth patch crescentic without posterior extensions, smooth tongue, and total gill rakers ranging from 22 to 23 based on the taxonomic keys of Lutjanidae (Anderson and Allen 2001). Both Lutjanus and Pinjalo have 20 or less gill rakers on the lower limb of the first gill arch, but are separate genera based on the head profile, longitudinal scale row pattern, and the absence or presence of anterior fang-like canines. However, these distinguishing characters are not exclusive as some are shared by a few Lutjanus species.
Nelson (1994) discussed the characters and stuts of family lutjanidae as Lutjanids belongs to the perciformes, commonly known as “snappers”, composed 4 families of 17 genera and 103 species. Sub family Lutjaninae represents about two thirds of the species of family lutjanidae and the species of this family Lutjaninae constitute an important component of the reef fishes in tropical and subtropical latitudes throughout their geographical range. Zhu et al. (1994) dicussed and studied the phylogenatic status and relationship of species of Lutjanidae and Bernatchez and Danzmann (1993) reported congruence between CR and other mitochondrial genes may indicate a lower effect of homoplasy in CR and thus the usefulness of CR for testing phylogenetic relationships between closely related species of Lutjaninae.
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Tashiro (1979) brought workable order of the status of family Lutjanidae the work of Jordan and Swain (1885); Jordan and Fesler (1893) and Jordan and Evermann (1896- 1900) reported uncertainty concerning general snapper (Lutjanidae) taxonomy.
William (1967) discussed the identifaction and characters of Western Atlantic Snappers (Lutjanidae) and described eight (8) genera and twenty seven species (27) and presented key for identification of species.
Shinohara (1966) discussed the status of snappers (family Lutjanidae) and reported the some fishes of family Lutjanidae have phylogenic relationship to the epinephelids.
2.1.1 General Taxonomy status of Lutjanidae
Agriculture and Agri-Food Canada (2013) described the taxonomy status of Lutjanidae as:- Kingdom Animalia Animals Phylum Chordata Chordates Subphylum Vertebrata Vertebrates Super class Osteichthyes Bony fishes Class Actinopterygi Ray-finned fishes, spiny rayed fishes Subclass Neopterygii Neopterygians Infraclass Teleostei Super order Acanthopterygii Order Perciformes Perch-like fishes Suborder Percoidei
Family Lutjanidae Fusiliers, sae perches, sea perches contains 129 valid taxa
Subfamily Apsilinae Subfamily Etelinae Subfamily Lutjaninae Subfamily Paradichthyinae
Moura and Lindeman (2007) and Nelson (2006) reported the family Lutjanidae includes four subfamilies-Etelinae, Apsilinae, Paradichthyinae and Lutjaninae that together encompass 107 species.
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According to Froese and Pauly (2000) the largest subfamily Lutjaninae with six genera which included (Hoplopagrus, Ocyurus, and Rhomboplites) are monotypic genera, the genera Macolor and Pinjalo with two species each and the genus Lutjanus with 66 species.
Fischer and Bianchi (1984) reported 32 species of members of Lutjanidae recorded from Pakistan which included; Lutjanus (family Lutjanidae) have been recorded from Karachi cost included Lutjanus johnii; L.argentimaculatus; L. bohar; L.fluvuflamma; L.gibbus; L.lemniscatus; L.lutjanus; L.erythropterus; L.malabaricus; L sebae; L.vittus; L.bengalensis; L.eherenbergii; L.fulvus; L.kasmira; L.lunulatus; L.rivulatus; L.russelli, L.senguineus; Macolar niger; Paracaesio xanthura; Pinjalo pinjalo; Pristipomoides filamentosus; P.multidens; P.sieboldii; P.zonatus; Aphareus furcatus; A.rutilans; A.virescens. 1. Sub family Paradicichthyninae: with two monotypic genera Symphorus and Symphorichthys. 2. Sub family Etlinae: with five genera (Aphareus, Aprion, Etelis, Pristipomoides and Rhandallichthys) with 18 species. 3. Sub family Apsilinae: with four genera (Apilus, Lipocheilus, Paracesio and Parapristipomoides). 4. Subfamily Lutjaninae: With four genera (Hoplopagrus, Lutjanus, Macolor, Ocyurus, Pinjalo, Rhomboplites).
Russ and Alcala (1989) reported that the genus Lutjanus is represented in the South China Sea (SCS) by approximately 20 indigenous species, which are important economically and are a significant source of food for developing countries around SCS.
Allen and Talbot (1985) discussed taxanomy status of family Lutjanidae belongs to sub order percoidae, is composed of 17 general and 103 species fresh water species. Lutjanids are perch-like fishes, moderately elongated to deep bodies, fairly compressed. Family Lutjanidae devided into (four) subfamilies:- Etelinae – Aphareus, Aprion, Etelis, Pristipomoides, Randallichthys Apsilinae - Apsilus, Lipocheilus, Paracaesio, Parapristipomoides
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Paradichthyinae - Symphorichthys, Symphorus Lutjaninae - Hoplopagrus, Lutjanus, Macolor, Ocyurus, Pinjalo, Rhomboplites
Sub family Lutjaninae: Nostrils on the each side usually not closely related together. Except in genus Lutjanus in which they are close together. Vomerine teeth are present, body moderately elongated to moderately deep. Dorsal fin with XI-XII spines and 10-16 soft rays. Anal fin with III spines and 7- Soft rays. Cuadal fin truncated to fork.
2.1.2 Classification of Lutjanidae
Eschmeyer and Fong (2014) reported the Family Lutjanidae available species 374 in which valid species are 109 and 4 reported in last 10 years (2005-2014) Lutjanus is a genus of snappers found in fuscescens and L. maxweberi ) that only occur in fresh water the Atlantic, Indian and Pacific Oceans. According to the Fish base Family Lutjanidae have 17 Genera and 110 species:-
1. Lutjanus adetti ( Yellow –banded Snapper)(Castelnau, 1873) 2. Lutjanus agennes (African red snapper) (Bleeker, 1863) 3. Lutjanus alexandrei (Brazilian snapper) (Moura & Lindeman, 2007) 4. Lutjanus ambiguus (Ambiguous snapper) (Poey, 1860) 5. Lutjanus analis (Mutton snapper) (G. Cuvier, 1828) 6. Lutjanus apodus (Schoolmaster snapper) (Walbaum, 1792) 7. Lutjanus aratus (Mullet snapper) (Günther, 1864) 8. Lutjanus argentimaculatus (Mangrove red snapper) (Forsskål, 1775) 9. Lutjanus argentiventris (Yellow snapper) (W. K. H. Peters, 1869) 10. Lutjanus bengalensis (Bengal snapper) (Bloch, 1790) 11. Lutjanus biguttatus (Two-spot banded snapper) (Valenciennes, 1830) 12. Lutjanus bitaeniatus (Indonesian snapper) (Valenciennes, 1830) 13. Lutjanus bohar (Two-spot red snapper) (Forsskål, 1775) 14. Lutjanus boutton (Moluccan snapper) (Lacépède, 1802) 15. Lutjanus buccanella (Blackfin snapper) (G. Cuvier, 1828) 16. Lutjanus campechanus (Northern red snapper) (Poey, 1860) 17. Lutjanus carponotatus (Spanish flag snapper) (Richardson, 1842) 18. Lutjanus coeruleolineatus (Blueline snapper) (Rüppell, 1838) 19. Lutjanus colorado (Colorado snapper) (Jordan & Gilbert, 1882) 20. Lutjanus cyanopterus (Cubera snapper) (G. Cuvier, 1828) 21. Lutjanus decussatus (Checkered snapper) (G. Cuvier, 1828) 22. Lutjanus dentatus (African brown snapper) (A. H. A. Duméril, 1861) 23. Lutjanus dodecacanthoides (Sunbeam snapper) (Bleeker, 1854) 29
24. Lutjanus ehrenbergii (Blackspot snapper) (W. K. H. Peters, 1869) 25. Lutjanus endecacanthus (Guinea snapper) (Bleeker, 1863) 26. Lutjanus erythropterus (Crimson snapper) (Bloch, 1790) 27. Lutjanus fulgens (Golden African snapper) (Valenciennes, 1830) 28. Lutjanus fulviflamma (Dory snapper) (Forsskål, 1775) 29. Lutjanus fulvus (Blacktail snapper) (J. R. Forster, 1801) 30. Lutjanus fuscescens (Freshwater snapper) (Valenciennes, 1830) 31. Lutjanus gibbus (Humpback red snapper) (Forsskål, 1775) 32. Lutjanus goldiei (Papuan black snapper) (W. J. Macleay, 1882) 33. Lutjanus goreensis (Gorean snapper) (Valenciennes, 1830) 34. Lutjanus griseus (Grey snapper) (Linnaeus, 1758) 35. Lutjanus guilcheri (Yellowfin red snapper) (Fourmanoir, 1959) 36. Lutjanus guttatus (Spotted rose snapper) (Steindachner, 1869) 37. Lutjanus indicus (G. R. Allen, W. T. White & Erdmann, 2013) 38. Lutjanus inermis (Golden snapper) (W. K. H. Peters, 1869) 39. Lutjanus jocu (Dog snapper) (Bloch & J. G. Schneider, 1801) 40. Lutjanus johnii (John's snapper) (Bloch, 1792) 41. Lutjanus jordani (Jordan's snapper) (C. H. Gilbert, 1898) 42. Lutjanus kasmira (Common bluestripe snapper) (Forsskål, 1775) 43. Lutjanus lemniscatus (Yellow-streaked snapper) (Valenciennes, 1828) 44. Lutjanus lunulatus (Lunartail snapper) (M. Park, 1797) 45. Lutjanus lutjanus (Bigeye snapper) (Bloch, 1790) 46. Lutjanus madras (Indian snapper) (Valenciennes, 1831) 47. Lutjanus mahogoni (Mahogany snapper) (G. Cuvier, 1828) 48. Lutjanus malabaricus (Malabar blood snapper) (Bloch & J. G. Schneider, 1801) 49. Lutjanus maxweberi (Pygmy snapper) (Popta, 1921) 50. Lutjanus mizenkoi (Samoan snapper) (G. R. Allen & Talbot, 1985) 51. Lutjanus monostigma (One-spot snapper) (G. Cuvier, 1828) 52. Lutjanus notatus (Blue-striped snapper) (G. Cuvier, 1828) 53. Lutjanus novemfasciatus (Pacific dog snapper) (T. N. Gill, 1862) 54. Lutjanus ophuysenii (Spotstripe snapper) (Bleeker, 1860) 55. Lutjanus papuensis (Papuan snapper) (G.R.Allen, W. T. White & Erdmann, 2013) 56. Lutjanus peru (Pacific red snapper) (Nichols & Murphy, 1922) 57. Lutjanus purpureus (Southern red snapper) (Poey, 1866) 58. Lutjanus quinquelineatus (Bloch, 1790) (five-lined snapper) 59. Lutjanus rivulatus (Blubberlip snapper) (G. Cuvier, 1828) 60. Lutjanus rufolineatus (Yellow-lined snapper) (Valenciennes, 1830) 61. Lutjanus russellii (Russell's snapper) (Bleeker, 1849) 62. Lutjanus sanguineus (Humphead snapper) (G. Cuvier, 1828) 63. Lutjanus sebae (Emperor red snapper) (G. Cuvier, 1816) 64. Lutjanus semicinctus (Black-banded snapper) (Quoy & Gaimard, 1824) 65. Lutjanus stellatus (Star snapper) Akazaki, 1983 66. Lutjanus synagris (Lane snapper) (Linnaeus, 1758) 67. Lutjanus timoriensis (Quoy & Gaimard, 1824) (Timor snapper)
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68. Lutjanus viridis (Blue and Gold snapper) (Valenciennes, 1846) 69. Lutjanus vitta (Brown stripe red snapper) (Quoy & Gaimard, 1824) 70. Lutjanus vivanus (silk snapper) (G. Cuvier, 1828)
Fish base (2014) reported following species of Lutjanus:-
Year Scientific Name English Name Distribution Max Length cm 1775 Lutjanus Mangrove red snapper Indo-West Pacific 150 TL argentimaculatus 1790 Lutjanus bengalensis Bengal snapper Indian Ocean 30 TL 1830 Lutjanus biguttatus Two-spot banded Indo-Pacific 25 TL snapper 1830 Lutjanus bitaeniatus Indonesian snapper Eastern Indian 30 TL Ocean 1775 Lutjanus bohar Two-spot red snapper Indo-Pacific 90 TL 1842 Lutjanus carponotatus Spanish flag snapper Indo-West Pacific 40 TL 1828 Lutjanus decussatus Checkered snapper Indo-West Pacific 35 TL 1869 Lutjanus ehrenbergii Blackspot snapper Indo-West Pacific 35 TL 1790 Lutjanus erythropterus Crimson snapper Indo-West Pacific 81.6 FL 1775 Lutjanus fulviflamma Dory snapper Indo-Pacific 35 TL 1801 Lutjanus fulvus Blacktail snapper Indo-Pacific 40 TL 1775 Lutjanus gibbus Humpback red snapper Indo-Pacific 50 TL 1959 Lutjanus guilcheri Yellowfin red snapper Indian Ocean 60 TL 2013 Lutjanus indicus Indian Ocean 22.6 SL 1792 *Lutjanus johnii John's snapper Indo-West Pacific 97 TL 1775 Lutjanus kasmira Common blue stripe Indo-Pacific 40 TL snapper 1828 Lutjanus lemniscatus Yellowstreaked Western Indian 65 TL snapper Ocean 1797 Lutjanus lunulatus Lunartail snapper Indo-West Pacific 40 TL 1790 *Lutjanus lutjanus Bigeye snapper Indo-West Pacific 35 TL 1831 Lutjanus madras Indian snapper Indo-West Pacific 30 TL 1801 Lutjanus malabaricus Malabar blood snapper Indo-West Pacific 100 TL 1828 Lutjanus monostigma One-spot snapper Indo-Pacific 60 TL 1790 Lutjanus quinquelineatus Five-lined snapper Indo-West Pacific 38 TL 1828 Lutjanus rivulatus Blubberlip snapper Indo-Pacific 80 TL 1830 Lutjanus rufolineatus Yellow-lined snapper Indo-West Pacific 30 TL
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1849 Lutjanus russellii Russell's snapper Western Pacific 50 TL Lutjanus sanguineus Humphead snapper Western Indian 1828 100 TL Ocean 1816 Lutjanus sebae Emperor red snapper Indo-West Pacific 116 FL 1824 Lutjanus timoriensis Timor snapper Western Pacific 50 TL Lutjanus vitta Browns tripe red 1824 Indo-West Pacific 40 TL snapper 1931 Macolor macularis Midnight snapper Western Pacific 60 TL Macolor niger Black and white 1775 Indo-Pacific 75 TL snapper 1962 Paracaesio sordida Dirty ordure snapper Indo-Pacific 48 TL 1869 Paracaesio xanthura Yellowtail blue snapper Indo-Pacific 50 TL
Kritsky (2012) defined the status of Lutjanids from the Red Sea, Persian Gulf, the Indo-west and eastern Pacific Ocean, the Gulf of Mexico and Caribbean Sea, Twenty one of 29 species of snappers (Lutjanidae) were parasitized by 16 new and 11 previously described species of Euryhaliotrema, alongwith specimen of an unidentified species of Euryhaliotrema and yellowbanded snapper, Lutjanus adettii, off Australia and two unidentified species of Euryhaliotrema , L. argentiventris, in the eastern Pacific Ocean off Panama. L. sebae from Australia, L. analis from the Gulf of Mexico, L. aratus and L. colorado from the eastern Pacific Ocean, L. cyanopterus from the Gulf of Mexico and Caribbean Sea, L. mahogoni from the Caribbean Sea, and L. rivulatusfrom New Caledonia were uninfected with species of the genus.
Gold et al. (2011) discussed the phylogenetic relationships among 20 nominal species of tropical lutjanine snappers (Lutjanidae) (12 from the western Atlantic, one from the eastern Pacific, and seven from the Indo-Pacific) from three protein-coding mitochondrial genes and included in the analysis were DNA sequences from two individuals, identified initially as Lutjanus apodus, and from three individuals labelled as ‘red snapper’ in the fish market in Puerto Armuelles, Panama (eastern Pacific) they also described the phylogenetic hypothesis and the oceans where lutjanines are distributed (western Atlantic, eastern Pacific, and Indo-Pacific) are not reciprocally monophyletic for the species distributed within them.
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2.2. Characters and species of Lutjanidae
2.2.1 Characters of Lutjanidae Initiative (2013) reported that the Lutjanids are elongated bodies, large mouths, sharp canine teeth, and blunt or forked tails, usually rather large, many attaining a length of 60–90 centimeters (2–3 feet) according to the encyclopedia the snappers are carnivorous fish have valuable and well-regarded food. Some, such as the dog snapper (Lutjanus jocu) of the Atlantic, may contain a toxic substance and cause ciguatera, a form of poison. The better known species of snappers include the emperor snapper (Lutjanus sebae), a red and white Indo-Pacific fish; thegray, or mangrove, snapper (Lutjanus griseus), a gray, reddish, or greenish Atlantic fish; the yellowtail snapper (Ocyurus chrysurus), a swift-moving Atlantic species with a broad, yellow stripe from the nose to the wholly yellow tail; and the red snapper (Lutjanus campechanus), a bright-red fish (one of several red-coloured snappers) famed as food and found in rather deep Atlantic water. They further described the members of family Lutjanidae, mainly marine, but with some members inhabiting estuaries, feeding in fresh water, tropical and subtropical inhabit ,can grow to about 1 m (3.3 ft) in length, mostly feed on crustaceans or other fish, and few are plankton-feeders, they live at depths reaching 450 m (1,480 ft).
According to Froese et al. (2013) The body of snappers are perch like and generally large in size, mouth terminal (towards the bottom of the head) Often silvery or shinny/ reflective scales, steep forehead and gentle sloping back towards tail, actively swimming on or above the reef some growing up to 3ft, the common genera of family Lutjanidae are Ocyurus and Lutjanus.
Jawad et al. (2012) discussed asymetry in some morphological characters of Lutjanus ehrenbergii (Petters,1869) (Family Lutjanidae) collected from Bandar Abbas to estimate the Fluctuating asymmetry (FA) in Lutjanus ehrenbergii the number of rays in pectoral fins and measurement of three body morphometric characters, i.e. preorbital length, postorbital length and orbital diameter, were determined on both sides of the body in 150 individuals from one population of Lutjanus ehrenbergii collected in the coastal waters of Bendar Abbas City, Iranian Coasts, Persian Gulf.
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Allen (1985) discussed the characters of family Lutjanidae as they are typical perch- like, oblong in shape, moderately compressed (size to160 cm). Eye usually moderate. Premaxillae usually moderately protrusible (fixed in Aphareus and Randallichthys). Two nostrils on each side of snout. Mouth terminal and fairly large. Maxilla slipping for most or all of its length under lacrimal when mouth closed. Supramaxilla absent. Jaws usually with more or less distinct canines (canines absent in Aphareus, Parapristipomoides, and Pinjalo). Vomer and palatines usually with teeth. Pterygoids usually toothless. Cheek and operculum scaly; maxilla with or without scales; snout, lacrimal, and lower jaw naked. Opercular spines 2. Branchiostegal rays 7. Dorsal fin single, spinous portion sometimes deeply incised posteriorly where it joins soft portion. Caudal fin truncate to deeply forked. Dorsal fin with X to XII spines and 10 to 19 soft rays. Anal fin with III spines and 7 to 11 soft rays. Principal caudal-fin rays 17 (9 in upper lobe, 8 in lower lobe of fin). Pectoral-fin rays 14 to 19. Pelvic fins with I spine and 5 soft rays. Scales moderate to rather small, ctenoid. Lateral line complete. Pelvic axillary process usually well developed.Vertebrae 24 (10+14). Colour: highly variable; mainly from red through yellow to blue; often with blotches, lines, or other patterns. Allen and Talbot (1985) described the biological characters and habitat of Lutjanids as they found worldwide in warm seas and reported the juveniles of several species of Lutjanus enter estuaries and the lower reaches of fresh-water streams, few Indo- Pacific species of Lutjanus are bottom-associated, found from shallow inshore areas to 500 m depths, active predators, mostly nocturnal, feed on fishes, crustaceans (especially crabs, shrimps, stomatopods, lobsters), molluscs (gastropods, cephalopods), and pelagic urochordates, members of family Lutjanidae are long-lived, slow-growing with relatively low rates of natural mortality and with considerable vulnerability to overfishing, important to artisanal fisheries,
Nelson (1984) described the characters of family Lutjanidea as the Dorsal fin continuous or slightly notched. Spines in dorsal fin 10-12; soft rays 10-17. Three spines in anal fin; soft rays 7-11. Pelvic fins originating just behind pectoral base. Mouth moderate to large; terminal. Jaws bearing enlarged canine teeth. Palatine teeth small. Vomer usually with small teeth. Maxilla covered by preorbital with the mouth closed. Branchiostegal rays 7. Vertebrae 24 (10 + 14). To about 1 m maximum length, Having Perch-like body shape with large terminal mouth towards the bottom of the 34 head, often silvery or with shiny / reflective scales and steep forehead and are well known to reef fish community, found commonly across coral reef from shallow to deeper waters, generally large in sloping back towards tail with some growing 3 ft (Total Length), Swim actively on or above the reef ,found often in school, but larger individual may be solitary times common genera are Ocyurus and Lutjanus. Fischer and Bianchi (1984) discussed the diagnostic charaters of Lutjanus lutjanus are; Dorsal spines (total):10- 12; Dorsal soft rays (total): 12; Anal spines: 3; Anal soft rays: 8. Dorsal profile of head gently sloped. Preorbital bone very narrow, much less than eye diameter. Preopercular notch and knob poorly developed. Scale rows on back rising obliquely above lateral line. Generally silvery white, with a broad yellow stripe running along the side from the eye to the caudal fin base. A series of faint narrow yellow horizontal lines is on the lower half of the body. The fins are pale yellow to whitish Body depth 2.9-3.3 in SL. The bigeye snapper, Lutjanus lutjanus, is a species of snapper native to the Indian Ocean and the western Pacific Ocean. It inhabits offshore coral reefs at depths from near the surface to 96 m. This species is mostly silver in color with a yellow stripe along the side and fainter yellow lines on the lower half of the body. Fins are yellowish to whitish. It can reach a length of 35 cm (14 in). It is much sought-after by commercial fisheries. Allen (1985) reported the dorsal profile of head steeply sloped. Preorbital width equal to eye diameter or larger. Preopercular notch and knob poorly developed. Scale rows on back parallel to lateral line, center of each scale often with a reddish-brown spot, giving an overall appearance of series of horizontal lines on side of body. Generally yellow with a bronze to silvery sheen, shading to silvery white on belly and underside of the head. A large black blotch mainly above the lateral line below the anterior dorsal-fin rays.
Talwar and Kacker (1984) discussed morphological characters of Lutjanus Lutjanus, the longitudinal rows of scales above lateral line appear to rise obliquely to dorsal profile, those in front of and below anterior part of spinous dorsal fin sometimes parallel to lateral line.Scales on head beginning above middle of eyes or nearly so, temporal region scaly. Preopercular notch slightly developed vomerine teeth in a triangular or arrow shaped patch. Dorsal fin with 10 spines (rearly 9 or 11), 6 or more rows of scales between lateral line and medium dorsal spines. No dark lateral band from eye to caudal fin. Scales row 6 between lateral line and medium dorsal spines,
35 preorbital and suborbital bones rugose and described as the Body fusiform, slender (greatest depth 2.9 to 3.3 times in standard length). Dorsal profile of head gently sloped; pre orbital bone very narrow, much less than eye diameter; preopercular notch and knob poorly developed; vomerine tooth patch triangular, with a medial posterior extension; tongue with a patch of granular teeth; gill rakers on lower limb of first arch (including rudiments) 17 to 19, total rakers on first arch 24 to 26. Posterior profile of dorsal and anal fins angular, the scale rows on back rising obliquely above lateral line.
Anderson (1967) reported Lutjanids are spiny-rayed species having a typical "fishlike" appearance. Western Atlantic lutjanids show the following characters: head large, without a bony suborbital stay; mouth moderate to large, usually terminal; premax illaries moderately protractile; maxillary long, without a supplemental bone, slipping under edge of suborbital (preorbit~l) for most of its length when mouth is closed; vomer and palatines usually with teeth; gills 4, a slit behind fourth; pseudobranchiae large; gill membranes separate, free from isthmus; dorsal fin single- sometimes deeply notched--or sometimes divided into 2 fins; dorsal fin usually with 10 to 12 spines and 10 to 14 50ft rays (X to XII, 10 to 14); anal fin with 3 spines and 7 to 950ft rays (III, 7 to 9); pectoral fin usually with 15 to 18 50ft rays (15 to 18); pelvic fins thoracic with 1 spine and 550ft rays (I, 5); pelvic fin with an accessory scale at base; caudal fin with 17 principal fin rays (9+8);and vertebrae usually 24 (10 precaudal + 14 caudal).
2.3. Reproductive Biology
Courtney et al. (2013) studied the reproductive biology and life history of red snapper (age 2-4) and investigated the red snapper spawn several time in season and producing many millions of eggs over a life span. Very few eggs survive to adulthood.
Ken et al. (2013) discussed the reproductive analysis and length-dependent relationships of Lutjanus biguttatus (Lutjanidae) from Papua New Guinea investigated through a simple, inexpensive method for histological analysis of gonads, with reproductive biology of the small snapper Lutjanus biguttatus.
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Indian biodiversity portal (2013) reported reproductive biology of L. fulviflamma (Dory snapper) and described the L. fulviflamma matures at size of 20 - 25cm and dioecism mode and external reproduction observed.
Joshua et al. (2013) strategy of early reproduction (age 2-4) and produced many millions of eggs over a life span and reported that that the majority of eggs are laid in 50-100 m of water and drift to shallower water before hatching. Eggs and larvae remain pelagic (drifting freely in open water neither close to the bottom nor the shore) until metamorphosis and settlement at close to 27 days and 18 mm total length.
Cezar et al. (2012) observed the reproductive aspects of lutjanus alexandrei (Brazilian Snapper) render development of spermatogenesis cells and Oocytes at the first sexual maturity and fecundity, further they calculated the age and growth of fish in relation of mature specimens.
Heyman and Kobara (2011) provides details on the timing and location of spawning aggregations snappers and groupers and investigated they then spawn in aggregations at predictable times and places, releasing pelagic eggs that are fertilized in the water column the eggs metamorphose into larvae after 12-24 hours, swim in the plankton for 1 to three weeks and then settle as juveniles into protected nursery habitats, generally mangroves and seagrass. Many variations observed on this general pattern, commercially important groupers and snappers in Belize such as mutton snapper, cubera snapper, yellow tail snapper, Nassau grouper, black grouper, yellowfin grouper, tiger grouper.
Alpina Begossi et al. (2011) studied the biology and reproductive behavior of five species of snappers (Lutjanidae), including Lutjanus analis, Lutjanus synagris, Lutjanus vivanus, Ocyurus chrysurus, and Romboplites saliens at five sites along the northeast (Riacho Doce, Maceió in Alagoas State, and Porto do Sauípe, Entre Rios at Bahia State) and the southeast (SE) Brazilian coast. Most of the snappers reached sexual maturity during the spring (September-December) the knowledge on reproductive periods of species of snappers is an useful information towards fishery management, in this view they collected the interviews of some fishermen know about the reproduction species (a half does not know about the species) reproductive
37 behavior of considering the site where there is the highest occurrence and diversity of species of snappers on artisanal landings.
Gerhardingher et al. (2009) investigated that the no spawning aggregations of the mutton snapper have been recorded in Brazil and reported the anecdotal reports of large schools of the cubera snapper Lutjanus cyanopterus are not uncommon.
Fry et al. (2009) studied the reproductive biology of red snapper that the spawning in Lutjanus sp occurrs throughout the year in northern Australia and eastern Indonesia, they observed at least 10–30% of females and 40–80% of males were in ripe or spawning condition in most months the spawning peak from July to December (L. erythropterus) and September to March (L. malabaricus).
Boza-Abarca et al. (2008) discussed reproductive biology of spotted snapper from Gulf of Nicoya (Costa Rica) in cage culture during one year to produce broodstock, and the maturation stage was monitored every month. Broodfish of 60–100 g (76.76 ± 14.47 g, mean ± SD) body weight and 16–20 cm (18.60 ± 1.8 cm, mean ± SD) total length were reared in cages (4 × 4 × 3 m, 48 m3) at a density of 8 fish m–3.
Longenecker et al. (2012) decribed the reproductive biology of Lutjanus biguttatus and relationship between reproductive analysis and length dependent relationships were observed in Lutjanus biguttatus from Papua New Guinea.
Longenecker et al. (2008) discussed low cost techiniques for describing the population structure of reef fishes and during Hawaii Biological survey.
Ogle and Lotz (2006) studied the reproductive status of Lutjanus guttatus in Panama in captivity by use hormone induction and observed that the L.guttatus spawned spontaneously. Heyman et al. (2005) discussed spawning behavior of Cuban snapper lutjanus cyanopterus further studied the biology, maturity, fecundity, age and growth and mortality of Grey snapper from indo Pacific Ocean and reprted that the mutton snapper spawn from March to June further they described reproductive biology of cubera snapper consistently formed seasonal spawning aggregations in relation to location, photoperiod, water temperature and lunar cycle, and reported that the
38 spawning was cued by time of day but not tides of mostly reef associated marine fishes, several deep water (>100m) and status of Cubera snapper Lutjanus cyanopterus and given detail description as aggregated to spawn at Gladden Spit, a salient subsurface reef promontory seaward of the emergent reef and near the continental shelf edge of Belize. They further described that the spawning aggregations typically formed 2 days before to 12 days after full moon from March to September 1998-2003 within a 45 000 m2 reef area. And observed the Peak abundance of 4000 to 10 000 individuals between April and July each year, while actual spawning was most frequently in May. Further spawning was observed consistently from 40 min before to 10 min after sunset within a confined area 1000 m2.
Hay (2005) studied the reproductive biology of Golden snapper (Lutjanus johnii) sex, maturation regarding length, weight, age and otolith (ear bones) from survey and commercial fisherman at NT coast. Ibarra et al. (2004) reported some Lutjanid species have been spawned spontaneously or artificially in captivity; however, spawning can be very difficult and larvae die in the first few days after hatching or during metamorphosis, and the survival rate is low.
Kiso et al. (2003) investigated reproductive biology of Lutjanus johnii in the Matang mangrove estuary on the west coast of Peninsular Malaysia from October 1998 to January 2000, immature stage of L.johnii observed in total length varied from 3.4 to 21.1 cm.
Kamaleie (2001) studied reproductive biological features of Lutjanus johnii such as spawning season, sex ratio and reproductive biology of L. johnii on the basis of GSI and observed the female specimens were mature at 44 cm with a maximum fecundity observed in the month of July 2539592 and the sex ratio was observed 1.23 female to 1 male.
Domeier and Colin (1997) discussed the spawning behavior of cubera snappers (Lutjanus cyanopterus) form spawning aggregations and they observed three aggregations off the coast of south Florida where water depth was about 67-85 m, and another two off the coast of Belize at water depths of 10 – 30 m observed during the 39 months of June and July and reported the Indo-West Pacific sail- fin snappers (Symphorichthys spilurus) aggregate to spawn along seaward reefs, and discussed the spawning aggregations of the Indo-West Pacific species of mangrove red snapper (L. argentimaculatus), two-spot red snapper (Lutjanus bohar), humpback red snapper (L. gibbus), black and white snapper (Macolor niger) and the Chinaman fish (Symphorus nematophorus).
Arara and Ntiba (1997) discussed reproductive biology of Lutjanus fulviflamma (Forsskål,1775) in Kenyan inshore marine waters, the L. fulviflamma has one prolonged spawning season from November/December, till April/May by using volumetric and histological techniques,oocytes recrudescence in the ovary isasyncronous.
Zhao and McGovern (1997) discussed the reproductive biology of and investigated maturation at each length class and age for each sex, length, and sex ratio of vermilion snapper according to depth the sex ratio of vermilion snapper was dependent upon latitude and gear type but was generally independent of water depth, fish length, and sampling years, significantly different among latitudes.
Caveriviere (1996) documented frequent spawning of L. agennes, aggregate African red snappers up to 2,500 large (840-1160 mm fork length) (L. agennes) off the Guinea Gulf coast on western Africa.
Domeier et al. (1996) characterized two different spawning strategies for inshore snappers and described these are medium sized, schooling species do not migrate or form spawning aggregations, while large and solitary species do migrate and form aggregations during the spawning season, the adult populations of deeper water species (>100 m), which are normally found off-shore, on the continental slope, apparently move little or not at all to spawn.
Pauly et al. (1996) discussed the reproduction of spawning behavior of Lutjanid by use AUXIM as tolls for spawning and life history of fish in natural and artificial habitat.
40
Cuellar et al. (1996) studied the reproductive seasonality, maturation, fecundity, and spawning frequency of the vermillion snapper Rhomboplites aurorubens in Southern USA during MARMAP survey.
Manickchand (1996) discussed reproduction, size at maturation, spawning time of Lutjanus purpures Caribbean or Southern Red snapper at Trinided and Tobago.
Gomez et al. (1996) studied the reproductive aspects and biomass of Lutjanus vivanus (Yellow eye snapper) from Hermanos Islands, Eastern Venezuela and discussed the population size structure and reproduction (sex ratio, sexual maturity) of yellow eye snapper and observed mature specimens in the start of May with gonadal activity in May- June and August November. At about 565mm (TL) 50% were found able to reproduce and size at maturity was significantly different in male and female.
Wilson et al. (1994) studied the reproductive biology, life history gape, age , growth and of red snapper (Lutjanus argentimaculatus), swor fish (Xiphias gladius) and red drum (Sciaenops ocellatus) from northen Gulf of Mexico.
Carter and Perrine (1994) observed mass spawning aggregations of dog snapper (Lutjanus jocu) off central Belize (about 32 km from the coast line).
Garcia-Cagide et al. (1994) reported the individual female of mutton snapper is a batch spawner, releasing eggs a number of times in a single month, but spawning only one month each year.
Hamamoto et al. (1992) studied the spawning aggregation in L. stellatus in aquarium, fish formed a spawning aggregation of more than 100 individuals every night, from 2000-2300 hrs from mid May to mid June with water temperatures ranging from 24 to 26 °C, forming small schools with several males following a single female.
41
West (1990) discussed reproductive biology of Lutjanids and stages of ovary development through histological study of fish gonds based on the most advanced non-atretic cell type present.
Everson et al. (1989) described the juveniles of lutjanids remain on nursery grounds usually for a period of 2 to 4 years, until they reach maturity and then move to other areas joining the adult population, lutjanids reach their maturity at about 43 to 51 % of the maximum total length, with males maturing at a slightly smaller size than females.
Moran (1988) studied the reproductive biology of red snappers (L. campechanus) as they spawn away from reefs and at a depth of 18 – 37 m over a sand bottom with little relief.
Bouhlel (1988) discussed reproductive biology of Lutjanus lutjanus (Lutjanidae) and observed the L. lutjanus Mature at about 12 cm (total length) are non-guarder, open water and substratum spawnner with external fertilization and pawn during March and November in the Gulf of Aden and off East Africa respectively, and from January to June in the Gulf of Suez.
Grimes (1987) described the Lutjanids are exhibit summer spawning, whereas insular populations and species reproduce in a more or less continuous pattern with peak activity in the spring and fall they are diocious and gonochoristic and described that the Lutjanids have separate sexes and the sexual differentiation remains constant throughout their life span, batch spawners with individual female spawning several times during the year, spawn generally at night near open water and its time is coinciding with spring tides at new and full moons, ova eggs are pelagic, spherical in shape.
Bortone (1986) documented reproductive biology of yellowtail snappers (Ocyurus chrysurus) spawn in groups usually migrating offshore during the spawning season and reported that lane snappers (Lutjanus synagris) form spawning aggregations in Cuba, which migrate against strong currents and spawn where water depth is 30-40 m.
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Allen (1985) reported snappers spawn apparently at night, on some occasions coinciding with spring tides. Courtship terminates in a spiral swim upward, with gametes released just below the surface. Eggs and larvae identified as lutjanid are pelagic.
Thresher (1984) discussed key of reproductive feature of several species Lutjanus in offshore dwelling and described the Lutjanids select offshore areas along outer reef to form seasonal spawning aggregations in the week or so prior to the full moon and reported two areas of concentrated spawning activity for Lutjanus campechanus off the northern coast of Florida also investigated the Lutjanids is batch spawners with individual females generally spawning several times during the year.
Suzuki and Hioki (1978) observed first record of the spawning behavior, egg and larvae of Lutjanus kasmira in an aquarium the fish usually aggregate during the spawning season in a small scholl in bottom near corner, the male attract the female in small school and he peak and push her belly with his snout they also studied spawning behavior and early life history of Lutjanus kasmira for first 5 days after hatching from aquarium and given basic data for reasoning and hatching of larva of Lutjanids.
2.3.1 Gonad maturation stages
Simone (2010) studied the gonadal maturity of Lutjanus analis (mutton snapper) and observed the females exhibited four different gonadal stages: early maturation, ripe, spent and resting. In Early maturation thin gonadal wall, with well organized ovarian lamellae was found and the ovary presents projections of the gonadal wall for its interior promoting sustainability to inner lamel-lae as well as inside the lamellae oocytes in different stages of pre-vitellogenic growth (gonium, chromatin nucleolus and perinucleolus stage) where observed. In ripe stage gonadal wall reduced, lamellae is well organized and inside ,the oocytes in pre-vitellogenic and vitellogenic growth with higher predominance on the yolk globule stage.In spent gonadal wall quite slim, with lamellae totally disorganized and with oocytes in pre-vitellogenic and vitellogenic growth pre-senting a higher number and residual oocytes in vitellogenic
43 growth in reabsorption and resting the gonadal wall is slim, with well organized ovarian lamellae, inside the lamellae there were oocytes in pre-vitellogenic growth.
Piñón et al. (2009) studied the reproductive cycle of female yellow snapper Lutjanus argentiventris (Pisces, Actinopterygii, Lutjanidae) in the SW Gulf of California they discussed the gonad stages, spawning seasonality and length at sexual maturity of Lutjanus sp.
Kadison (2006) found relation between the presence of dog snapper aggregations and lunar phase on the Grammanik bank with densities peaking between the full and third quarter moon. Botero-Arango et al. (2005) observed the Induction of gonadal maturity in the mutton snapper Lutjanus analis (Pisces:Lutjanidae) by application of artificial phototermal conditioning cycle and studied that the artificial photothermal cycle applied to be effective to unblock and stimulate gonadal development of the captive of Lutjanus analis.
Dumas et al. (2003) observed gonadal maturation in captivity through hormone induced spawning of the Pacific red snapper Lutjanus peru and observed the mature females showing vitellogenic oocytes with diameters over 400 μm and at the time of the second injection, males were also injected (500 IU/kg body weight).
Claro and Lindeman (2003) studied gonad maturation of Mutton snapper, at thirteen reproductive places on the Cuban shelf, where recorded the spawning,varied between April to September, the observed peak spawning at all sites was in May or June, they observed the maturity stages of Mutton snappers (Lutjanus analis) the females analyzed exhibited four different gonadal stages, early maturation, ripe, spent and resting further the early maturation is characterized by thin gonadal wall, with well organized ovarian lamellae, ovary presents projections of the gonadal wall for its interior promoting sustainability to inner lamellae, inside the lamellae are oocytes in different stages of pre-vitellogenic growth (gonium, chromatin nucleolus and perinucleolus stage) they further observed the rare oocytes on yolk globule stage,during ripe the gonadal wall is reduced, lamellae is well organized and inside there are the oocytes in pre-vitellogenic and vitellogenic growth with higher predominance on the yolk globule stage and hydrated oocytes were also observed,in
44 spent gonadal wall is quite slim, with lamellae totally disorganized and with oocytes in pre-vitellogenic and vitellogenic growth presenting a higher number and residual oocytes in vitellogenic growth in reabsorption. Brown bodies were observed in some gonads and resting the gonadal wall is slim, with well organized ovarian lamellae, inside the lamellae there were oocytes in pre-vitellogenic growth.
They investigated four different gonadal stages (III, IV, V and VI) in male specimens, during stage III gonadal wall are reduced, with organized seminiferous lobules, constituted by cells on stages of spermatogonia, primary and secondary spermatocytes and spermatids. More spermatid cells were observed on the seminiferous lobule. In stage IV gonadal wall are thin with organized seminiferous lobules, presence of cells on stage of spermatogonia, primary and secondary spermatocytes, spermatids and few spermatozoids. More spermatid cells than in the stage III were observed on the seminiferous lobule. In stage V gonadal wall are quite slim with slightly organized seminiferous lobules, presence of cells on stage of spermatogonia, primary and secondary spermatocytes, spermatids and spermatozoids. Spermatozoids were found in the whole lobule and in the stage VI the gonadal wall have quite organized seminiferous lobules, constituted by all stages cells, predominating the spermatogonians. Interstitial cells, blood vases and Sertoli cells were observed in the testes.
Emata (1999) investigated maturation stages and induced spawning in of Lutjanus argentimaculatus at floating cages at SEAFDEC/ AQD’s at Guimaras and hatching rate of fish 43-81% were observed from wild collected fishes.
Sheaves (1995) discussed maturation of the Lutjanid and serranid fishes in tropical estuaries and of four species of serranid and Lutjanus ,Epinephalus coides .Epinephalus malabasicus lutjanus russelle and lutjanus argentimaculatus during the study they observed the juvenile and adults having mature gonads with the comparison of age size and maturity stages.
Leis (1987) observed maturation of Cubera snapper the eggs were 78 mm in diameter at fertilization (similar in size tothose of other lutjanids egg density within the clouds,
45 gamete clouds produced by cubera snapper spawning in this relatively oligotrophic environment contain 2-3 million proteinrich eggs, and form the base of temporary patch pelagic ecosystems that arefed on by a variety of species.
2.3.2 Gonadal Somatic Index
Cappo et al. (2013) discussed the preliminary analysis of monthly mean gonadosomatic index (GSI) values (percentages) of L. johnii was made to estimate birth months with measurements of gonad weight available for 176 eastern fi sh. First, WW estimates were calculated from FL (LF) measurements using this equation.
Nanami et al. (2010) calculated GSI of Lutjanids in ishigaki island and associated water areas of Ishigaki /Island okinawawa by using the formula gonad wt (g) / whole wt (g) – wt (g) x 100and defined reproductive biological activities of checkered snappers lutjanus decussates, observed post follicular stages during the study and at last quarter moon time high GSI were found and observed from June to September.
Yang and Liu (2010) studied the gonadal development in Lutjanus sanguineus, where Gonadal somatic Index (GSI) decrease from June to July followed by a slight increase in August and remained at lower levels for several months, changes in GSI of the male was basically similar to that of the female, annual changes in hepatosomatic index (HSI) of male and female Lutjanus sanguineus were observed similar and the highest in March (1.73% and 1.71% in male and female, respectively) the correlation between GSI and HSI in the female also calculated as negative except from June to August, but in male it was positive from May to December. The occurrence rate of spermatogonium in testicular and ovary cells of the phase II and HI were similar to the annual changes in GSI of the male and female during the study the testicular development was divided into 5 stages: spermatogonium, spermatocyte I, spermatocyte II, spermatid and sperm, the testis was developed in the early stage IV. Oogonium, oocyte of the phase II and oocyte of the phase HI were found in the female L. sanguineus, but with reference to the anatomical character, the ovary was developed in the stage II.
46
Heupel et al. (2009) calculated the Gonadosomatic index (GSI = gonad weight / W × 100) of Lutjanids, providing a relative measure of reproductive stage, reproductive stage assessed by macrosexing or histological analysis.
Adams (2003) discussed reproductive biology and provides a out line of procedure for histological sections of fish taken from all gonads.
Heyman and Kjerfve (2000) investigated spawning pettern and GSI of Cubera snapper, eggs hatch 17-20 h after spawning at ending the period of passive transport, during the period fate of aggs is influenced by cometing forces and during the period of lightlocal wind the eggs are transported towards the offshore and entrained in cyclonic meso scaleeddies that characteristically move south and eastward toward Honduras.
Arara (1997) studied gonado somatic index (GSI) of brown meager (Sciaena umbra) in eastern Black Sea, Turkey, reproductive biology and gonad maturation of dory snapper at western Indian Ocean and the seasonal development of sea surface temperature.
Williams and Devid MeS (1994) discussed the GSI of Lutjanids and investigated they spawn spherical, pelagic eggs ranging in diameter from 0.65 to 1.02mm, with the majority single colourless to slightly yellowish oil droplet of 0.12 to 0.20mm diameter is present. Incubation times range from 171036 hours depending on species and incubation temperature.
Sadovy (1987) discussed GSI with the additional features of gonads of fish used in histological staging included the presence of brown bodies, atretic oocytes, vascularisation, and the relative thickness of the gonad wall, all of which may indicate prior spawning Ovaries and testes were classified into developmental stages Females were classified into five stages: Immature, Resting, Ripe, Running Ripe and Spent.Males were classified into three stages: Resting, Ripe and Spent.
2.3.3 Size at Sexual maturity
47
Frose et al. (2013) perovides the details regarding size at sexual maturity of L .johnii at 39cm length and spawning has been reported during September in the Andaman Sea.
Luna et al. (2011) discussed the reproductive biology of fishes and reported size at sexual maturity of Lutjanus Lutjanus mature at 12 cm, where spawning reported durin the months of March and November in the Gulf of Adan and off East Africa and from January to June in the Gulf of Suez. Alpina Begossi et al. (2011) observed the reproductive biology of five snapper species that were most frequently collected (Lutjanis analis, L. synagris, L. vivanus, Osciurus chrysurus, and Romboplites aurorubens) were caught at relative early stages of maturity, Lutjanus analis, in Copacabana, were caught between 350-450 mm; L. synagris, in Bertioga were caught between 350-450 mm and between 470-520 mm in Paraty, and in Riacho Doce, the fish were at sizes ranging between 240-300 mm. L. vivanus, in Porto Sauípe, was caught between 300-400 mm;Ocyurus chrysurus, in Porto Sauípe, was between 350-400 mm; and Romboplites aurorubens, in Porto Sauípe, ranged between 300-350 mm. Bryan et al. (2011) discussed the life history characteristics of silk snapper, queen snapper, and redtail parrotfish studied and summarized to estimate of length- and age-at-maturity from several studies Length-at-maturity represents 50% of population that is mature, evaluat the maturity of gonad tissues in relation to length have provided a range of length-at-maturity estimates between 267mm and 600mm.
Zhu et al. (2011) investigated the Size at Sexual Maturity of Bigeye Tuna Thunnus obesus (Perciformes: scombridae) in the Tropical Waters through five common models were used for estimating the parameter L50 and stated that the proportions of bigeye tuna reach maturity in the stock is an important reference for decision making in fisheries management. The size at 50% sexual maturity (L50) of bigeye tuna, Thunnus obesus, fish caught from the tropical Atlantic Ocean (TAO), 1,313 from the west-central tropical Indian Ocean (WCTIO) and 391 from the Eastern and Central Tropical Pacific Ocean (ECTPO) estimated L50 of female bigeye tuna in the TAO, the WCTIO and the ECTPO were 117.7 cm, 119.3 cm and 117.5 cm respectively, for male bigeye tuna, the estimated L50 in the TAO (119.5 cm) was larger than that in the 48
WCTIO (117.7 cm). The Akaike’s information criterion showed that the Lysack’s (1980) model can be accepted as the best model for estimating L50 of bigeye tuna.
Pauly (2010) recorded the length for maturity of snapper species are recorded are as follows: Lutjanus analis, (510 mm); Lutjanus synagris (236 mm); Lutjanus vivanus (518 mm) and Growth values (Lmax) for Lutjanus analis (850 mm), Lutjanus synagris (650 mm), and Lutjanus vivanus (750 mm) in NE Brazil. Currey (2010) studied the resilience of reef fish species on the Great Barrier Reef and in Torres Strait Sex and maturity on the basis of macroscopically (Lutjanidae) and histological studies (Lethrinidae and Serranidae) and the proportions of females (and mature females) in each age class data was calculated for each species for the sex- changing species the proportions of females were derived from the fit to the logistic equation: Ps = 1 – (1 + e -ln19(S – S50)/(S95 – S50))-1;where Ps is the proportion of females (relative to males) in age s, and s50 and s95 are the lengths and ages at which 50% and 95% of the population are males for each species, respectively. Operational sex ratios were also calculated for each species as the ratio of mature females to mature males. Departure from a 1:1 sex ratio was tested using a chi-squared test using Yates correction for continuity.
Fry et al. (2009) discussed the reproductive biology and sexual maturity of Lutjanus sp in Eastern Indonesia and described the L. malabaricus had a less defined pattern with two peaks of reproductive seasons January–March and October and the size at first maturity observed at 240 mm for males and 250–300 mm for females as well as the L50% estimates were similar between species in northern Australia: 270–280 mm (males) and 350–370 mm (females).
Fontoura et al. (2009) discussed the reproduction and spawning of fishes and stated that the correct estimates of size at first maturity (L50 - length at which 50% of the fish are mature) are useful for fish stock management and proposed different methods to estimate the L50 %.
Hay et al. (2005) discussed reproductive biology of Lutjanus johnii and reported the Preliminary indications the Lutjanus johnii are that 50% of females are mature at 63 cm and 50% of males are mature at 47cm.
49
Van Doorent et al. (2005) discussed the analysis of size at maturity by using maturation rate models Evolution, the maturation decision on the basis of a maturation process by individual, that the maturation can depend on the concentration of a specific hormone that decays after birth, the maturation rate then is determined by the rate of change of the hormone concentration, and the maturation probability can be obtained by integrating the concentration changes over ages, another type of process occurs when the organism only changes maturation status when it grows.
Kamukuru and Mgaya (2004) provides the information in comperession of size at first sexual maturity (LM50), sex ratio, fecundity, and breeding season of L. fulviflamma in least fished Mafia Island Marine Park (MIMP) and intensively fished areas (IFA) between May 1999 and April 2001. On the effects of exploitation on reproductive characteristics of blackspot snapper, Lutjanus fulviflamma (Forsskål 1775) in Tanzanian coastal waters.
Andrade (2003) observed and studied the compression of life history and ecological aspects of Lutjanids and reported that the mostly relative to snappers having supper family Lutjanidae and growth is a particularly significant as a fecundity an increasing body functions/size and snappers are fast growing fish with high rate of maturity based on 103 species in sub family, snappers are diocious and gonochoristic, having separate sex throughout the life span, breed in full moon season and migration is relative to spawning in several species of Lutjanids, generally female spawn in several times.
Chakroun-Marzouk and Ktari (2003) studied the size at first maturity and on the seasonality in reproductive activity are very close to corresponding data for the Tunisian coast as obtained and determined first maturity lengths of 20 and 21 cm for both sexes (males and females).
IGFA (2001) Database reported the reproduction and spawning pettern of snapper in which they recorded the first maturity of Lutjanus johnii at 55cm (total length) of male specime.
50
According to the Roa et al. (1999) Size at 50% maturity (l50%) is commonly evaluated for wild populations as a point of biological reference to estimate L50%, a sample of organisms known to have just reached sexual maturity could be available and their arithmeticmean size can be used as an estimator during their study they estimated the size at sexual maturity: and resampling procedures where they reported the size at 50% maturity is commonly evaluated for wild populations, they evaluate three procedures to obtain a confidence interval for size at 50% maturity, and in general for P% maturity, 1). Fieller’s analytical method, 2) Nonparametric bootstrap 3). Monte Carlo algorithm. These methods were compared in estimating size at 50% maturity (L50%) by using simulated data from an age-structured population, with von Bertalanffy growth and constant natural mortality.
Manickchand et al. (1996) discussed the spawning pattern of Caribbean red snapper (Lutjanus purpureus) in Trinidad and determined the frequency of snapper in all maturity stages excluding immature for each 4-cm length class and the time of spawning was determined from monthly variations in the frequency of fish in each maturity stage size at maturity was 27 cm TL for males and 39 cm for females, spawning occurred year-round with peak activity from September to February.
Chen (1994) discussed the two-parameter logistic type model for estimating the length of fish and age at 50% maturity using the nonlinear least-squares method. The independent and dependent variables in the model are length (or age) and the corresponding arcsin-square-root transformed proportion of mature fish (Pi). The two parameters in the model are length (or age) at 50% maturity (L50 or A50) and instantaneous rate of maturation (K). A simulation study was conducted to examine the statistical behaviour of the proposed model in estimating L50 and K. The L50 was well estimated with a small bias (<1%) using the proposed model in all simulation cases. The K was well estimated (bias < 1%) when its true value and the variance in
Pi were small. The proposed model was found to have relatively smaller bias than the probit and Lysack's methods in estimating L50 (or A50). To examine whether there are significant differences in maturation patterns between different groups of fish, we propose fitting the maturation data to the proposed model, and then conducting an
51 analysis of residuals sum of squares to test whether there are significant differences in the fitted models.
Davis and West (1993) discussed the reproductive biology of Lutjanus vitta and mature specimens of smallest length group were studied, which had ripe stage ovaries from August to December, included for estimating size at first maturity analysis. The smallest specimen having hydrated oocyte (ripe) was 13.5 cm TL, which occurred during October 2003 and November 2007-08.
Hunter et al. (1986) studied the size-at-maturity of snappers and considered as the smallest length at which 50% of the fish in the sample had yolked or ripe stage ovaries.
Allen (1985) described the lutjanids are Gonochoristic (sexes separate), reaching sexual maturity at about 40 to 50% of maximum length, with big females producing large numbers of eggs,populations in continental waters have extended spawning throughout the summer, occurring around islands spawn throughout the year with peaks in spring and fall; lutjanids are batch spawners, with individual females usually spawning several times in a reproductive season, spawning isapparently at night, on some occasions coinciding with spring tides and Lutjanus lutjanus (Big eye snapper) reach at maturity at 12 cm TL. Thompson and Munro (1983) discussed the reproduction status of Lutjanids as females and males were mature between 500mm and 555mm and 550mm and 600mm, respectively, the length-at-maturity for females and males was much lower.
Grimes and Huntsman (1980) and Arnold et al. (1978) studied the reproduction of Gray snapper and indicators of the temporal distribution of spawning (i.e. juvenile otoliths, oocyte diameter, they aggregate on offshore reefs to spawn and are probably histological stage of gonads) indicated peaks in spawning from May until August and a dominant peak in mid-July.The spawning time has been related to both increasing water temperature and photoperiod for other lutjanids.
2.3.4 Spawning seasons
52
According to the India biodiversity portal (2013) spawning season and big eye snapper (Lutjanus lutjanus) spawn in March and November at Gulf of Aden and from January to June in the gulf of Suez, the spawning season of L. fulviflamma in Kenya marine water show prolonged spawning season from October to March.
Ken (2013) reported the spawning in Lutjanids as during March and November in the Gulf of Aden and off East Africa respectively, and from January to June in the Gulf of Suez and Lutjanus johnii perform dioecism type of reproduction with external fertilization in nonguarders open water/substratum with scatterers egg scatterers in Andamman Sea.
Matheus et al. (2011) provided the information about spawning season of commercially important snappers and groupers available from north and central West Atlantic during the study they observed gonads were collected during 2005 to 2007 and studied the spamming period with the help of (GSI) Gonadosmatic index as well as macro scope analysis.
Nanami et al. (2010) observed main spawning season was observed between June and October, estimated the reproduction of lutjanid species, Lutjanus decussatus (checkered snapper) around Ishigaki Island, high gonadosomatic index values were found around the time of the last quarter moon for each month from June to September.
Burton et al. (2005) reported the snapper’s ar a solitary species, and rarely seen in groups outside of the spawning season, spawns throughout their range, the spawning aggregations occur from April to September, at outer reef slopes, and on reef promontories and drop-offs, the snapper is oviparous, releasing pelagic eggs that move freely with the water currents, as is typical of pelagic spawners, the number of eggs is dependent upon the size of the female, with larger fish containing more eggs, after spawning, the adult fish moves offshore to deeper waters the Lutjanus analis spawns offshore in groups in which spawning typically occurs in summer.
53
Hay et al. (2005) investigated the stage of gonads of female and male Lutjanus johnii indicate that this species under goes a prolonged spawning period from early September to late April.
Paris et al. (2005) recorded spawning season of Mutton snapper from February to September in the Caribbean spawning months vary with location, also vary annually depending on when full moon falls in the month such as the peak spawning period was May and June in Cuba reported.
Knuckey et al. (2005) observed spawning period at southern queen having prolonged from September to April and further investigated the biology and population of Golden snappers (Lutjanus sp) 80 % female mature at 62 and male at 46 cm.
Shimose and Tachihara (2005) observed reproductive biolgy and estimated spawning season from April to July, peaked in May and June, with a faster growth rate up to 2 years will allow reproduction at a young age and provide many chances for spawning throughout their long life.
Leu et al. (2003) observed spawning of mangrove red snapper (Lutjanus argentimaculatus) naturally in captivity without use of hormonal treatment and discussed the growth rate.
Chakroun- Marzouk and Ktari (2003) spawning was also reported for the period July and August, and sexual resting extended from September to March.
Aguirre-Leon et al. (1996) reported seasonal patterns of Lutjanus species were collected from Cozumel reefs during 1988-1991,dominant fishes were observed with the help of weight measurement and distribution in system, described that the some Lutjanids reproduce on barrier reefs and juvenile were found at 1.0 m to 1.7 meter at sea grass bed of shallow waters.
Ralston et al. (1988) investigated the spawning period and distribution of larvae of Lutjanids in Great Bear Reef (GBR) specimens collected as ichthyoplankton in the
54 central GBR every two weeks from late January to late March and found maximum concentrations of lutjanid larvae in late Febraury and mid-March collections where the light-trap collections of pelagic juveniles show a similar distribution, with good catches recorded in Nov/Dec- Jan.
Leis (1986) Observed spwing season of Lutjanids in Great Berear Reef (GBR) and the Lutjanids larvae observed in shallow waters in the immediate vicinity of reefs of the GBR lagoon, lurjanid larvae were present year-round but were most abundant in spring and summer.
Bradley and Bryan (1975) studied the reproduction in Lutjanids and investigated the the long spawning seasons and constant requirements in a population as reason for difficulty to assigning red snapper observed through age from length frequency data. 2.3.5 Fecundity
Cappo et al. (2013) reported fecundity of fish from the equator might be expected to have much larger ovaries (and hence batch fecundity) and a longer spawning life in comparison with their smaller counterparts close to the equator. Longenecker et al. (2012) investigated the fecundity of Lutjanus biguttatus (Perciformes: Lutjanidae) and described Oocytes stages of teleost fishes as Wallace and Sellman. (1981):-
I. (Primary Growth) Ellipsoid to circular shape. Prominent (> 30% cell diameter), circular nucleus with well-defined borders; possibly containing small nucleoli. Cytoplasm stains darkly and uniformly. Zona radiata absent. 20-80 μm (50 μm).
II. (Cortical Vesicle) Larger (2 – 4x) and more circular than stage I. Boundary between nucleus and ooplasm indistinct. Cytoplasm stains darkly and contains many non-staining (white) lipid vesicles. Mid to late stages with conspicuous, lightly staining, acellular protein “shell” (zona radiata). 120-250 μm (170 μm).
III. (Vitellogenesis) Large (usually 2x stage II) and circular. Nucleus usually visible only during early stage III. Cytoplasm a mixture of oil droplets (non-staining) and
55 brightly-staining, round, uniform, vitellin (yolk protein) globules. Zona radiata prominent, stains brightly.180-570 μm (350 μm).
IVa. (Maturation) Larger but often less circular than stage III. Yolk protein coalescing into larger globules; eventually forming an irregular mass at oocyte center. Oil droplets (non-staining) also more-variably sized and coalescing. 350-700 μm (550 μm).
IV b. (Hydration) Almost 2x larger than stage III, very irregularly shaped. Cytoplasm a large mass of vitellin, usually staining lighter than previous stage. Oil droplets (non-staining) may be visible at periphery of vitellin mass or may have coalesced into a single, large droplet. Zona radiata conspicuously thinner and more irregular than in Stage III. 500-1100 μm (850 μm).
Kojis et al. (2011) observed during the Wild caught fish fecundity estimated values ranging from 500,425 eggs kg-1(2.19kg fish) to 496,345 eggs kg-1(2.82kg) and largest number of eggs kg-1 was 648,972 eggs in a 4.54kg.
Peterson et al. (2009) discussed the reproduction of red snapper and observed the batch fecundity calculated for females with hydrated oocytes and significant, positive relationship between TL and batch fecundity for females (BF = 9,548TL – 5,224,104; r2 = 0.67, p = 0.002)were observed, ranged from 560 – 937 mm TL and all batch fecundity values were low regardless of fish size, and average size female” of 2,900 g would be capable of spawning 669,750 eggs during each spawning event for a total of 46,578,068 eggs over the 6-month reproductive season (June – October).
Fitzhugh et al. (2009) observed the batch fecundity and an attempt to estimate spawning frequency of king mackerel (Scomberomorus cavalla) in US waters.Gametogenesis was monitored histologically in wild-caught red snapper (Lutjanus campechanus, Poey) maintained in captivity under simulated natural photothermal conditions. Gonads were collected every 2–3 weeks (average n = 14) for histology during the pre-spawning season (February to May, temperature increasing from 16°C to 24°C). Primary vitellogenic oocytes were first observed in one female when temperature reached 20°C. Subsequent samples revealed females in pre- 56 vitellogenesis or at early stages of vitellogenesis, although one female had tertiary vitellogenic (Vtg3) oocytes. Ovarian biopsies taken during the late spawning season (16 July) revealed that four of eight sampled females had Vtg3 oocytes.
Accioly et al. (2008) discussed cytogenetic studies in Brazilian fishes (Perciformes) with the help of chromosomal analysis in members of families Sciaenidae (croakers and drums) species, Menticirrhus americanus, Ophioscion punctatissimus and Pareques acuminatus and Sparidae were, Archosargus probatocephalus from Brazil, by using of tow techniques 1-conventional staining (Giemsa) Ag-nucleolar organizer regions (NORs) ,2-C-banding techniques. The diploid values of chromosome were calculated and found equivalent to large heterochromatic blocks, in M. americanus (1st pair), O. punctatissimus (10th pair), P. acuminatus (2nd pair), and A. probatocephalus (3rd pair). Heterochromatin was detected at the centrometric position in most chromosome pairs.
Evan et al. (2008) investigated the batch fecundity in Lutjanus carponotatus, increased with fork length in a non-linear relationship that was best described by a power function .i.e. differed by more than 100-fold among individuals, with a range from 7,074 to 748,957 eggs in fish ranging from 184 to 305 mm fork length. Furthermore, egg diameter increased with fish size and investigated relationships between body size and fecundity of a reef fish species and examines the potential benefits of increased batch fecundity in no-take reserves compared to fished areas around the Palm, Whitsunday and Keppel Island Groups, Great Barrier Reef, Australia. Liu et al. (2007) discussed the Genetic diversity and molecular markers of five snapper species in order to protect and develop valuable snappers (Lutjanus spp.), genetic diversity and molecular markers of five species (Lutjanus vitta, Lutjanus fulvus, Lutjanus fulviflamma, Lutjanus sebae and Lutjanus stellatus) analysed using random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) techniques, indicating comparatively rich genetic diversity among these fish.
Kamaleie (2007) studied the reproductive biology and distribution of Golden snapper (L.johnii) in which reproductive factors such as Lm50, spawning season, fecundity
57 and sex ratio and spawning season was determined based on GSI, the lenght of females were matured (L50) 44cm and the fecundity range was calculated in each month. Maximum fecundity was 2539592 in the month of July.
Bourque and Phelps (2007) studied the reproductive biology and estimated the fecundity of red snapper, Lutjanus campechanus, captured from wild and induced through ovulate by human chorionic gonadotropin (hCG) injection Eggs were evaluated by egg quality parameters: buoyancy, fertilization, egg size, and oil globule size and number, the average fecundity was 343,377 ± 30,805 eggs/kg, with a mean percent fertilization of 79.0 ± 1.74%. and observed the mean percentage of floating eggs per spawn was 91.8 ± 1.75% with mean egg diameter for floating eggs was 778.3 ± 2.09 μm.
Emata (2003) used a reliable breeding technique for mangrove red snapper, Lutjanus argentimaculatus (Forsskal 1775), and observed high fecundity by using standardized indices of female maturity (based on mean oocyte diameter of ≥0.40 mm), time of injection (1000–1130) and sex ratio (one female to two males), range per spawn recorded from 0.05 to 6.35 million, exhibited lunar periodicity mostly occurring 3 days before or after the last quarter and new moon phases and occurred consistently.
Pauly et al. (2002) discussed batch and annual fecundities of Lutjanids i.e. highly variable with female size such as a single ripe female red snapper (L. campechanus) of 610 mm TL yields over 200 times more eggs than a 420 mm TL individual.
Kamaleie (2001) studied the reproductive biology of golden snapper (L. johnii) in Hormozgan waters and determine the reproductive factors fecundity Lm50, spawning season, sex ratio and spawning season on the basis of GSI from April to July with a peek in August, Maximum fecundity was observed 2539592 in July. Chi square test was applied to compare female and male frequency, and did not show a significant difference (p=0.012) yearly.
Watanabe (2001) investigated fecundity values of mutton snapper range from 186,500 to 603,00 eggs kg-1for fish 2.3-2.27kg and observed one egg size group
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(mean egg diameter = 0.382 mm, range = 225-475 mmFL) in an ovarian biopsy of a 3yr old hatchery reared female of mutton snapper (460mm FL).
Collins et al. (1996) provided information regarding spawning and fecundity of Lutjanus campechanus,(an intermediate spawned) with the help of batch fecundity/ spawning frequency methods and the annual fecundity of Lutjanid species ranges from 0.012 to 59,666 million eggs per female by assuming an equal spawning frequency for all sizes and ages. Based on larval abundance, two types of seasonal reproductive patterns are common to the family Lutjanidea.
Leis (1987) discussed the fecundity and reproductive biology of lutjanids that the Lutjanids are higher fecund, with the large female produceing 5-7 x 1,000,000 ova with a diameter ranging from 0.65 to 1.02 mm , usually contain a single oil droplet 0.12 – 0.20 mm in diameter (except in L. erythropterus, where no oil droplet is present ) which provides buoyancy. Eggs are similar to most pelagic eggs, which makes them difficult to identify from plankton samples. Eggs hatch after 17 to 36 hours, depending on the species and temperature, and the just- hatched larvae are also similar to the vast majority of larvae coming from pelagic eggs.
Roff (1983) recorded the (John’s snapper) L. johnii has a relatively gradual growth trajectory through early life, maturing at 6–10 years and at 70–80% of L∞, and reaching an asymptotic length at ~18–20 years. The consistent, sex-specific differences in growth rates are consistent with functional gonochorism, higher selective pressure for females to grow to a larger size and have a higher fecundity.
Balan (1971) discussed fecundity of fish and expressed by equation F=a & b∟ in which F= fecundity in thousand L=length (cm) a and b constant base on Naperian logarithm, Radhakrishna and Nair (1991) discussed Age and growth rate of Rainbow Sardine Dussumiaria acuta from Mandapan area.
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2.4 Fishery Information Initiative discussed in Encylopedia of Britannica (2013) and reported that the 105 species of fishes of the family Lutjanidae (order Perciformes), found, often in abundance, throughout the tropics, these are active, schooling fishes with elongated bodies, large mouths, sharp canine teeth, and blunt or forked tails, snappers are usually rather large, many attaining a length of 60–90 centimetres (2–3 feet), carnivores and prey on crustaceans and other fishes, snappers are valuable and well- regarded food fishes. The emperor snapper (Lutjanus sebae), a red and white Indo- Pacific fish; the gray, or mangrove, snapper (Lutjanus griseus), are well known species of the area, the yellowtail snapper (Ocyurus chrysurus), a swift-moving Atlantic species with a broad, yellow stripe from the nose to the wholly yellow tail; and the red snapper (Lutjanus campechanus), a bright-red fish (one of several red- coloured snappers) famed as food and found in rather deep Atlantic waters. Ruppert et al. (2013) reported the Lutjanus are most important fishes of Pacific island, contains about 60 species, Lutjanids feed on smaller fish, crabs, shrimps, and sea snails, eaten by a number of larger fish. In some locations, species such as the two-spot red snapper, Lutjanus bohar, are responsible for ciguatera fish poisoning. Snappers have separate sexes. The smaller species have a maximum lifespan of about 4 years and larger species live for more than 15 years, many common species grow to sizes of 25 to 35 cm and reach reproductive maturity at about 45% of their maximum size (that is, 11 to 16 cm in the most common species), generally spawn throughout the year in warmer waters but during the warmer months in cooler waters. Some travel long distances to particular areas along outer reefs and channels to breed (in spawning aggregations), often around the time of the new moon and full moon. During breeding, females (release eggs (often more than 1 million) and these are fertilised by sperm released by males (In most reef-associated snappers, fertilised eggs hatch within a day or two into small forms (larval stages) that drift with currents for about 1 month. Less than one in every thousand of these small floating forms survives to settle on a reef as a young fish (juvenile). And less than one in every hundred juveniles survives the period of 3 to 8 years that it takes to become a mature adult capable of reproducing. Minimum size limits for snappers have been applied in some countries (e.g., 30 cm length from the tip of the mouth to the middle of the tail). Size limits should be applied to individual species.
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Sheridan (2008) discussed weight of fish, biology of fish and Gonadal maturation in relation to spawning season and diet composition of nine species of Lutjanus for tropic level, examined nine common species in spring, summer, and fall food system found in off shore habitat and observed (Centropristis ocyurus), (Prionotus tribulus) primarily consumers of crabs, (Ancylopsetta ommata) consumer of fishe, crabs, and stomatopod. (Diplectrum bivittatum), (Prionotus rubio), (Centropristis philadelphica), (Menticirrhus americanus), and (Lutjanus campechanus) feed on shrimps, mostly fishes diets varied with aspect to size (age), time, area, depth, and season also studied fish length-weight relationships and gonadal development in which Ripe gonads were found frequently during summer in dwarf sand perch, during fall in oscillated flounder and bighead sea robin, and during spring for other species, except no ripe red snapper or bank sea bass were collected. Rock sea bass was found to be a protogynous hermaphrodite, while dwarf sand perch is asynchronous hermaphrodite.
David et al. (2008) investigated status of red snapper (Lutjanus campechanus) and highlighted possible impacts of shrimp trawling on age-0 fish life history parameters on the northern Gulf of Mexico (GOM) continental shelf.
Katsuhiro et al. (2003) studied the habitat and distribution of juvenile and young John's snapper Lutjanus johnii, Matang mangrove estuary, west coast of Peninsular Malaysia.
2.4.1 Total length and body weight relationship
Kasapoglu and Duzgunes (2014) investigated the length-weight relationships of marine species of Lutjanus caught by five gears from the Black Sea and during the study observed the thelength weight relationship (LWR) equation of 25 species along the Black Sea coasts of Turkey was evaluated based on the first comprehensive survey.
Dailiri et al. (2012) discussed the Length weight (LW) and Length Girth Relationship (LGR) of Lutjanus argentimaculatus, Lethrinus nebulous Argyrops spinifer and C.
61 talamparoides four commercial fishes of Northern Persian Gulf, during two years collection in which body girth calculated by three procedures ,vertical diameter known as G1, behind gill cover G2 and in front of first dorsal fin G3 and total length, to calculate the swimming capability of fish and role in food web during 2006 to 2008 is use full for gill nets fisheries.
Mansor et al. (2012) discussed the importance of length weight relationship of Lutjanus Lutjanus johnii, Lutjanus russelli to estimate the biomass of fishes in a habitat and stock assessment and K factor, in fisheries sciences (Weatherly and Gill, 1987). This factor is the quantitative parameter that represents the well-being of the fish.
Masood (2009) studied the comparative status of length weight relationship of Lutjanus sp (L .russellii, L. johnii, L. fulvus, L. malabrius, L. lutjanus and found L. lutjanus, L. johnii and L. fulvus) through scale from Pakistan from main landing center the Karachi Fish Harbour.
Naeem et al. (2010) discussed the length- weight and condition factor relationship of farmed hybrid (Catla catla ♂X Labeo rohita ♀ ) from Multan Pakistan Hybrid (Catla catla ♂ x Labeo rohita ♀ ) of variable sizes ranging from 4.4 – 27.0 cm total length and 0.52 –258.35 gm body weight.
Masood and Farooq (2010) observed length weight relationship and conditions factor parameters of fire species of Lutjanus discussed the correlation b/w length and weight of fish and define that the Lutjanus species exhibited both positive and negative pattern of growth.
Adeyemi (2009) observed age growth and maturity of commercially important Lutjanus sp collected from local landing centers and five age groups studied with the help of different methods by scale and opercula bones as well as length weight relationship of fishes Isotropic growth was seen.
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Jawad (2009) investigates the relationship of Lutjanus banglaensis between opercular
(Gope) and maximum girths (Gmax) to total length (Lt) for 10 fish species captured from Shatt al-Arab River, Basrah, studied mass asymmetry in fish otolith,calculated the difference between right and left otolith (Sagitta) and result calculated about otolith mass asymmetry has shown the value not depended on fish size.
Samat (2008) observed length-weight relationship of fish at river Malaysia peninsula and stated that the relationship having great importance in research for fisheries sector and changes in length and growth tells the year class and collected data can be use for study of mortality rate also fishing were identified during study estimated the age with the help of non Bertalanffy Growth (VBGF).
Gaygusuz (2006) defined conversion of Total length, Fork and standard Length of 40 fish species from Turkish waters observed the relationship by using of Morphological Physiological behavior and biochemical, significance of regression assessed by analysis of Variance (ANOVA) that’s significant for differences in slop of length and factors may be effected on proportion of total, fork and standard length as well as quality and availability of food.
Walter (2006) provide the details for snappers Golden Snapper (Lutjanus johnii) and Red Snapper (L. malabaricus and L. erythropterus) sexual maturity at around 97 cm in total length (TL) of stripey snapper at three years of age observed and golden snapper are a long-lived and late-maturing fish, fifty per cent of females reach sexual maturity at 63 cm TL (eight to ten years old) and males with 50% maturing at 47 cm TL.
Ramachandran (2000) studied the length-weight relationship of Lutjanus vitta were studied based on samples collected from 30 and 80 m depths along the southwest coast of India during October 1999 - December 2009.
Russell (2000) discussed the length weight relationship of Lutjanus sp and described one measure of the condition of a fish is its relative weight, relative weight is the ratio
63 of the actual weight of a fish to what a rapidly growing healthy fish of the same length should weigh, called standard weight. Fish with high relative weights are fat while those with low relative weights are thin.
Edward (1994) described length and growth relationship and age of Hawaiian Pink Snapper (Pristipomoides filamentosus) in reference of work done previously by Haight et al. (1993) in which they determined relationship between age and growth of sub adult and adult fish.
Weatherley and Gill (1987) study of weight-length relationship its applied value in fish biology; these studies are also widely used for conversion of the growth-inlength equation to growth-in-weight for use in stock assessment models and estimation of biomass from length observations.
Mason (1985) defined length weight relationship of lutjanus sp through otolith shiftless and fish weight and length in relation of age and growth.
Zar (1984) discussed the length weight relationship through parabolic equation (W =aLb) was then transformed into a linear equation using a logarithmic method: Ln W = Ln a + b Ln L based on the equation, the estimated values of a and b were obtained using least-squares regression the determination coefficient (r2) was used as an indicator of the quality of the linear regression, t-test analysis was carried out for the length and weight data of each species to confirm the significance of the relationship at P < 0.001.
Le Cren (1951) discussed the length-weight relationship (LWR) of fish and stated that this relationship is an important factor in the biological study of fishes and their stock assessments, is particularly important in parameterizing yield equations and in estimations of stock size and helpful for estimating the weight of a fish of a given length The length–weight relationship (LWR) was estimated by using the equation W = aLb where W = weight in grams, L = total length in centimeters, a is a scaling constant and b the allometric growth parameter. Alogarithmic transformation was used to make the relationship linear: log W = log a + log b L for each species a
64 regression was used to estimate the intercept (Log a) and the regression coefficient or slope (b).
2.4.2 Catch per Unit effect
Walter et al. (2012) reported provide details the resident recreational fishers captured a diverse range of most common scale fish harvested were snappers (23% of the total harvest) within the snapper group, Golden Snapper (Lutjanus johnii) and Red Snapper (L. malabaricus and L. erythropterus) accounted for the largest portion of the harvest, estimated at 80 000 and 37 000, respectively. Cod (~27 000), Grass Emperor (~23 000), Stripey Snapper (~21 000) and Black Jewfish (~11 000) were also significant components of the harvest.Black Jewfish have a fast growth rate.
Karnaukas and Babcock (2012) discussed the comparisons between abundance estimates and Catch Per Unit Effort in a Patch Reef System and reported that the most important fishes were yellowtail snapper Ocyurus chrysurus, saucereye porgy Calamus calamus, lane snapper Lutjanus synagris, white grunt Haemulon plumieri, and mutton snapper Lutjanus analis, the average length of captured fishes was greater than the average length observed in the UVC, differences in length between individuals observed in UVC and those caught in the CPUE were significant for these top five species (p < 0.001 for all species except L. analis, p = 0.02). When catch per unit effect (CPUE) and UVC were collected simultaneously on the same patch (30 sites) the MANOVA found that species composition in terms of abundance of the top five species was significantly correlated between CPUE and UVC samples (p = 0.02, R2 = 0.29). However community structure in terms of biomass was not significantly correlated (p = 0.19). For the same set of sites, when CPUE and UVC were collected at different times, neither abundance (p = 0.27) nor biomass (p = 0.53) estimates were correlated.
Newman et al. (2008) investigated the Northern demersal scalefish status to manage the fishery statutory (compulsory) monthly catch and effort summaries are compiled by fishers and reported in the catch and effort statistics (CAES). The fishers report catch (kg) by species or species group. They also discussed they status of L.johnii in 65 the catch location reported by 1 degree blocks by a vessel monitoring system (VMS) has been operating since 1998 and provides data about vessel location during each trip they further reported that the fishing in Northern demersal scale fish occurs throughout the year. However, fishing activities may be interrupted from December to April, as cyclones are more common during this period.
Rudershausen et al. (2008) observed the comparison of Reef Fish Catch per Unit Effort and Total Mortality of red porgy and vermilion snapper between the 1970s and 2005–2006 in Onslow Bay, North Carolina in which they the positive bias in CPUE for 2005– 2006, found declines in red porgy and vermilion snapper at Snowy Edge.
Saul et al (2005) standardized catch rates for yellowtail snapper captured by traps indicates a similar trend to the nominal catch per unit effect (CPUE) calculated for traps with a decline to a low point in 1994 followed by an increase. 95% upper and lower confidence intervals during the study year and season were both found to be significant, but the interaction was only significant for the analysis of positive trips resulting the final index was estimated with this interaction as a random factor using the glimmix program.
Skalski et al. (2005) reported the catch per unit effort (CPUE) is an indirect measure of abundance of a target species in fisheries and conservation biology ,the changes in catch per unit effort are inferred to signify changes to the target species' true abundance, decreasing CPUE indicates overexploitation, while an unchanging CPUE indicates sustainable harvesting. CPUE has a number of advantages over other methods of measuring abundance. It does not interfere with routine harvesting operations, and data area easily collected. The data are also easy to analyse, even for non-specialists, in contrast to methods based on transects, means that decisions about stock management can also be made by the people doing the harvesting, the best practice is to standardise the effort employed (e.g. number of traps or duration of searching), which controls for the reduction in catch size that often results from subsequent efforts. Although Catch per unit effect (CPUE) is a relative measure of abundance, it can be used to estimate absolute abundances.
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Russell et al. (1999) observed the catch-per-unit effort of juvenile of Mangrove Jack, (Lutjanus argentimaculatus) in the wet tropics streams the fish less than 100 mm LCF and the abundance (catch per unit effort) of mangrove jack in rivers decreased with increasing distance from the river mouth. Gulland (1983) investigated the rate of catch or catch per unit effort (CPUE) can be considered as an index of stock abundance in the waters.
Ralston and Polovina (1982) examined catch and effort statistics for the deep-water line fishery in the Hawaiian Islands during the period 1959-1978, they examined statistics for 13 species from4 banks and attempted to fit Schaefer surplus-production models to the data. catches were maintained at high levels but catch per unit effort declined with increasing effort.
2.4.3 Sex Ratio
Cezar et al. (2012) studied the reproductive aspects and sex ratio of the Brazilian snapper Lutjanus alexandrei, including a description of the development of oocytes and spermatogenic cells, sex ratio of male and female was 1.6 males: 1.0 female were females(39.4%) and 327 (60.6%) were males with these latter. Males were more abundant in the total sample (χ2 = 24.0666, p < 0.05, df = 11), which produced a male biased sex ratio (1.6 males: 1.0 females). Males were more abundant in February (χ2 = 5.4615, p < 0.05, df = 1) and August (χ2 = 6.4606, p < 0.05, df = 1).
Kritzer (2012) studied the reproductive biology of lutjanids and described the some species of lutjanids occur in a 1:1 ratio independent of size , whereas the sex ratio of other species varies predictably with size Overall, sex ratio in this L. biguttatus population, from the size class at male maturity (12 cm) through maximum observed size (19.8 cm), is 1:1.2 ♂:♀. However, a χ2 analysis indicates the observed ratio among these 22 individuals is not significantly different from 1:1 (χ 2 = 0.1818, df = 1, P = 0.6698) further, sex ratio does not appear to predictably vary with size. The latter analysis is based on a small number of individuals, with no more than 5 individuals present in any one size class. However, when present, size-specific sex ratios are striking; we have detected variable ratios with similarly small-sized samples
67 in small-bodied Hawaiian fishes (Longenecker and Langston 2008, and unpublished data).
Kojis et al. (2011) discussed the reproductive biology and sex ratio (male and female) of mutton snapper and in catches from Gladden Spit i.e. nearly equal (1:1.2), where in St. Croix males caught in the MSSCA were more than twice as abundant as females (2.3:1). They observed the absolute numbers of male and female fish of larger sizes >525mm, similar on St. Croix (20 males to 22 females, sex ratio = 1:1.1) females mature at a larger size than males.
Heupel et al. (2009) studied the size and age by sex and sex ratios Lutjanus johnii and gonadosomatic index (GSI = gonad weight / W × 100) was calculated for each sample, providing a relative measure of reproductive stage and reproductive stage of each individual was assessed by macrosexing or histological analysis.
Russel (2008) sex ratios can have profound impacts when predicting population-level reproductive output. Sex-ratio patterns are variable within the lutjanids. Kritzer (2004) studied Biology ,sex specific growth, and female maturation of the stripy bass (Lutjanus carponotatus) to estimated sex ratio and sex specification schedule, age and size specification schedule of female maturation, spawning season spawning output with the relation of body size and weight at Lizerd Island at Northern from Great barrier reef.
2.5 Age and growth studies
Cappo et al. (2013) estimated the age and growth of Lutjanus johnii through sectioned otoliths of John’s Snapper (Lutjanus johnii) from 4 regions of northern Australia, recorded size and growth rates of and the populations of John’s Snapper from the equator had the largest body sizes, in line with James’s rule, as maximum age of 28.6 years, nearly 3 times previous estimates, was recorded and the largest individual was 990 mm in fork length.
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Hussain and Khatoon (2010) observed the growth of lutjanus Johnii in cages and observed the growth of fish in floated cages in to culture and monoculture related in fish gave better results and grow up to 27gm.
Fry and Milton (2009) examined the age and growth and life histories of Lutjanus erythropterus and Lutjanus malabaricus from northern Australian and eastern Indonesian through otolith, the formation of opaque growth increments in otoliths began during April to September for northern Australian fishes and September to April for eastern Indonesian fishes, age (max) observed were 42 and 48 years for Lutjanus erythropterus and Lutjanus malabaricus, the Eastern Indonesian red snappers grew faster than northern Australian fish and growth was observed as similar for northern Australian Lutjanus erythropterus populations. Beyer (2008) determined the age of red snapper, Lutjanus campechanus through shape analysis and validation of otolith annular increments, examined growth of otolith through mask and recapture study with known age hatchery in northern gulf of Mexico with the help of age validation methods and discussed timing of otolith growth rings in red snapper was examined through a mark-and-recapture study and with known-age, hatchery-reared fish and discussed the annual periodicity of growth ring formation was shown in both adult and young red snapper. Mendoza (2006) observed age and growth of L. purpureus and provides an overview of the traditional and applications of the otoliths with a short description of the traditional methods for age determination, the opaque zones in the otoliths were observed, formed during the period of greatest growth and the hyaline zone is laid down usually during the period of slowest growthand in many species of the outer rings become very narrow once the growth rate of slows down, narrow rings sometimes grow only on the underside of the otolith, can be seen through a cross section.
Rezende and Ferreira (2004) discussed the age, growth of dog snapper Lutjanus jocu in the northeast coast of Brazil through opaque marks, and marginal appearance in otoliths sections with counting along a transect running from the nucleus to the proximal margin parallel to sulcus acousticus edge, opaque bands in otolith sections towards the ventral or dorsal margins, multiples ring observed due to a more dispersed
69 deposition pattern and the the best region for reading located towards the sulcus acousticus area.
Charles (2001) discussed age and growth of red snapper in Gulf of Mexico and monitor year class.
Marriott et al. (2000) used five common methods of determination of age and growth for Lutjanus johnii (Lutjanidae) with the help of annuli visible on scales, whole otoliths, sectioned otoliths, whole vertebrae and sectioned vertebrae of Lutjanus johnii, in a sample of 44 younger fish up to 793 mm FL and 12+ years of age, where the most precise methods used whole otoliths, sectioned vertebrae and sectioned otoliths, linear comparisons from whole and sectioned otoliths, and sectioned otoliths and whole and sectioned vertebrae, for fish less than half the known longevity of the species. Finally they reported the sectioned otoliths provide the best method to determine the age of Lutjanus johnii.
Luckhurst et al. (2000) discussed the age and growth of Lane snapper Lutjanus synagris (Lutjanidae) at Bermuda through measurements of various dimensions of sagittae by use of image-analysis system (Optimas Imaging software) and validated formation of annulus by marginal increment analysis and distance from edge to last presumed annulus (D1) and distance between last and previous annulus (D2) in 2 yr old fish on a monthly basis.
Seshappa (1999) discussed four following methods for age determination of Indian fishes through scales, otolith and other hard parts, i) Peterson’s Method for length frequency analysis, ii) study of annular rings found at scales and other hard parts, iii) study of growth rings found on otolith and scales of fish under captivity, iv) by tagging analysis, they used Peterson’s Method for length frequency data , age and growth ratio of fish and evaluated Morphometric, growth and other biological characters of red snapper by using a composite of length and other measurements of red snapper from Gulf of Mexico to combined the data from prior analyses with more recent observations and studied age and growth of Indian fishes with the .help of rings found on otolith, scales and other hard parts.
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Patterson et al. (1998) investigated age and growth of red snapper and studied the discriminating between age-0 red snapper, Lutjanus campechanus, nursery areas in the northern Gulf of Mexico using otolith microchemistry.
Manooch and Potts (1997) studied age and growth of red snapper, Lutjanus campechanus, Lutjanidae along the southeastern United States from North Carolina through the east coast of Florida.
. Hyndes et al. (1996) used the marginal increment (MI) analysis technique for determination of age and growth of Lutjanid through growth zones and described the marginal increment (MI) is the distance from outside to the outermost opaque zone.
Seshappa (1995) used growth rings present at scales, otolith and other hard parts of determination of age and growth of Lutjanus sp and provide the basic information regarding role of scales otolith and other hard parts in term of determination of age and growth
McPherson et al. (1992) estimated age and growth of Lutjanus sp of Great barrier leaf and calculated the age and growth parameter for stock assessment and manage the legal size of fish.
Hunt (1992) studied the age and growth of Lutjanids and reported the otolith size will increase with fish size within a family various species show significant differences in otolith morphology, therefore, it used to differentiate and characterize the species Whole and section otolith is used for age determination, reported that in small sized fish, since otolith is thin and clear so the number of growth zones is easy to count but in older fish whole otolith thick and opaque so section otolith is used to determined age.
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Campana (1990) discussed and validated the technique of the formation of rings in number of tropical and sub tropical species of Lutjanus and investigated the other methods of age determination are radioactive elements in the otoliths.
McPherson et al. (1988) discussed the determinations of age and growth of two Lutjanus spcies of Great Berear Reef (GBR) through whole otoliths the age of Lutjanus eryrhropterus and Lutjanus carponotatus,Lutjanus sebae and Lutjanus malabaricus in the Caims region determined and commented that the major difficulty in age detennination was the tendency of some otoliths to be completely opaque, showing no signs of check formation or translucent banding during the study they rejected as unreadable 22% of L. sebae otoliths and 13% of Lutjanus malabaricus otoliths, found otoliths more reliable for age determination scales or urohyals and, as for Lethrinus nebulosus.
Saila et al. (1998) estimated age through von Bertalanffy growth parameters from size-at-age data for estimation of age and growth of fish by use of nonlinear fitting techniques are recommended over the use of linearizing transformation.
Longhurst and Pauly (l987) and Williams (1994) used age determination techniques based on the examination of skeletal structures (otoliths, scales, other bones) of Lutjanids.
Kohn (1986) studied the age and growth of fish and suggested that if parameter values were estimated by formal optimization methods, it was essential to show that these estimates were reasonable and reliable for the biological data that the model was depicting.
Manooch (1984) determined the age and growth of Lane snapper with the help of rings found on sectioned otolith, oldest fish were observed at 10 years, they also calculated relationship between fork length to total length and other growth parameters were calculated with the help of Von Bertalanffy method.
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Beamish and McFarlane (1983) discussed the age and growth of Lutjanus and reported the accurate and reliable techniques are most important for the assessment age of fish earlier, scale was used for this estimation in teleost fishes but the data yields by scale were not reliable because scale showed irregularities in case of slow growing fish species and long aged species and now otolith of a fish are using by researchers for accurate age data for the determination of age and growth.
Chang (1982) reported the estimations of age and growth of fishes were evaluated with coefficient of variation, and average percent error for age determination defined by Beamish and Fournier (1981).
2.5.1 Based on fish otolith
Jawad (2012) used the otolith length and width of adult Lutjanus bengalensis to calculate the fluctuating asymmetry and estimation of growth in two characters and observed the level of asymmetry of the otolith width was the highest among the two asymmetry values obtained for the otolith of Lutjanus bengalensis, also described the lowest level of asymmetry in the two otolith characters is at the fish length ranging between 19.0-19.9 mm and the highest at the fish length ranging between 23.0-23.9 mm, and used otolith of lutjanus bengalensis for calculation of fluctuating asymmetry and studied relationship between the fluctuating asymmetry and condition in adult specimens collected from Oman near Muscat for provide the suitable habitat of Lutjanus bengalensis larvae and bilateral asymmetry in otolith mass of a fish is a abnormal activity of swimming.
Szedlmayer et al. (2012) discussed validation of annual growth rate of otolith in opaque and translucent areas in lutjanus camephanus, captured from wild and marked by tags injected oxytetracycline dehydrate (OTC), released in same habitat then recaptured after 2½ years, then dissected, collected otolith and studied the growth rings on an adult fish from August to December and normal timing zones formation observed in recaptured fishes.
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Bryan (2011) studied otolith growth histories of Lutjanus with the help of trace ring analysis technique from the animal growth increment gray snapper (lutjanus spp) in the northern Gulf of Mexico.
Jawad et al. (2011) discussed the relationship between fish length and otolith length and width in the lutjanid fish, Lutjanus bengalensis (Lutjanidae) collected from Muscat City coast on the Sea of Oman, otoliths used to identify fish species, to estimate their age and size regressions between otolith size (length and width) and fish length in Lutjanus bengalensis also observed and described the ANCOVA test which showed no difference in length and width of the right and left otolith of fish, and no significant difference was observed between regressions of length and width of otolith over fish size, and a single linear regression was plotted against total length (TL) for otolith length (OL) and otolith width (OW) they also reported that the morphometric relationships, and otolith length and width are good indicators of fish total length in the species studied.
Courtney (2011) discussed the age and growth of red snapper through otolith by counting opaque annuli (dark rings) along margin of sulcus as well as marginal edge.
Previero et al. (2011) determined the age and growth of the dog snapper (Lutjanus jocu), caught from Abrolhos Bank, Bahia State, and examine the formation of each ring was considered annual, by use of parameters of the von Bertalanffy growth function for dog snappers from Abrolhos Bank, estimated with the assumption of constant variance and constant CV, had marked differences.
Allen (2011) used of length, width and length of otolith of lutjanus benglensis for estimation of age and size of fish in Omani waters also discussed the age estimation.
Zorica et al. (2010) used otolith (Sagitta) of five pelagic fish species from Croatia and correlated with fish length and provided details relationship study of otolith morphology of five pelagic fishes and gives their finding that the otolith length are
74 using for estimation of age and growth rate of fishes and mostly is the biggest in deferent shapes in deferent fishes.
Aumend (2010) studied micro chemical analyses of otolith for age and growth and ontogenetic migrations of Lutjanus argentimaculatus from Great barriers reefs, in which they investigated the presence of trace element in inner juvenile core and outer region of otolith in adult specimens, most beneficial to identify the migration of Lutjanus species from nursery area to offshore water as adult grounds, during the research study they observed presence of trace elements in otolith of Mangrove jack particularly in coastal areas, examined micro chemical changes in growth of otolith of adult fishes they live in offshore waters for assessments of migration pattern of Lutjanus argentimaculatus and other species of Lutjanus.
Yamada (2010) studies the age and growth of mangrove snappers, Lutjanus argentemaculatus by use of fifth sections in coastal and reverie ones, for estimation of age they used 129 otoliths sections and analyzed monthly marginal growth index which indicated that the opaque zone formed once a year, the smaller fish moved from river to the coastal area to increase in size and fish of 1 to 3 years lived in coastal habitats, found that somatic and otolith growth was faster in 1 to 3 fish live in coastal habitat as compared to rivers habitat.
Ronan et al. (2009) investigated the reconstructing individual shape histories of fish otoliths and new image-based tool for otolith growth analysis and modeling Examined the growth of otolith through mask and recapture study with known age hatchery in northern gulf of Mexico with the help of age validation methods.
Anne (2006) discussed the demography of Pristipomoides multidens in northern Australia and a comparison within the Family Lutjanidae with respect to depth (2006) studied relationship between otolith weight and ageby use regression analysis with otolith weight as dependent variable and age as independent variable during the observation regression slopes were compared between sexes for each location use analysis of covariance (ANCOVA) and age-otolith weight relationship, predicted age
75 was estimated from otolith weight as acontinuous variable, transformed to a discrete variable by rounding to the nearest integer and age determined from sectioned otoliths.
Sérgio de Magalhães (2004) assessed the age and growth of Lutjanus jocu was through readings of growth marks in Sagitta otoliths, in the northeast portion of the Brazilian Exclusive Economic Zone during August 1996 to March 2000. Opaque bands, presumed to be annual, otoliths, showing ages from 0 to 20 and from 0 to 25 years respectively.
Allman et al.(2004) discussed age estimation and role of of red snapper (Lutjanus campechanus) otolith growth to estimate the fish size /age as well as opening time and annual temperature climatic signals they examined in otolith of adult and juvenile.
Pajuelo and Lorenzo (2003) reported the age and growth of lutjanids and marginal otolith increment increases when an opaque band forms and drops to zero when a new translucent band begins to form if increments are formed yearly, the mean marginal increment over time should show one modeand the peak should correspond to the time the yearly opaque ring formed, the size of the growth zone varies with time of sampling during the year and the age of the fish, because younger fish grow faster than older individuals, a larger marginal increment is expected, the quantitative marginal increment analyses should be standardized for age.
Newman (2000) investigated the age and growth through otoliths of L. erythropterus, L. malabaricus and L. sebae from the central Great Barrier Reef contained series of opaque and translucent increments deposited annually, age estimated up to 32 years for L. erythropterus, 20 years for L. malabaricus and 22 years for L. sebae were much higher, age estimates obtained from counts of increments on whole otoliths were consistently much lower and more imprecise, at all ages compared with counts from sectioned otoliths. The regression of sectioned age on otolith weight revealed consistent linear relationships among all three species were observed.
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Marriott and Cappo (2000) used five common methods of age determination of Lutjanus johnii were compared to determine their usefulness in monitoring the catch structure of a small Australian sportfishery, where presumed annuli were observed on scales, whole otoliths, sectioned otoliths, estimates the age with acceptable levels of precision after three replicate counts using all these methods with the exception of scale reading, the most precise methods was used by whole and sectioned otoliths, linear comparisons showed promise for calibration of results from whole and sectioned otoliths, and sectioned otoliths, comparison of the scale and otolith readings amongst experienced and inexperienced readers revealed systematic bias in the interpretation of the position of presumed annuli for fish less than 3+. It was concluded that sectioned otoliths provide the best method to determine the age of Lutjanus johnii.
Cappo et al. (2000) studied the validation of periodicity and timing of opaque zone formation in the otoliths of eleven species of Lutjanus from the central Great Barrier Reef the model was proposed for validation studies of the periodicity and timing of growth checks on otolith sections, based on measurements of otolith radii around tetracycline (OTC) marks and continuous variables were obtained by expressing measurements of the marginal increment and distance between the OTC mark and the subsequent opaque zone as “fractions” of the width of a completed increment cycle within an otolith.
Patterson et al. (1998) observed that the microchemistry of otolith sections of Lutjanus bohar at age -0 having difference that can be used for long term movement of fish
Newman et al. (1996) determined the age and growth of Lutjanus adetii and L. quinquelineatus from Great Barrier Reef through annuli observed in sectioned otoliths (sagittae) validation for L. adetii from tagged fishes, recaptured after a minimum of 12 months durin g the study they observed single opaque and translucent zone once a year, with the opaque band (annulus) during winter months with significant differential growth between the sexes in length-at-age and weight-at-age for both
77 species, with males growing larger than females and oldest individuals a male of L. adetii of 24 years of age and a female L. quinquelineatus of 31 years of age.
Morales-Nin et al. (1989) age and growth of Lutjanus kasmira (Forskål) in Hawaiian waters through examination of otoliths and by analysing length-frequency distribution and observed the annual hyaline and opaque markings in whole mounts of sagittae, further verified by enumeration of daily increments with a scanning through electron microscope (SEM) and marginal increment analysis
Ralston (1983) studied the microstructure of otolith in Hawaiian snapper, and observed the growth increments deposited daily in immature fish (<40 cm FL and <3 yr of age) with tetracycline-injected fish and analysis of modal progression in size- frequency distributions can determine otolith growth rate by measuring increment width based on the relationship between otolith growth rate and otolith length, by using regression analysis, a model is developed relating otolith growth rate to otolith length shows integration of the regression equation provides estimates of the age of individual fish, assumptions involved in the model.
Williams (1974) discussed age and growth of Lutjanus johnii and estimated by counting annuli at otolith sections, whole otolith, scales, with the comparisons of linear for estimation of age is a best technique and the positions of presumed annuli relative to tetracycline (OTC) marks were measured for two younger fish.
2.5.2 Based on fish scale
Marcela Sarabia-Méndez et al. (2010) observed the maximum period of growth ring formation in the scales of L. guttatus, indicates a growth ring is formed per year and scales are valid to determine age of Lutjanus guttatus.
Gallardo-Cabello et al.(2010) analyzed the age and growth of Lutjanus peru (Lutjanidae) through semi-rectangular ctenoidea scales to determine the age and growth, formed in February, formed due to several factors, such as low temperature, changes in the fish condition factor and reproduction activity and because of these
78 factors, with or in addition to horizontal distribution and bathymetric migrations, also “false rings” are formed on the scales that can be recognized because they are not complete around the scale with several aggregated lines, have a dens structure that does not allow the light and distance between growth rings diminishes as age increases, which is in agreement with the fact that rate of accumulation of structural components on the scale has an inverse relation over time and growth of scale is related to the fish length faster growth takes place during the first stages of life before sexual maturity through four growth rings, obtained with indirect method through vonBertalanffy’s growth equation obtained by simple linear regression.
FIscher (2007) provides an overview of age and growth of Red Snapper in the Gulf of Mexico to “further clarify and describe the life history of red snapper, evaluated the comparability of age determination utilizing different hard parts including whole otoliths, scales, and vertebrae.
Cappo (2005) used scales, otoliths, opercular bones, fin rays and vertebrae for determination of age and growth of Lutjanus sp, and described the age and growth from any bony structure is bassed on assumptions that periodic feature are found at the constant frequency and distance between consecutive features such as circuli or annuli is propotional to fish growth.
Rodriguez (2003) discussed age determination in Lutjanus guttatus (Pisces, Lutjanidae) and fishery management strategies in the Pacific Coast of Guatemala and observed the scales shows lack of clearness in the ring formations, and the use of scale abandoned as a possibility to age the fish.
Marriott and Cappo (2000) discussed the five different ageing methods for Lutjanus johnii through hard parts and scales were selected from the skins in the vicinity of the pectoral fin base, washed and dried, and found inter pretable ring patterns on scales, the unbroken radial rays joined at thefocus, chosen for estimating “scale age” using a microfiche reader at10X magnification.
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Bortone and Hollingsworth (1980) studied the age of red snapper in comparison of whole scale, otoliths, and vertebrae by revealed all three hard parts to be of equal utility in aging red snapper at observed age 1 and 2 yr.
Druzhinin and Filatova (1980) discussed the age and growth of Lutjanids and given comparisons of growth parameters and longevities in among Lutjanid are difficult because age estimates are based on different methods and the growth rate is dependent on an accurate estimation of longevity. The mean age of species of the genus Lutjanus when using sectioned otoliths is 21.5 years, which is nearly double the age estimate of 11.5 years from studies using scales.
Wade (1981) discussed the age and growth of red snapper through anulli observed on scales for age determination of red snapper(Lutjanus campechanus) .
Nelson and Manooch (1982) reported red snapper ages from 1 to 16 yr on the basis of scales and sectioned otoliths and demonstrated once yearly scale annulus formation in June and July from monthly mean marginal growth.
Mosley (1966) used annuli of scale for determination age of red snapper from west coast of Florid, counted “growth rings” to obtain ages from zero to four years and sugged an accelerated growth rate during the first year, observed the distance of growth rings to the periphery of the scale to determine timing of ring formation and reported the scale impressions of June sampled fish displayed new checks indicating that growth ring formation may coincide with the spawning season in late spring or early summer.
2.6 Population dynamic Parameters
Courtney et al. (2013) discussed population dynamics parameters of Red snapper (Lutjanidae) from Eastern Gulf and observed the decline of red snapper is almost certainly attributable to overfishing, but the cause of the population increase in the northern and western Gulf, as impact of artificial reefs.
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Shimose and Nanami (2013) investigated the population dynamics parameters and distribution patterns of Lutjanus sp (Perciformes: Lutjanidae) in the Ryukyu Islands, Okinawa, Japan, through fish market surveys/collections about 19 species of Lutjanus discussed where five species were commonly found in 1.0% frequency of occurrence from south Ryukyu Islands to around Okinawa Island and two species (L. decussatus, L. rivulatus) that were observed commonly at Ishigaki but not at Okinawa, three species of genus Lutjanus (Lutjanus bengalensis, Lutjanus stellatus) not common were thought to have main distribution outside the Ryukyu Islands and the remaining five species (Lutjanus malabaricus, Lutjanus vitta) were observed common at Okinawa but not at Ishigaki, despite the fact they are widely distributed in the area south of the Ryukyu Islands further they reported the environmental condition, habitats around Ishiagki are not fit for nursery grounds and adults.
Syc et al. (2012) studied the habitat of red snapper (Lutjanidea) and discussed distribution pattern and also classified the red snapper associates with older at artificial reefs.
Kevan et al. (2012) discussed the population structure of Red snapper (Lutjanus campechanus) from age composition of harvest and landings at Gulf of Mexico.
Ali Fakhri et al. (2011) discussed the stock assessment and population dynamics parameters such as mortality, Exploitation and yield per recruit of Javelin Grunter, Pomadasys kaakan and Length-weight relationships, growth estimation and length at age of Lutjanids in Iranian waters.
Rajapackiam et al. (2011) Provided the details regarding population dymanics and landing of Lutjanus malabaricus at Chennai Fisheries harbor through mechanized gillnet along with other Lutjanus species (L. rivulatus and L. malabaricus) was dominant catch (29.9%). In, L. rivulatus (33.7%) formed the major catch followed by L. malabaricus and Pinjalo pinjalo.
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Peterson (2009) discussed the stocks assessment and reproduction of lutjanus compechanus in Southern East U.S.A and Caspian.
Grandcourt (2008) discussed the population dynamics parameters and stock assessment of emperor red snapper (Lutjanus sebae ) on the Seychelles Bank by yield-per-recruit (YPR) and spawner-biomass-per-recruit (SBR), parameters were derived from size frequency and size-at-age data from validated annuli in sagittal otoliths.
Amin (2006) studied the population dynamics parameters of lutjanus lineolatus from bitter lakes suez canal, Egypt, through estimation of age and growth, mortality and exploitation of lutjanus lineolatus, the age was determined by growth rings by otolith, length, total mortality and exploitation rate were calculated, Hay (2005) discussed indetails the population dynamics parameters for Golden Snapper.
Knuckey et al. (2005) studied the distribution and habitat of Golden snapper with the special reference to Populationdynamics parameter and Biology.
Mehanna (2003) estimated the age, growth, and mortality, relative yield per recruit and relative biomass per recruit of Lutjanus lineolatus from the Gulf of Suez during 2001-2002.
Newman (2002) invstigated the growth, age validation, mortality, and population characteristics of the red emperor snapper, Lutjanus sebae, from Kimberley coast of North-Western Australia, the growth estimated through von Bertalanffy growth curve to lengths-at-age for all L. sebae, and separately for each sex, L. sebae is slow to age 8, with growth in length much reduced beyond the 8+ age cohorts. Length-at-age of L. sebae was significantly different between sexes
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Hector and Andrade (2003) and Brute, et al. (2003) studied the growth mean of fish and reproductive biology of Lutjanus fulvi (Lutjanidea).
Hajisamae and Chou (2003) investigated the impact of shallow water habitats of coastal strait serve as nursery grounds for fish such as many coral-related species, Lutjanus johnii, Saurida spp. and Siganus virmiculatus.
Newman et al. (2000) investigated the population dynamics parametesr of L. erythropterus, L. malabaricus and L. sebae and discussed the age, growth, mortality rates and corresponding yield estimation of from the central Great Barrier Reef.
Blackwell et al. (2000) discussed estimation and population dynamics, age and growth rate and mortality of Lutjanus sp.
Laidlay (1997) provided the details regarding restoration of population of lutjanus ccompecanus, including reproductive biology and growth rate of fish during specific period in rearing tank.
Romero et al. (1996) discussed the population dynamics parameters growth, maturity, fecundity, mortality and stock sizes of Lutjanus species (Lutjnaus peru, Lutjanus argentimaculatus and Lutjanus guttatus) from weekly sampling.
James (1996) investigated the exploitation and biology of Snappers Lutjanus argentimaculatus, Lutjanus johnii, Lutjanus vita, Lutjanus malabaricus, Lutjanus Sanguineus and Lutjanus fulvus in India.
Arriaga et al. (1996) studied that ecological impact, population dynamics and life history of Lutjanus synagris on Campeche Bank at continental shelf adjacent to lagoons during trawl catch (2.5 cm at mouth and 1.90 cm ay end mesh size).
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Pauly et al. (1996) compiled the findings of the three working groups (population dynamics and ecology; fisheries management; biology and aquaculture) of the International Workshop on Tropical Snappers and Groupers organized by EPOMEX and ICLARM.
Mees (1993) reported the population biology and stock assessment of Pristipomoides filamentosus (Lutjanidae) on the Mahé Plateau and stock assessment of tropical demersal fisheries in Seychelles waters during six collections of mother ship/fishing boats for analysis of commercial line fishing data to estimate the stock production of specific area.
Sparre and Venema, (1998) ; Evan, et al., (1994) ; Albert (1992) ; Garcia, et al. (1989); Francis, et al.,(1988) ; Pauly (1987) ; Parrish (1987) Nelson (1985) ; Edward (1985) ; Lu Suifen,(1981) ; Jaleel (1978) ; Grimes (1978) ; Bashirullah, (1975) ; Rao(1965); Swingle,et al.(1965) ; Von Bertalanffy (1938) also discussed biology, population dynamics parameters and growth of Lutjanids.
2.6.1 Growth
Black (2011) provided basic information for growth of Lutjanus capechanus and Lutjanus gresus (Lutjanidea) through tree rigns analysis technique to determine growth of red snapper and gray snapper.
Marcela Sarabia-Méndez (2010) studied the population dynamics of Lutjanus guttatus (Lutjanidae) in Bufadero Bay, Michoacán, Mexico and the weight for every age with the growth data in length were obtained for Lt and L∞ for W and W∞, in von Bertalanffy´s (1938) equation and observed the maximum period of growth ring formation in scales.
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Grandcourt (2008) estimated the growth of Lutjanus sebae (Emperor red snapper) from Seychelles Bank through fitting von Bertalanffy growth (VBGF) function to size-at-age data, using non-linear least-squares regression.
Beyer (2008) determined the age of red snapper, Lutjanus campechanus through shape analysis otolith annular increments through mark and recapture study and observed the reading transect was slightly altered from a radius immediately next to the sulcus and false increments observed, showed two rings formed during one year.
Andrade Fernando Martinez (2003) compare the growth rates of snappers (Lutjanidae) of different sizes, growth models of three arbitrary categories (small, medium, and large) were constructed using the von Bertalanffy growth equation, and the mean values of the life-history variables of small species L. quinquelineatus, L. lutjanus, L.fulviflamma, L. decussatus, L. notatus, L.adetii, L.vitta, L.kasmira and L.carponotatus medium species L.apodus, L.buccanella, L.erythropterus, L.griseus, L.mahogoni, L.monostigma, L.russelli, L.stellatus, L.synagris, and Rhomboplites aurorubens and the largest species L.cyanopterus, L.argentimaculatus, L.sanguineus, L.campechanus, L. purpureus , L.analis, Lutjanus sebae, Lutjanus jocu, Lutjanus johnii and Lutjanus malabaricus he further discussed the comparison of three groups of snappers within the subfamily Lutjaninae and observed the larger species had lower growth rate (0.163/year) than medium (0.212/year), and small species (0.397/year).
Abbas (2002) observed the growth parameters and body composition of juvenile’s of red snapper Lutjanus argentimaculatus (Pisces, Lutjanidae) reared in sea water tank at Sindh.
Hussain and Zakia Khatoon (2000) studied the the culture of Lutjanus johni and Pomadasys kaakan in floating cages at Karachi coast, three types of cages were used, 1) n square shaped cages (1×1×1 m) made of teak wood, 2) rectangular cages (1.5×1×1 m) and 3) rectangular cage with net hanging free in the seawater, cages were subjected to durability test and the rate of fish survival in the cages was determined during the observations they studied the growth in (i) monoculture, where Lutjanus johni and Pomadasys kaakan were kept in separate cages, and (ii) bi-culture, where
85 the 2 species were kept in a single cage. Lutjanus johni and Pomadasys kaakan given better results with monoculture (85 g and 131.7 g mean gain in weight/fish, respectively), than in bi-culture (44-48 mean weight gain/fish).
Hussain and Abbas (1995) studied the influence of feed levels on the growth of Lutjanus johni (snapper), Pomadasys kaakan (drum) and the growth of lutjanus johnii and P. kaakan in three types of fleeting eggs are square and rectangular shapes regarding monoculture of bi culture from result for culture of growth species.
Davis and West (1993) the growth of of Lutjanus vittus and observed significantly difference in male and female of L. vittus after 3 years of age and female L. vittus were observed to grow at a slower rate, and slight growth.
Lim et al. (1985) investigated the growth rates of larvae of lutjanids Lutjanus griseus and the Indo-Pacific Lutjanus johni through a laboratory and only significant data on growth rates of a larval lutjanid ob both species were found at laboratory-reared specimens of the Tropical-Western Atlantic species.
2.6.2. Mortality
Grubert et al. (2013) investigated the status of stock assessments of selected Northern Territory Fishes in reference to contribution of Golden Snapper for commercial catch and reported the Golden Snapper are the second most frequently caught fish after barramundi, with the total annual catch (as distinct from harvest) by this group over the last ten years ranging from ~13 000 to ~20 000 individuals, an average fish weight of 0.9 kg, this equates to between 11.7 t and 18.0 t of Golden Snapper caught, with an unknown proportion succumbing to incidental mortality.
Heupel et al. (2010) investigated the demographic characteristics of exploited tropical lutjanids and provides a comparative analysis of total mortality (Z) estimates calculated from catch curves varied significantly among the five species of Lutjanidae. Total mortality Z was highest for Lutjanus gibbus and lowest for Lutjanus
86 fulviflamma. Hoenig method was used for calculation of mortality rates, the mortality estimates from catch curves.
Marcela Sarabia–Méndez et al. (2010) discussed the popultaion dynamics parameters of Lutjanus guttatus (Lutjanidae) and reported the age determination is one of the most important objectives of fish population dynamics, and very help full for population structure by age groups, longevity, recruitment age, sexual maturity and captures, the determination of age allows studying the growth or the study of mortality or diminution of the biomass, the method employed more frequently for age determination is growth rings identification in hard structures as: scales, otoliths, vertebrae and spines.
Heupel et al. (2009) given compression of biological charaters including size, age, growth, mortality and reproductive patterns of several Lutjanids species occurring on mid and outer shelf reefs of the Great Brier Reef (GBR) included the china man (Symphorus nematophorus), green job fish (Aprion virescens), blackspot sea perch (Lutjanus fulviflamma) hussar (Lutjanus adetii), paddle tail (Lutjanus gibbus), striped sea perch (Lutjanus vita) and stripey (Lutjanus carponotatus).
Marko et al. (2004) and Zhang, et al. (2004) discussed the issue of over fishing and mortality of Lutjanids (Lutjanus malabaricus, Lutjanus erythropterus, Lutjanus argentimaculatus, Lutjanus stellatus, and Lutjanus sebae).
Newman (2002) estimated the rate of total mortality (Z) of Lutjanus sebae from catch-at-age data where the nnual catch in weight was converted to annual catch in numbers-at-age through age frequency data to obtain catch per age class and catch in weight converted in to catch in numbers based on the mean weight of each year and mortality estimation derived between successive years by obtaining the natural logarithm of the catch per age class.
Pauly et al. (1995) discussed the standard techniques for estimation of total (Z) and natural mortalities (M) can be usually applied to groupers and snappers, and discussed the methods for improving the estimation of mortality (M) and estimation
87 of (Z) by using length-converted catch curves which explicitly account for seasonal growth oscillations and individual growth variation.
2.6.3. Recruitment
Murguan et al. (2014) investigated the status of snapper during survey of nine fish landing centres (Pamban South, Mandapam South, Keelakarai, Ervadi, Vembar, Tharuvaikulam, Thirespuram, Tuticorin and Amalinagar) along the Gulf of Mannar region, total of thirty species of fishes belonging to the family Lutjanidae (snappers and job fishes) belonged to five genera viz., Lutjanus, Pinjalo, Aphareus, Etelis and Pristipomoides, they recorded 43 species of snappers from Indian waters, 22 from Cochin waters, 17 from Mandapam,11 from Vizhinjam, 10 from Veraval and 6 from Visakhapatnam, \from the Srilankan waters includes Gulf of Mannar , thirty (30) species of family Lutjanidae has been recorded from Gulf of Mannar and major reason regarding high diversity of snappers might be due to the interrelationship between coral reef, seagrass, rocky substratum and mangrove ecosystem reported.
Aburto-Oropeza et al. (2009) examined the recruitment and ontogenetic habitat of the yellow snapper Lutjanus argentiventris in the Gulf of California in mangroves, where juveniles remain until they are approximately 100 mm in length or 300- days- old and reported major recruitment peak during September and October, around 8 days before and after the full moon in the light of back-calculated settlement dates and underwater surveys. Russell et al. (1999) studied the genetic stock structure, biology and management of Mangrove Jack, (Lutjanus argentimaculatus) from Australia and discussed variability in recruitment of juvenile fish into rivers occurs from year to year and observed the recruitment into inshore areas occurred in the first part of the year and early juveniles were usually found close to the river mouth, before moving progressively upstream. Juveniles that are newly recruited into rivers (20-30 mm LCF) were more commonly associated with rocky habitat. 2.6.4 Age
Yamada (2010) determined the age and growth of Lutjanus argentimaculatus (mangrove red snapper) through growth rings found on sectioned otiliths and monthly
88 marginal growth index which indicated that the opaque zone formed once a year, and suggested that smaller fish moved from river to the coastal area to increase in size and described the fish Lutjanus argentimaculatus (mangrove red snapper) of 1 to 3 years lived in coastal habitats and somatic and otolith growth was faster in 1 to 3 fish live in coastal habitat as compared to rivers habitat
Hurley (1997) described back calculation of length at age determination from two scale radius, one horizontally from the focus to the anterior-median age and secondly diagonally from the focus anterior lateral corner further they reported that actual place of scale removal and measurement techniques can cause variability in back- calculation length-at-age estimation.
Goodyear (1997) discussed the accuracy and precision of estimates of catch of red snapper, Lutjanus campechanus evaluated for three different methods, included a growth curve, age-length keys, and a probabilistic method, 1) ages were estimated from sample lengths directly from the growth curve, 2) involved expanding the sample length frequency to age frequency by using age-length keys, 3) probabilistic method incorporated the cumulative frequency distributions of length at age, year- class strength, and estimates of prior survival. The probabilistic method was observed as the best of three for situation evaluated.
Devis (1992) discussed the moratlity of Lutjanus vittus and no significant differences observed in the instantaneous rate of annual mortality (Z) between male and female L. vittus.
Ralston (1987) discussed the age and life span of snappers and described in the study of age and growth from sectioned otoliths the snappers are long-live (up to 53 years) fast growing fishes.
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MATERIAL AND METHOD
3.1. Specimen collection and Sampling Sites
Specimens of Lutjanus lutjanus and Lutjanus johnii were collected during three years study (2005-2007) from three main landing centers of Karachi Sindh as below: 1. Karachi Fish harbor (Large landing centre of Karachi) 2. Ibrahim Haidry 3. Rehri village Karachi Through boat collections specimens were collected on monthly basis from five different stations of Korangi creek area ( Gangyaro creek, Phitti Creek, Khuddi Creek Khai Khuddi Creek and main channel of Ibrahim Hyderi) (Figure 3.1 and 3.2). The Korangi-Phitti Creek (KPC) system (24°45′N, 67°20′E) near Karachi is a very productive area of near shore line/ creeks due to the presence of dense mangrove small scale fishing is found by local fishermen, due to the shallow water area and shelter zone small fishes/ juvenile) are live frequently in the habitat of this system. In present study the specimens were caught through trawl net and trap net about 10-35 ft to 50 ft width at tail , 150 ft length with mesh size ½ to 2 ¾ inches on 32ft length fishing Boat on monthly basis This Korangi, Phitti creeks is 20 km in length, 1,350 m wide has average depth of l5 meters. It is a complex network of Korangi and adjacent creeks has vast mangrove dominated areas which create a highly productive ecosystem.
Figure 3.1 Specimens collection from Phitti creek (Korangi creek area) Karachi East.
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Figure. 3.2. Complete Map for collection sites.
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3.2 Identifications and measurement
Collected Specimens were identified with the help of Field Guide to the Snappers (Lutjanidae) of western Atlantic by Anderson (2001) identification sheets by Eschmeyer in Fish base (1984) and Field Guide to the Commercial Marine and Brackish water species of Pakistan/ FAO species Identification sheets by Bianchi (1985) total length (TL) were measured nearest to 0.1 cm and weight nearest to 0.1 gm.
3.3 Size classes
After Identification and detail observation specimens were measured total length (TL) from snout to tip of Caudal fin and fork length (FL) from snout to middle notch of caudal fin nearest about 0.1 cm then weighted in gm.
Scales were taken out from the region of lateral line just below the tip of first dorsal fin and otoliths were taken out from the head region, washed, dried and weighed on “OHAUS” electronic balance with the accuracy of 0.1gm.
Size class were made by the formula given by, Zuwaylif (1979)
No of classes = 1+ 3.3 log N
Where N = number of observations And class width determined by the following formula Highest Variable – Lowest Variable / No of Classes
No of classes = 1+ 3.3 log N Where
N = number of observation. And class width was determine by the following formula Highest Variable – Lowest Variable / No of Classes
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3.4 Macroscopic observation
After identification, specimens were observed in detail visually, about damages of body, scale, fins, skin etc due to miss handling by fishermen and presence of ectoparasite under the gill cover.
3.5. Reproductive biology
Reproductive biology of both specimens was studied by dissection from belly of specimens collected from different locations of coastal belt in different months to collect the gonads. Several researchers discussed the reproductive biology and agreed that the Lutjanids are gonochoristic, sexual maturity recorded at 40 to 50% length maximum approximately. Basically two seasonal patterns are reported in snappers, especially in Lutjanids (a), summer season, and (b), year around spawning and peek in spring and fall, depends on habitat where population found such as oceanic, islands or continental margins (Druzhinin, 1970). Snappers have continental habitat may be timed to coincide at production cycle and at small island snappers spawn all round the year and reproduction in pelagic and demarsel habitat fish face major problems to their larvae. Lambert and Ware, (1984).
3.5.1. Analysis of gonads
Body cavity of the fish was dissected to obtain the gonads; physical appearance and maturity stage of each gonad were observed on the bases of classification of Buxton (1992), the smaller size of fish where sex was not determined termed as immature or unsexed. Each month 20 gonads of wide size range were fixed in Davidson's fixative for 48 hours and dehydrated through the series of increasing concentration of ethanol. Middle region of the gonad were selected for transverse section but in some cases anterior and posterior were also used. The section was embedded in paraffin wax; section of 7µm thick was prepared and stained with Delafield's Haematoxylin and Eosin (as counterstained). For detail examination, microphotographs were taken with the help a digital camera (Olympus) attached to the microscope by 10x to 40x magnification. Histological technique is helpful to assign the accurate stages of maturity. Histological classifications of gonad development are based on the scheme used by Hesp (2003).
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3.5.2. Classification of maturity stages based on macroscopic analysis.
The gonads of both species .i.e. L. lutjanus and L. johnii were examined and observed carefully for their classification at different maturity stages based on visual examination as given by Garrat, (1985) and Buxton (1990) with minor modification (Table.3.1 and 3.2).
Stages of Female Male maturation Immature / Inactive Ovarian zone is elongated, thin, Testicular zone is elongated rounded pinkish yellow or orange and whitish / pale in color translucent in color.
Developing/ Active Ovaries are larger, yellow /orange Gonads larger, opaque to in color. Oocytes can observed milky whitish.. through the ovarian wall.
Mature /Ripe Thick and larger in size, fully Thick milky whitish gonads (Spawning Stage) packed with hydrated occytes were observed at this stage ovarian wall with granular testicular zone is appearance. Gonads were predominated Milt oozes occupied about the whole length when pressure usually put of the body cavity, it is difficult to on the abdominal region. distinguish the degenerated testicular zone but careful examination showed that the thin translucent band of testicular tissues is founded on the dorsal side of the gonadal wall.
Spent Ovaries shrieked and become Generally gonads become flaccid, dark reddish brown in smaller in size rather than color with few yolk granules larger as juvenile’s gonads. visible through gonad wall.
Table 3.1 Visual observations of maturity stages of L. lutjanus and L. johnii.
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I and II Immature, Virgin Oogonia with primary growth oocytes were present. and resting Ovarian lamella highly organized. In resting ovaries, Scare tissues present no yolk granule oocyte present.
III- Developing Primary growth oocytes predominant with less advance stages cortical alveolar oocytes present.
IV- Maturing Mostly yolk granule acolytes with cortical alveolar oocytes present.
V/VI- Fully mature or Largely yolk granule oocytes predominant along with spawning hydrated oocytes with hydrated oocytes and few posts ovulatory follicles present.
VII- Partial Spent Yolk granule oocytes, Hydrated oocytes with typically undergoing atresia present.
VIII- Spent Scare tissues and post ovulatory follicle predominant.
Table 3.2 Description and classification of the Histological observation of female maturity stages of L. lutjanus and L. johnii. Histological examination donned on the bases of classification as given by Laevastu (1965) with slight modification.
3.5.3 Gonadosomatic Index (GSI)
The maturity stages of both species assigned based on the description of Laevastu, 1965. The Values of gonadosomatic index (GSI) of both species were calculated on monthly basis by giving of equation, Hesp et al., (2004)
GSI-W1/ (W2-W1) X 100
Where as
W1 = wet weight (wt) of Gonad
W2 = wet (wt) weight of fish
W2-w1= Somatic weight
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3.5.4. Estimation of L 50% Sexual Maturity
Length at 50% of individuals attained maturity for both species by sex were calculated by using the individuals with III, IV and V stages of gonad, which were observed during the spawning seasons, population of mature males and female individuals by size class were used as input in logistic regression analysis to estimate the length at 50% maturity. Estimate the size at first maturity (TL where 50% of the individuals are mature). The logistic curve was fitted by nonlinear regression.
Pi 1 1 + e –b (Li – L50) Where; The pi proportion of mature in Li, L50% is the size when 50% of size class individuals are mature and b is constant.
3.5.5. Fecundity
The mean count of three sub samples were calculated and used to estimate the total numbers of oocytes found in the gonads of each fish. During the peak spawning season the ripe females were randomly selected in the month of (September- December) and ovaries were weighted by electrical balance nearest to 0.001 gm and then placed in Gilson’s fluid till breakdown of ovarian connective tissues (about 5 to 6 months). The gonads were shaking twice in a week. After 5 to 6 months, ovarian connective tissues were completely broken down now one by one by content sieved through 600µm mesh size to remove the remaining unsolved ovarian connective tissues and again sieved with 125 µm mesh sizes, the remaining material was consist of mature oocytes. The oocytes weight to the nearest 0.001 gm. Three repeat random samples were weighed to the nearest 0.05gm, count the oocytes at x 10 magnification by binocular, and calculate the mean of it. Fecundity was estimated by formula (Hunter, et al., 1992) is given below:
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F = W/w x N Where:- F = Estimated fecundity W = Total oocytes weight w = Sub sample weight N = Number of oocytes found in the sub sample
The relationship between total weight (Wt) in (gm) and total fecundity was estimated by following power equation
F= aWb or logF = loga + b log W Where = F = Estimated fecundity W = Weight of fish a and b are constants
3.6 Otolith
About 50 (fifty) specimens from different size class with (Total length 10 cm, 28gm; 15cm, 60gm; 20cm,110gm ; 25cm, 230gm and 27cm, 308wt) for L. lutjanus and for L. johnii (15cm,60gm; 20cm,105gm; 25cm, 228gm; 30cm,535gm;35cm,676gm; 40cm,832gm; 45cm,3300gm; 55cm; 4250gm, 60cm;5210gm; 65cm;5660 gm and 70cm; 6256 gm wt) were used for each species for study of growth rings after section cutting of otolith which were finally clear and visible sections were studied. Otolith (ear stones) from both sides were removed immediately after dissection with the help of pointed and sharp seizer from cranium (head) and optic bulla, where otoliths were found, washed with fresh water to remove the blood, lymph fluid and any other material, air dried and stored in airtight plastic bags for further analysis Figure 3.3 (A) and (B), details/ information about specimen such as date of collection, location, weight (gm) Length (cm) etc were marked. Earlier studies about ageing by otolith shows, there is no difference between right and left otolith structure (Campana,1992; Casselman, 1990; Goncalves, et al., 2003 ., and Zorica, et al., 2010). Left otolith was used but if left was broken right was used to avoid error cleaned and undamaged otoliths were dried in 1 hour in t 40°C. The dried otoliths weighted by using an electronic balance (Libror-Aeu-210) nearest to 0.001 g (WO) and otoliths length 97 measured by the caliper at the longest dimension between the posterior and anterior edges, measured nearest to 0.05 mm (LO). Otolith radius measured in millimeters (mm) using computer software (Scope Tack) by a fixed scale in software and pictures of whole otolith were taken by stereo microscope having microstructure (Maiji, Zome Stereo, EMZ-2) eye piece for determination of age method was used given by Chugunova, (1963) and discussed by Morales-Nin(1989).
A B
Figure 3.3 (A). Cavity of cranium of Lutjanus Lutjanus , 27cm (TL) where otolith were found. (B). Inner portion of head region of Lutjanus johnii 42cm (TL) dissected for otolith.
For analysis of growth rings through section cutting, the 50 samples with different size TL (cm) and weight (gm) of each species were used. The otoliths were mounted in transparent Epoxy resin, Bedford (1977); Wright, et al, (1990). The embedded otoliths were sectioned with the help of MICRACUT 125 (low speed precision cutter), 2 to 3 sections of 0.8, 0.7, and 0.5 mm thickness were obtained and ensure that at least one section may pass through the core (center, nucleus). The sections were washed with distilled water and etched with 1% HCl and reined properly with distilled water, air dried and mounted on a clean glass slide with DPX (mounting medium) and directly immersed in a glycerin fill Petri dish, then digital images taken against a dark background with camera (Olympus) attached with stereo-microscope viewed with different magnification. The digital images and the sections were analyzed by image analysis software’s (Olympus DP-Software and Image J) to estimate marginal incensement reads in mm by fix scale in software and counted the annuli. Each otolith section read by two independent readers separately and counted
98 the opaque growth zones on each sectioned otolith without any knowledge of length, weight and month of sampling. If the counts were different then the section were analyzed again.
3.7 Validation of age
The growth zones found at sectioned otolith were counted for age estimation and monthly marginal growth increase (MI) was determined by following equation. Determination of marginal increases (MI) were made by the distance between focus (R) or primodium and the outer edge of the single opaque zone if one growth zone was found and the outer margins of the two outermost growth zones when two or more opaque zones were present. All measurements were taken along the same axis (Hyndes, et al., 1996). Distance between last opaque zone (Rn) and between Focus to second last opaque zone (Rn-1) were measured in millimeters.
MI = R - Rn / Rn - Rn-1 Where;
MI= Marginal growth increment. R= Radius of otolith (mm). Rn= Distance between focus to last opaque zone. Rn-1= Distance between focus to 2nd last opaque zone.
Relationship between fish total length (TL) in cm, otolith length (mm) and radius (mm) were determined by Micro soft excel and visual observation radius measurement of otolith and Image J, Scope Tack software. For this purpose, measurements from the distance relating to the core or focus point to the edge of the otolith in case of single opaque zone was found and if two or more than two opaque zones the distance from the two outer most zones and distance from the outer margin.
3.8 Validation of Length frequency data
The length frequency data were derived from three years (2005-2007) collection of two species (L. lutjanus and L. johnii) and analyzed by ELEFANI I routine of FiSAT (FAO- ICLARM Stock Assessment Tool) (Gayanilo et al., 1996). The length 99 frequency data were used for von Bertalanffy growth parameter Lt = L {1-e –k (t-t0)} estimation by plot, Gulland and Holt (1959). The Growth performance index (ø) estimated by (Munro and Pauly, 1983) method using L∞ and K values derived from each species.
ø =lnK + 2 ln L∞
The subroutine of FAO- ICLARM Stock Assessment Tool (FiSAT) software Gayanilo et al. (1996) was used to estimate the population parameters i.e. Recruitment parameters, virtual population analysis (VPA), mortality rates, yield per recruit, biomass per recruit and isopleths analysis. The total mortality coefficient (Z) determined by the linear length converted method. The final estimate of L∞ and K used with length distribution data for the both species (Gayamilo and Pauly, 1997). Fishing mortality was calculated by formula given below, (Gulland, 1983).
E=F/Z and U =F/Z (I-e-Z)
Natural mortality (M) was estimated by using Pauly’s (1980) formula and average seawater temperature of the area was assumed 26oC. The biomass per recruit, probability of capture and yield per recruit were obtained using length converted catch curve by extrapolating backward and Lc was constant. The different length of the first capture values of Y/R and exploitation ratios was plotted to generate the isopleths diagram. The yield was estimated by the knife edge selection method using the equation of Beverton and Holt (1957).
For the observation of recruitment, pattern the values of growth parameters L∞ and K used as input. Different recruitment peaks were examined in recruitment pattern. The modified predict the relative yield per recruit of species.
3.9. Length-weight relationship analysis
Total length (cm) and Total weight (gm) of specimens were measured to the nearest 1cm (TL) and weighted to the nearest 0.01 (gm) the length- weight relationship
100 analysis of both species were estimated By the well-known allometric model in fisheries is defined: W = aLb (Ricker, 1973)
Where “L” and “W” represent the length and weight of fish respectively, ‘a’ and ‘b’ are parameters Data transformed into a log and now the equation is
Log10 W = a + b log10 L (Zar, 1996)
Where:-
W = weight (g) independent variable. L = length (cm) dependent variable And a = is an intercept; n = is a power function of the length – weight relationship.
Log Total length (TL) in cm and log weight (WT) in gm used for estimation of length-weight relationship of males, females and combined per years.
3.10. Calculated Length Weight Data
Length weight relationship of Lautjanus Lutjanus and Lutjanus johnii analyzed by given formula:- Y=b+a, R 2 W= aL (Ricker, 1973) Log W = log + n log ( Zar, 1996)
Where W = weight in gm independent variable. L= length in cm dependent variable and a= an intercept n = power function of length weight relationship.
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TL (total length in cm) and WT (weight in gm) used for this purpose. Relationship between fish Total length (TL), otolith length (OT) and Image J, Scope Tack software was used for counts the growth zones.
The relationship of fish total length (TL, cm) to otolith weight (gm) and otolith radius (mm) were estimated by regression technique as used by Michael (2002).
TL = a + b (OR) Where:- TL = total length in cm OR = otolith radius in mm TL = a + b (OW) OW = otolith weight in gm
Relationship in both specifies, Lutjanus lutjanus and Lutjanus johnii were observed and obtained plots between Fish length (TL) Vs Fish weight WT, Fish length vs. Otolith size, Fish length (TL) Vs scale size and Fish weight (WT) vs. otolith weight (WT) also plotted.
3.11. Estimation of age and growth
The knowledge about age and growth of fish species is very much essential to contribute the fisheries resources/studies and the longevity of exploited stock, age composition of catch, age at sexual maturity, suitability of different environments for growth, pollution dynamics parameters and identifications of stock on basis of differences in growth rates.
3.11.1. Method for fitting von Bertalanffy growth parameters by linear regression analysis (Stamatopoulos and Caddy,1989)
The age and growth of both species i.e. Lutjanus lutjanus and Lutjanus johnii were estimated by von Bertalanffy Growth functions by sex on yearly basis. The method for fitting the Von Bertalanffy growth function to data on size at age was presented as linear regression method by Constantine Stamatopoulos and VONBIT software by following equation (Stamatopoulos and caddy, 1989). Lt = L {1-e –k (t-t0)}
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Where:- Lt = total length at age L∞ = mean of asymptotic length predicted by the equation k = growth coefficient (per year) t0 = hypothetical age when the fish has 0 lengths
3.11.2. Estimation of age and growth by VBGF curve through ‘R’ Statistical Software (Ross Lhaka and Robert Gentleman, 1996).
“R” statistical software was introduced by Ross Lhaka and Robert Gentleman, 2007 and received a lot of attention in the last five years. This program provides a wide variety of statistical analysis i.e. linear and non-linear modeling, classical statistics, time series analysis, classification and graphical techniques and is highly extensible. In present study this software also used for Von Bertalanffy growth curve and estimation of mean length and observed length at age.
3.11.3. Linear regressions by Microsoft excel program
This program (Window 7) used to estimate different relationships such as fish length (TL cm) vs fish weight(gm), fish length(TL) Vs scale size(mm), fish length(TL) and otolith size(mm), and fish weight(gm) Vs otolith weight(mg) for both species year wise for three years data.
3.12 Scale observations
Three to four undamaged, clean and dried scales were selected for study from the storage bag, arranged between the two clean glass slides, The distance from the focus to anterior transect of the radius of scale, (RS) were measured by caliper to determine the fish length at age (Smith, 1963).
From different size class scales were taken from beneath the tip of the pectoral fin from the same area of each fish (Schneider, et al., 2000). In tropical fishes the pectoral fin area of fish body has a tendency to protect the scales from external environmental effects as compared to the scales of other body regions. (Manooch, 1987).
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With the help of pointed forceps four two six scales were obtained just below the lateral line and beneath the tip of posterior extended pectoral fin (Schneider et al., 2000).
Selected scales were immersed in a solution for removal of mucous and skin, after cleaning the scales were air dried and kept in an envelope, labeled with essential record.
Four two five complete (undamaged) scales were selected for determination of age, immersed in a 5% KOH solution, then washed with tab water and clean with soft brush to remove the skin and mucus, scale transfer into 95% ethanol solution for dehydration (Schneider et al., 2000; Mustafa, 2005).
Air dried scales placed between the two clean glass slides and a drop of glycerin was placed on each scale, pressed and warped the both ends tightly with transparent tape. Each scale observed under the 10x – 40x magnification by binocular examine for analysis of annuls and measured the growth zones and took microphotographs for further analysis.
Scale length and radius were measured by caliper in mm unit. The total distance from the focus of scale to the anterior edge of an annulus were measured, scale radius R measurement was taken on the right anterior-lateral line. Relationship between fish length and scale radius calculated using formula given by (Lagler, 1956).
L = a + b S
Where
L = Fish length (Fork length was used)
S = Scale radius (mm)
Radius is the distance between the focus (F) of the scale and right antero - lateral angle.
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3.13. Population dynamics (FiSAT-II, 1.2.2 VERSION, FAO, ICLARM)
The basic parameter of stock assessment is a study of population dynamics and fisheries are based on stock of wild populations in habiting in their natural environments. The purpose of study of fish population dynamics of exploited stocks is to offer scientific advice on the possible range of options for rational exploitation. By increasing fishing effort, the yield can be increased to a certain level, but further increase d in exploitation level leads to reduction in yield and if the efforts is still further increased regardless of the reduction in total catch and the catch rates, stock under the exploitation may collapse and fishing industry may face the problem of rehabilitation.
3.13.1. ELEFAN 1 routine of FAO- ICLARM Stock Assessment Tool FiSAT II software, Gayanilo & Pauly (1997) and Gayanilo, et.al. (1996) attempt to combine the logic of Peterson method and that of model progression analysis with a minimum of subjective inputs (Pauly’s 1983). L∞ and K values were obtained through four options i.e. curve fitting by eye, response surface analysis, scan of K- values and automatic search routine. In this method growth parameters L∞ and K were estimated Von Bertalanffy growth equation (Von Bertalanffy 1938).
In present study the length frequency data was analyzed by using FAO- ICLARM Stock Assessment Tool Fi SAT II software ,Gayanilo et.al.,1996, Estimation of asymptotic length (L∞) and \ growth co efficient ( K ) were made.
3.13.2. Von Bertalanffy growth curve (Fi SAT- II, 1.2.2 version).
Von Bertalanffy (1957) estimated K and L∞ from age/ length data using the equation:- Lt = L∞ (1-e –k (t-t0)) Where: Lt = total length at age L∞ = mean of asymptotic length predicted by the equation k = growth coefficient (per year)
t0 = hypothetical age when the fish has 0 lengths
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3.13.3. Shepherd’s method
According to Shepherd (1987) and Isaac (1990) it is similar to ELEFAN I, designed to maximize a non-parametric scoring function. Two options for identifying optional values of L∞ and K are available: (1) response surface analysis and (2) scan of K- values. Shepherd’s method is defined by:
S = (sA2 + sB2)½ Whereas: sA and sB are the goodness-of-fit scores (stz) obtained with the origin of the VBGF in calendar time (tz) set to 0 and 0.25, respectively.stz is defined by:
St ź = Ni Where:
Ni = frequency for length group i Ti = D · cos 2 (t-ti),
D =(sin ( t)/ t)),
t = t/2,
t = tmax - tmin ti = tz - (1/K)·ln(1-(Li/L_)), and tz = (1/2_) · tan-1(sB /sA)
3.13.4. Powell- Wetherall plot (Powell, 1979; Wetherall, 1986)
Powell–Wetherall method allows estimation of L∞ and Z/K from a sample representing a steady-state population, as can be approximated by pooling a time series of length-frequency data.
(L-L') = a + b · L' Where:- L = ( L∞ +Ľ) 1+Z/K
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From which L∞ = -a/b, Z/K = - (1+b)/b
3.13.5. Analysis of growth increment data
Following methods were used for estimation of growth parameters.
3.13.5.1. Gulland and Holt plot (Gulland and Holt,1959)
This method was used for preliminary estimation of growth parameters from growth increments, based the VBGF, growth rate declines linearly with length, reaching zero at L∞ and residuals of the plot were used for inferences on seasonality of growth.
L= a + b· Whereas:
= Lr- Lm, = tr - tm, and L = (Lr+Lm)/2.
Where Lm is the length at marking (initial reading), Lr is the length at recapture, and tm and the corresponding dates. From these growth parameters can be estimated
L∞ = -a / b and K =-b The plot of residuals, re-expressed in %, and plotted against the midrange.
3.13.5.2. Munro’s method (Munro 1982)
This method, based on Munro (1982), uses growth increment data to estimate L∞ and K or K alone.
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3.13.5.3. Faben’s method (Fabens, 1965)
This method was used for estimating L∞ and K by predicting length at recapture (Lr') as suggested by Fabens (1965) based on the current parameter selection and the length at marking (Lm). The growth parameters are estimated by minimizing the sum of squares of errors (SSE), i.e. the squared differences between the observed lengths at second reading (Lr) and the predicted lengths (Lr').
3.13.6. Mortality
Mostly routine were used to estimate the mortality and related parameters incorporated in Fi SAT II require estimates of growth parameters as obtained from the previous set of routines in this study mortality were estimated by following routines 1) To estimate total mortality (Z) from steady-state sample. 2) To estimate mortality from natural causes (M), here assumed to be constant for all sizes.
3.13.6.1. Length converted catch curve
Annual instantaneous total instantaneous total mortality (Z) was estimated by length- converted catch curve of Pauly,1980 by using total annual length- frequency distribution of catch.
Ln (N/ ) = a+bt
Where, N= Number of fish in the length class
= Time required for the fish to grow from a lower to higher class interval
t = age at a give length
b = coefficient of total mortality (Z)
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3.13.6.1.1. Jones and Van Zalinge plot (Jones and van Zalinge, 1981)
The cumulative plot of Jones and van Zalinge is an early form of length-converted catch curve and these two methods thus share many common assumptions.
(CLi,_) = a + b · ln (L_-Li) Where:- CLi,_ is the cumulative catch (computed from the highest length class with nonzero catch) corresponding to length class i, and Li is the lower limit of length class i. The slope b, is an estimate of Z/K.
3.13.6.1.2. Beverton and Holt model (Beverton and Holt,1957)
This model, assumed that the growth follows the VBGF, mortality can be represented by negative exponential decay and that L is estimated from a sample representing a steady-state population. Z = K· (L_-L)/(L_-L') Where:-
L and K = Growth parameters (L') = cut-off length and (L) =mean length
3.13.6.1.3. Ault and Ehrardt Method
In this model an infinite life span for the fish of the stock being analyzed does not assumed an infinite life span for the fish of stock and thus is applicable to short lived species. z/k L∞-Lmax = A(L') L- L' A(Lmax) Where:- A(L') = Z(L'-L)+K(L_-L), and A(Lmax) = Z(Lmax-L)+K(L_-L)
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3.13.6.2. Estimation of Natural mortality rate (M)
Natural mortality (M) is estimated by two routines of Fi SAT II software:-
3.13.6.2.1. Rikhter and Efanov’s method (Rikhter and Efanov, 1976)
The variant of the Beverton and Holt, 1956, equation which relates longevity (tmax) with the Lmass/L∞ ratio (where Lmass is the mean length at first maturity), this model relates natural mortality (M) to the age at which 50% of the stock reaches the age of "massive spawning" (tmass).
3.13.6.2.2.Pauly’s Empirical Equation, (Pauly, 1980; 1984)
Annual mortality instantaneous natural mortality rate (M) was estimated by using the equation of Pauly, (1980), derived from 175 independent sets of estimates of M and predictor variables for most tropical species. The Temperature value in the fishing ground was taken as 26 ºC.
Ln(M) = Ln(L∞)+ Ln (K)+Ln(T)
Where:
L∞ is the asymptotic length (cm) K is the growth coefficient T is the mean sea temperature (ºC)
3.13.7 Recruitment patterns, (Moreau and Cuende, 1991; Pauly, 1983)
In this study the routine reconstructs the recruitment pulses from a time series of length-frequency data to determine the number of pulses per year and the relative strength of each pulse.
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3.13.8 Probabilities of capture (Pauly, 1983, 1984)
In present study FiSAT program used for Probabilities of capture to determine gear- specific selection curves.
3.13.9 Gill net selection
In this study gill net selection were used to estimate the probability of capture for mesh size mA and mB at a given length L is,
PA,L = exp (-((L-LA)2/(2·_2)), PB,L = exp (-((L-LB)2/(2·_2)) Where:- LA and LB (the optimum length for mesh sizes mA and mB respectively) are given by LA = SF · mA, LB = SF · mB, and Where:- SF is the selection factor computed from,
SF = (-2a)/(b·(mA+mB)).
The coefficients a and b are estimated from the regression:
ln (Ci,B/Ci,A) = a + b · Li Where:- Index i denotes length classes, and Ci,A and Ci,B are the observed catches (in numbers) for class i of gears A and B used respectively.
3.13.10. Virtual population analysis (VPA) (Gulland, 1965; Jones and Van Zalinge, 1981)
This method used for analysis of virtual population which allow the reconstruction of the population from total catch data by size, in routine modified from Jones and
111
Zalinge, 1981 to utilizes basically the same approach as the previous routine (age- structured VPA), but is adapted to accommodate length frequencies, the terminal population (Nt) given the inputs, from Nt = Ct · (M+ Ft)/Ft
Where:-
Ct is the terminal catch ( largest length class), starting from Nt, successive values of F are estimated, by iteratively solving,
Ci = Ni+_t · (Fi/Zi) · (EXP (Zi·_ti)-1) Where ti = (ti+1 - ti), and ti = to - (1/K) · ln(1-(Li/L_)) Where population sizes (Ni) are computed from Ni = Ni+_t · EXP (Zi)
3. 13.11. Relative Biomass per recruitment (Beverton & Holt Y/R analysis ) ( Beverton and Holt, 1966)
3 3 3 Y' / R E U 1 {1 ------+------} (1+ m) (1+ 2m) (1+ 3m) Where U = 1-(Lc/L_) m = (1-E)/(M/K) = (K/Z) E=F/Z
Relative biomass-per-recruit (B'/R) is estimated from the relationship B'/R = (Y'/R)/F,
While
E max, E0.1 and E0.5 are estimated by using the first derivative of this function.
112
Exploitation ratio (E) and exploitation rate (U)
The value of E was derived from
E= F/Z U = F/Z (1- e )
3.13. 12. Estimation of Yield per recruitment and biomass per recruitment.
In present study this routine was done by using Beverton and Holt (1957) yield equation, the smallest length in catch species yearly, male and female separately as well as over the three year period was taken as length at recruitment. The value of L∞ used to estimation, following two types of graphs was obtained:
o Knife – edge (exploitation ratio (E) vs. Lc / L∞ ) o 2D analysis (Exploitation Ratio (E) vs. relative biomass/Recruit)
3.13.13. Maximum length estimation (Lmax)
The maximum length estimated by this routine of FiSAT II where the sample max of fish (L max) in a population, based on the assumption that the observed max length of a time series of sample does not refer to a fixed quality but rather, represent a random variable which follows a probabilistic law.
In which the L max is estimated from a set of extreme value (L* the largest specimen in each sample by using the regression:
L*= a+ 1/a P Where bribability associated with the occurrence of an extreme value 1/a a measure of dispersion and L max is intercept of he regression line with the observation, P is a computed for any extreme value from
P= m/ (n+1), (Gumbel, 1954)
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3.14.Growth performance indices.
The growth performance index The parameters [=log K + 2/3 log L∞ k100] have shown to be remarkably constant b/w different population of the same species as long as similar units and definition are used cm and TL for L∞.
ø' = log10(K) + 2·log10(L∞)
3.15. Distribution
Samples of both species were obtained from different landing centers along the coastal belt of Sindh (District, Karachi, Thatta and Badin) for this study, the main regions in which Karachi has about 135 Km long coastal zone (Khan et al. 1996) it includes main landing centers where the majority of fish from the Sindh coast is landed and auctioned are Karachi Fish Harbour, Ibrahim Hyderi, Rehi Goth (Korangi) and Thatta region includes main fish market Thatta, Gharo, Boharo,Gahro,Keti Bander, Janji Ser, Khharo chhan, Zero point, Tidal link and fish markets of Badin District. Collections were made from five different sites of Korangi Phitti Creek System (Gangyaro creek, Khhuddi creek, Khai khhuddi, Phitti creek and main channel of Ibrahim Haydri) for field survey and collection, by using a 32 feet long fishing boat with the help of gill net and trawl net have mesh size of 1 cm to 2.5cm were used at 15 to 30 feet depth.
3.16. Experimental Design
About 75 samples trip were done during three years (2005-2007) in which 36 trips was from creek area by boat collection and 39 from markets, 40 to 45 specimens were collected randomly in each month collection (1474 specimens of L lutjanus) and (1475 specimens of L johnii) during fortnight trip for boat collection and market during study period (2005-2007) placed in ice filled polyethylene bags and brought to the laboratory of University of Karachi. Washed with fresh water and kept in frozen until the further studies. The summary of the experimental design are as shown in the study work flow chart of Figure 3.6.
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Data Analysis
Figure. 3.4. Work flow chart of present study Size class Fi SAT Micro soft Excel (linear regression) L S Length-weight Von Bit Growth curve a I p b d “R” statistical software Gangyaro Creek o Estimation of age e e Data collection r and growth Microsoft Excel c a n i t t Phitti Creek m o i Population dynamics parameter e r f Shepherd’s method y i Reproductive Biology Khuddi Creek n c Study of growth Powell- Wetherall plot ’ a a s t t Gulland & Holt plot Khai Khuddi Creek ELEFAN U i o Munro’s Method c n Gonads collections Analysis of growth i n Faben’s Method Ibrahim Hiadry o ncrement data v l e a Macroscopic examination Mortality (Z) Length converted catch curve r n l D Jones & Van Zalinge plot Boat collections s d e i i Natural mortality (M) c Beverton and Holt model t M s Data collection y t e s Ault & Ehrardt Method Market collections i o a e Pauly’s Empirical Equation o f s c Otolith collections Rikhter & Efanov’s Method n u K r t Karachi Fish Harbor s Gonad somatic Index Recruitment patterns a e i Macroscopic examination r m o through section cutting a e n Probabilities of capture Ibrahim Hiadry c n h Virtual population analysis i t Data collection L50% maturity Rehri Village Yield per recruitment
RESULTS 90 length estimation(Lmax) Fecundity Growth performance indices
4. Results
Lutjanus lutjanus (Bloch 1790) (Figure 4.1)
English name: Big eye Snapper Local Names: Hiro, Hira Maximum length (TL) 35 cm Conmen length: 27 cm Maximum weight (gm) Common weight 350 gm
Synonymous of Lutjanus lutjanus
Lutjanus lutjanus, Lutjanus lineolatus, Lutjanus balochi, Diacope lineolata, Mesoprion erythognathus, mesoprion xanthopterygius, Rhomboplibide caroui.
Distinguish and Morphometric Characters
Lutjanus lutjanus is known as Big Eye Snapper, Body fusiform, slender, and Vonerine patch triangular with medial posterior, Pre-orbital bone very narrow, much less then eye diameter. Pre opercula notch and knob poorly developed, scale row on back rising
115 obliquely above lateral line. Generally silvery white with a broad yellow strip running along the side from the eye to the caudal fin base. A series of yellow horizontal line is on lower half of the body, fins are pale yellow to whitish, Caught by bottom trawler, normally reef associated found up to 96 meter depth at 32 N-26 S,31 E- 165 in tropical waters, widely distributed at Indo West pacific, East Africa to Solomon Island, North to Southern Japan , South to Australia, frequently encountered in large schools with other Lutjanus sp, soft bottom, sand and in habitat having special features as bed, sea grass and coral reefs at Feed on fishes, maximum age is 11 years and crustaceans recorded from Pakistan 20cm to 30cm, Iwatsuki, (1993) and FAO, (2002). Figure 4.1 Habitat: Lutajnus lutjanus (Big eye snapper) are offshore coral reef fish inhabit and trawling grounds, trawled to depth of almost 100m, (Kuiter,2001) frequently encounter in large schools with other Lutjanus species, these are feeds upon small fishes and crustacean( Sommer,1996).
Distribution: Size frequency distribution data were plotted from pooled data of L. lutjanus caught during three years (2005-2007), from local fish market as well as creek areas of Karachi (Korangi Creek) on monthly basis. Figure 4.2
4.1 Size Frequency Distribution
4.1.1. Year 2005
During the year (2005) 495 specimens of Lutjanus lutjanus were studied randomly from markets and boat collections, about 40 to 45 specimens were collected in every month (201, male, 215, female and 103 were found juvenile or unsex), where the minimum size of specimen at 8 cm (TL) with 25 gm were collected during the month of June, July and August only but in other months its ranging from 10 cm (TL) to 27.9 (TL) with 40 gm to 300 gm (TW).Monthly analysis of size class shown the maximum size of specimen were found in the month of June , July , August and September at 27.5 to 27.9 cm (TL) at Graphs. 4.1 to 4.12 and graphs regarding size class distribution were plotted from pooled data.
4.1.2. Year 2006
During the year (2006) 487 specimens of Lutjanus lutjanus were collected randomly from fish markets and boat collection where 40 to 45 specimens were collected during the month (200 were male,112 female and 175 were found juvenile or unsexed) the
116 minimum size of specimen at 8.5cm (TL) with 25-28 gm were collected during the month of June, July, August and September only but in other months its ranging from 10cm (TL) to 27.5cm (TL) with 40gm to 305gm (TW) histogram regarding size class distribution were plotted from pooled data Graphs. 4.13 to 4.24.
4.1.3. Year 2007
During the year (2007) 492 specimens of Lutjanus lutjanus were collected randomly on monthly basis from fish market and boat collections (172 were male,110 female and 210 were found juvenile or unsex) the minimum size of specimen at 8 cm(TL) with 25 gm were collected during the month of June, July and August only but in other months its ranging from 10 cm (TL) to 27.9 (TL) with 40 gm to 300 gm (TW). Monthly analysis of size class shown the maximum size of specimen were found in the month of June , July , August and September at 27.5 to 27.9 cm (TL) 4.3, graphs 4.25 to 4.36, the size frequency distribution of Lutjanus lutjanus were observed by sex on yearly basis and generated plots shown at Graphs. 4.37- 39.
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Graph 4.1 Graph 4.2
Graph 4.3 Graph 4.4
Graph 4.5 Graph 4.6
Graph 4.7 Graph 4.8
Graph 4.9 Graph 4.10
Graph. 4.11 Graph. 4.12
Graphs 4.1- 4.12 Size frequency distribution of L. lutjanus 2005.
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Graph 4.13 Graph 4.14
Graph 4.15 Graph 4.16
Graph 4.17 Graph 4.18
Graph 4.19 Graph 4.20
Graph 4.21 Graph 4.22
Graph 4.23 Graph 4.24
Graphs 4.13 – 4.24. Size frequency distribution of L. lutjanus 2006.
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Graph 4.25 Graph 4.26
Graph 4.27 Graph 4.28
Graph 4.29 Graph 4.30
Graph 4.31 Graph 4.32
Graph 4.33 Graph 4.34
Graph 4.35 Graph 4.36
Graphs 4.25 - 4.36. Size frequency distribution of L. lutjanus 2007.
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Graph 4.37. Total No’s of specimens of Lutjanus lutjanus studied during Three years (2005-2007).
Graph 4.38. Total No’s of specimens of L. lutjanus studied during 2005
Graph 4.39. Total No’s of specimens of L. lutjanus studied during 2006.
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A
B
C
D
Figure. 4.2. Size distribution of Lutjanus lutjanus collected from Karachi Fish Harbor (Dec 2007), A-27 cm,B-17.2 cm,C-15.2 cm and D-12 cm TL.
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4.2. Analysis of Gonads
4.2.1. Macroscopic and Histological examination of gonads
The Gonads of Lutjanus lutjanus observed visually first and then histologically as shown in table 3.1 and 3.2 the gonads of smaller size class < 4cm to < 9cm TL posses thin, thread like transparent gonads (Figure-4.3-). The gonads of <14cm TL class has large size gonads as compared to smaller size class and contain connective tissues with early germ cell. Distinguishable tissues of testicular material and ovarian were observed first in individuals of <14 cm TL. In immature stage, testicular zone contained spermatogonia and early stage of spermatogenesis while ovarian zone contained previtellogenic stage acolytes in female. The fish of size class < 17.5 to < 21 cm TL are predominated during spawning period contained different stages of spermatogenesis, spermatides, spermatocytes and spermatozoa) and females contained developing stage oocytes. During the spawning season male specimens were dominant in smaller size class rather than the largest class with the milky testicular structure with blood capillaries, female specimens were observed during the spawning season at 12 cm TL to 20 cm TL and fully matured at 27 cm TL, and during the non spawning season such male at 9cm TL to 15cm TL as immature in slightly larger in size with connective tissue, brown bodies, without spermatogenesis. In female specimens during the spawning period ovarian testicular zone contain developing oocytes such as preinuleolar, yolk granules and previtellogenic stages was observed were functional and fully matured in large size at 27cm TL, contained mature yolk granule stage oocytes and vitellogenic oocytes, Figure. 4.3 and 4.4 to 4.9.
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(I )TL= 9 cm (II) TL= 13 cm (III) TL=18cm (IV) TL=23cm
(V) TL= 20.5 cm (VI) TL=25 cm (VII) TL=27cm (VIII)27.5 cm TL
Figure. 4.3 Macroscopic observation of gonads showing different maturity stages in Lutjanus lutjanus (Stage-I to VIII).
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A
B
Figure 4.4 (A) Histological section of Juvenile gonad of 7.5cm Lutjanus lutjanus shows granulocytes (Gc) with stroma cells (S). (B) Histological section of immature ovary of Lutjanus lutjanus shows ovarian lamella (OL) and Previtelogenic acolytes (PVO). Scale bare is 100 µm.
125
Figure 4.5 Histological section of developing ovary of Lutjanus lutjanus shows primary growth and oocytes (PGO) cortical alveolar oocyte (CAO). Scale bare is 100 µm.
Figure. 4.6 Histological section of Lutjanus lutjanus nearly spent ovary contains postovulatory follicles (POF) and late vitellogenic oocytes (VO) scale bare is 50 µm
126
Figure 4.7 Histological section of Late vitellogenic oocyte (LVO) and hydrated oocytes (Hy) of mature female of Lutjanus lutjanus 26.4 cm TL. Scale bars are 100 µm
Figure. 4.8 Photomicrographs of histological section of testis of L. lutjanus mature male shows spermatogonia (SG), spermatides (St), spermatocytes (Sc) and spermatozoa (Sp). Scale bare is 100 µm.
127
A
B
Figure 4.9 (A) Functional male caught during peak season showed different stages of different stages of spermatogenesis Spermatocytes (Sc), spermatids (St) and spermatozoa (Sp). Scale bars E= 100 µm, F= 50 µm. (B) Photomicrographs of histological section of testis of Lutjanus lutjanus maturing male show spermatogonia (SG) and spermatocytes (Sc). Scale bare is 200 µm.
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4.2.2. Monthly variation in maturity stages of Lutjanus lutjanus
Female L. lutjanus were observed during the months of June and July with stage III first, frequency of mature female were observed in October rises up to November and December, where gonads of many females reached at fully mature stages VI and VII.
Few female with were studied and Fully matured females with stages VI and VII were observed in the months of January and February, and mostly spent observed in March as well as in the months of April and May immature/ stages I & II were observed.
In the month of March few females with opaque yolk granules oocytes and post ovulatory follicles (POF) were found trend of gonadal maturity and spent ovaries in dark brown color were observed in November. The values of GSI shown Lutjanus lutjanus spawned in winter to early spring. Graphs.4.40 - 4.75.
The trend of maturity and GSI values shows that L. lutjanus spawned in winter to early spring.
129
Graph 4.40 Graph 4.41
Graph 4.42 Graph 4.43
Graph 4.44 Graph 4.45
Graph 4.46 Graph 4.47
Graph 4.48 Graph 4.49
Graph 4.50 Graph 4.51
Graphs 4.40 – 4.51. Percentage frequency distribution for gonadal maturity stages of Lutjanus lutjanus observed during the year 2005. 130
Graph 4.52 Graph 4.53
Graph 4.54 Graph 4.55
Graph 4.56 Graph 4.57
Graph 4.58 Graph 4.59
Graph 4.60 Graph 4.61
Graph 4.62 Graph 4.63
Graph.4.52 – 4.63. Percentage frequency distribution for gonadal maturity stages of Lutjanus lutjanus observed during the year 2006.
131
Graph 4.64 Graph 4.70
Graph 4.65 Graph 4.71
Graph 4.66 Graph 4.72
Graph 4.67 Graph 4.73
Graph 4.68 Graph 4.74
Graph 4.69 Graph 4.75
Graphs. 4.64 – 4.75. Percentage frequency distribution for gonadal maturity stages of Lutjanus lutjanus observed during the year 2007.
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4.3. Marginal increments Analysis (MIA)
The mean values of marginal increments were plotted against months. The plots showed that the value of mean monthly increments was starting to rise in the month of October to March and peak observed in November- December when maximum value of MI was (0.9 mm) was measured and decline was observed from April to July. The observed value of MI was 0.05 to 0.9 mm. The rise and decline of mean monthly marginal incremental values verified that the only one opaque growth zone delineated in a year. Graph 4.76
Graph 4.76
Graph. 4.76. Monthly changes in gonad somatic index (GSI+) and oocyte composition of Lutjanus lutjanus.
4.4. Estimation of L 50% Sexual maturity
Logistic curve was used for determination of size at 50% maturity by logistic curve by non linear regression analysis. The separate data of males and females used to generate the plots. About 50 mature specimens of both sexes with size class were selected for determination of first maturity the data were used for logistic curve.
The results shown male specimens of Lutjanus Lutjanus attained L50 % maturity at 14 cm TL earlier then female where female attained at L50% maturity 20cm TL. The logistic curve for both sex shows best fit to proportional for male and female the coefficient of correlation shown strong correlation between total length (cm) and sexual maturity. Graph 4.77- 4.78.
133
Graph 4.77
Graph 4.77 Size at 50 % maturity of male specimens of Lutjanus lutjanus.
Graph 4.78
Graph 4.78 Size at 50 % maturity of female specimens of Lutjanus lutjanus.
134
4.5. Oocytes size frequency distribution of Lutjanus lutjanus during three years (2005-07)
The oocytes diameter distribution showed the length of spawning season of fish and frequency distribution of oocyte in fully mature ovaries shows type of fecundity. Fully mature females (Stage-VI) for measurement of oocyte diameter during peak spawning season. Three females were obtained during 2005, 2006 and 2007. The observation of ovarian developmental stages described that Lutjanus lutjanus is a multiple spawned, the hydrated oocytes visible through the ovarian wall and the various developing and maturing oocyte were shown in histological examination. The oocyte size frequency analysis in 10 cm TL female contained smallest oocyte i.e. 0.042 – 0.140 mm in size, which were chromatin nuclear stage oocyte which were skewed towards the left side. The 20 cm TL female was obtained at the peak spawning season showed the same trend the set of small size oocyte was skewed towards the left side. In both the ovaries large set of oocyte i.e. 0.48 – 0.7 mm were skewed towards the right side. The ovaries of 24 cm TL and 27.5 cm TL females were obtained in 2006 and 2007.The large size set of oocyte consist of predominantly on yolk granules and advance hydration stage oocyte. The size difference found in oocyte of Lutjanus lutjanus strongly favors this concept that the Lutjanids is a multiple spawner Graph.4.79 – 4.84.
Graph 4.79
135
Graph 4.80
Graph 4.81
Graph 4.82
136
Graph 4.83
Graph 4.84
Oocytes diameters (mm)
Graphs 4.79–4.84 Oocytes size frequency distribution of Lutjanus lutjanus (stage-V) ripe females 18.5 cm to 27.5 cm, during the three year (2005-2007)
4.6. Fecundity
The fecundity of smallest specimen was observed in L. lutjanus 12 cm TL in length and 340 gm weight was calculated to have 143,264 eggs, and the largest fish of 27 cm in length has 1,768,468 eggs respectively. Fecundity and calculations of Lutjanus lutjanus shows a strong relationship with the length of the fish. The smaller size fish produced a less number of eggs and large size fish produced more number of eggs during the study it is observed that the fecundity increases with increases in size. The mean fecundity of
137
45 specimens of Lutjanus lutjanus is calculated to be 938,888 ± 150,440. In relationship of fish length (TL cm) and No’s of ova through regression analysis all observations of the coefficient of co relation shows positive trend and the slop (b) value is significant from the theoretical slop of 3.0. Graphs.4.85-4.87 and relationship between fish weight (in gm) and No’ of ova were also observed. For fecundity of Lutjanus lutjanus five mature females (stages V-VI) for the determination of the relationship between fecundity and total length and weight. The relationships observed by log linear regression. The natural logarithms of fecundity, total length and weight values are taking and relationships described. Graphs 4.85- 4.90.
Log W=b +a log L = n=
Where:
F = Fecundity
W =Total weight of fish b = log length of fish (TL) a = counted eggs
L = length of fish
= correlation coefficient
After getting plot of length Vs fecundity by computer program excel following results were obtained.
2005 Log F= 19855 + -20175 ( = 0.847)
2006 Log F=10200 + -18789 ( = 0. 833)
2007 Log F=18995 + -18272 ( =0.842)
138
Graph 4.85
Graph 4.86
Graph 4.87
Graph 4.85 – 4.87 Relationship between annually potential fecundity with length (TL cm) of Lutjanus lutjanus during 2005-2007.
139
Regression analysis between fish Weight and Fecundity.
2005 Log F = 1252 log W + - 6222 ( 0.985)
2006 Log F = 1127 log W + -33820 ( 0.824 )
2007 Log F = 1203 log W + -45441 ( 0.827)
Graph 4.88
F e c u n d i t y
Fish wight gm
Graph 4.89
F e c u n d i t y
Fish wight gm gggggmgm
140
Graph 4.90
Graph 4.88 -4.90. Relationship between annually potential fecundity with somatic wt gm of Lutjanus lutjanus during 2005-2007
4.7. Percentage frequency distribution of Lutjanus lutjanus (male, female and juvenile)
Length frequency distribution data of gonadal maturity was used to generate the plot from Microsoft excel program which shows the smaller size class from < 3 cm TL to 13 cm TL were dominated as immature individuals. Immature males shown in gray color were first time observed in <11 cm TL size class and dominated the 18 cm to 20 cm TL size class and mature males shown in blank with white colored vertical lines were observed first time in < 11 cm size class Female shown black, white and brown color first time observed at <11 cm TL and dominant at 18 cm TL to 20 cm TL. The size < 24 cm to 27 cm has three types of individuals including mature males, and immature specimens. Graph 4.91.
Graph 4.91
Graph. 4.91. Percentage frequency distribution of Lutjanus lutjanus during the year 2005-2007.
141
4.8. Length weight relationship
In the present study, the determining values of slopes by regression of combine data shows found no significant difference between the theoretical slop of 3. The length weight relationship of Lutjanus lutjanus determined by the logarithmic transformation, from pooled data of 2005 to 2007, statistical values of the regression analysis shown in the table: 4.1. The relationship equations of combined data of log length and log weight calculated yearly basis, shown no significant differences and the values of the coefficient of correlation (r²) were highly significant. The equations of linear regression data obtained from three (2005 – 2007) years. Graphs. 4.92-4.94.
Overall (male, Regression Log W = Log a + b Log L r2 P – Value female and unsexed
2005 (N=475) Log10 Weight = Log10 (-0.641) + 2.123Log10 0.922 0.000
2006 (N=428) Log10 Weight = Log10 (-0.549) + 2.045Log10 0.922 0.000
2007 (N=483) Log10 Weight = Log10 (-0.545) + 2.046Log10 0.936 0.000
Table. 4.1 values of length weight relationship of Lutjanus lutjanus during three years
Graph 4.92
142
Graph 4.93
Graph 4.94
Graph.4.92–4.94 Length weight relationship of Lutjanus lutjanus during three years (2005- 2007).
143
4.9. Linear regression analysis
For further estimation of correlation between following relationships the linear regression graphs on monthly basis from pool data were plotted with the help of equation is “Y=b X and ” between following:-
Fish weight(gm) VS Fish length (TL)
Fish weight (gm) VS Otolith weight (gm)
Fish length (cm) VS Otolith size (mm)
Fish length (cm) VS Scale size (mm)
Where:-
Y= Fish weight and X = TL
Y=Fish weight and X= OW (Otolith weight)
Y= Fish length and X = OS (Otolith size)
Y= Fish length and X = SS (Scale size
The results of linear regression analysis of all above correlations shows strong significant values and no difference observed between theoretical slope with strong correlations, the coefficient of correlation r2 was higher in September and December (2005), in August, September and October (2006) and August, September and December (2007), further month wise relationship between Fish length (TL cm) Vs fish weight (gm), fish length Vs scale size, fish length Vs otolith size (mm) fish weight gm Vs otolith weigh (mg) by regression analysis shown at Graphs 4.95 to 4.252.
144
Graph 4.95 Graph 4.96
Graph 4.97 Graph 4.98
Graph 4.99 Graph 4.100
Graph 4.101 Graph 4.102
Graph 4.103 Graph 4.104
Graph 4.105 Graph 4.106
Graphs 4.95 – 4.106. Regression analysis between Fish wt (gm) VS Fish length (TL) of Lutjanus lutjanus during 2005.
145
Graph 4.107 Graph 4.108
Graph 4.109 Graph 4.110
Graph 4.111 Graph 4.112
Graph 4.113 Graph 4.114
Graph 4.115 Graph 4.116
Graph 4.117 Graph 4.118
Graphs 4.107 – 4.118.Regression analysis fish length (TL) vs Scale size (mm) of L. lutjanus from January 2005 to December 2005.
146
Graph 4.119 Graph 4.120
Graph 4.121 Graph 4.122
Graph 4.123 Graph 4.124
Graph 4.125 Graph 4.126
Graph 4.127 Graph 4.128
Graph 4.129 Graph 4.130
Graphs 4.119 – 4.130. Regression analysis between Fish length (cm) vs Otolith size (mm) of L. lutjanus during January to December 2005.
147
Graph 4.131 Graph 4.132
Graph 4.133 Graph 4.134
Graph 4.135 Graph 4.136
Graph 4.137 Graph 4.138
Graph 4.139 Graph 4.140
Graph 4.141 Graph 4.142
Graphs 4.131 – 4.142. Regression analysis between Fish wt (gm) vs Otolith wt (OT) of L. lutjanus from January 2005 to December 2005.
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Graph 4.143 Graph 4.144
Graph 4.145 Graph 4.146
Graph 4.147 Graph 4.148
Graph 4.149 Graph 4.150
Graph 4.151 Graph 4.152
Graph 4.153 Graph 4.154
Graphs 4.143 – 4.154. Regression analysis between Fish wt (gm) Vs Fish length (TL) of L. lutjanus during January to December 2006.
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Graph 4.155 Graph 4.156
Graph 4.157 Graph 4.158
Graph 4.159 Graph 4.160
Graph 4.161 Graph 4.162
Graph 4.163 Graph 4.164
Graph 4.165 Graph 4.166
Graphs 4.155 – 4.166. Regression analysis fish length (TL) Vs Scale size of L. lutjanus from January to December 2006.
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Graph 4.167 Graph 4.168
Graph 4.169 Graph 4.170
Graph 4.171 Graph 4.172
Graph 4.173 Graph 4.174
Graph 4.175 Graph 4.176
Graph 4.177 Graph 4.178
Graphs 4.167 – 4.178. Regression analysis between Fish length (cm) VS Otolith size (mm) of Lutjanus lutjanus from January to December 2006.
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Graph 4.179 Graph 4.180
Graph 4.181 Graph 4.182
Graph 4.183 Graph 4.184
Graph 4.185 Graph 4.186
Graph 4.187 Graph 4.188
Graph 4.189 Graph 4.190
Graphs 4.179 – 4.190. Regression analysis between Fish wt (gm) VS Otolith wt (OT) of Lutjanus lutjanus from January to December 2006.
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Graph 4.191 Graph 4.192
Graph 4.193 Graph 4.194
Graph 4.195 Graph 4.196
Graph 4.197 Graph 4.198
Graph 4.199 Graph 4.200
Graph 4.201 Graph 4.202
Graphs 4.191 – 4.202. Regression analysis between Fish Length (cm) VS Fish wt (gm) of Lutjanus lutjanus January to December 2007.
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Graph 4.203 Graph 4.204
Graph 4.205 Graph 4.206
Graph 4. 207 Graph 4.208
Graph 4.209 Graph 4.210
Graph 4.211 Graph 4.212
Graph 4.213 Graph 4.214
Graphs 4.203 – 4.214. Regression analysis between Fish Length (cm) VS Fish wt (gm) of Lutjanus lutjanus January to December 2007.
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Graph 4.215 Graph 4.216
Graph 4.217 Graph 4.218
Graph 4.219 Graph 4.220
Graph 4.221 Graph 4.222
Graph 4.223 Graph 4.224
Graph 4.225 Graph 4.226
Graphs 4.215 – 4.226. Regression analysis fish length (TL cm) v s Scale size(mm) of L. lutjanus January to December 2007.
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Graph 4.227 Graph 4.228
Graph 4.229 Graph 4.230
Graph 4.231 Graph 4.232
Graph 4.233 Graph 4.234
Graph 4.235 Graph 4.236
Graph 4.237 Graph 4.238
Graphs 4.227 – 4.238. Regression analysis between Fish length (TLcm) VS Otolith size (mm) of Lutjanus lutjanus January to December 2007.
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Graph 4.239 Graph 4.240
Graph 4.241 Graph 4.242
Graph 4.243 Graph 4.244
Graph 4.245 Graph 4.246
Graph 4.247 Graph 4.248
Graph 4.249 Graph 4.250
Graphs 4.239 – 4.250. Regression analysis between Fish wt (gm) Vs Otolith wt (OT) of Lutjanus lutjanus January to December 2007. 157
4.9.1 Fish Length TL (cm) Vs Fish weight (gm)
Donated and pronounced R squared indicates how well data points fit a line or curve. In present study during the year 2005, 2006 and 2007 for linear regression analysis for fish length (TL) cm V/s fish weight (gm) shows strong correlations.
4.9.2 Fish Length TL (cm) V/s Scale Size (mm)
Donated and pronounced R squared indicates how well data points fit a line or curve. In present study during the year 2005, 2006 and 2007 for linear regression analysis for fish length (TL) cm V/s Scale size mm shows strong correlations
4.10. Estimation of age and growth
4.10.1. Otolith Morphology
The Sagittal otolith is whitish to translucent and rhomboidal in shape with moderate thickness. Margins are wavy, laterally compressed and distal surface is slightly concave, laterally compressed at distal surface. Figure.4.10 - 4.12.
8 cm TL
Figure. 4.10. Whole otolith of Lutjanus lutjanus Juvenile scale bar is 2 mm.
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14 cm TL
Figure 4.11. Whole otolith of Lutjanus lutjanus three years old. Scale bar is 2 mm
19.5 cm TL
Figure 4.12. Whole otolith of L. lutjanus 5 year old individual. Scale bar is 2 mm.
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4.10.2. Scales observations Body covered with ctenoid type of scales at posterior end with small teeth as projections ctenii, around focus area of scale, growth zones circulies arranged. in present study observed that the scales of smaller size class shown more circulies rather than the older. Figure. 4.13.
4.10.3 Sectioned otolith Vs whole otolith
In juveniles and small age individuals of lutjanus lutjanus the opaque growth zones were easily observed on whole otoliths rather than older age specimens therefore the fish grow then the otolith turned to opaque and growth zones were difficult to study, as well as through sectioned otolith opaque growth zones were easy to study as compared to whole otolith. The otolith of Lutjanus lutjanus was whitish to translucent in color and rhomboidal in shape with moderate thickness with wavy margins, laterally compressed and distal surface is slightly concave.
4.10.4. Otoliths Vs Scales
Otolith and scales were compared for estimation of age. Both hard parts have growth zones at the same time but the scale circuli was in greater numbers and showed no sequence of growth rings as compared to the otolith of same individual and zones were increased as fish age increased.
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I IV
II V
III VI
Figure 4.13. Magnified photographs of Lutjanus lutjanus scales show different numbers of growth zones. i: 9.5 cm TL, ii: 17cm TL, iii: 20cm TL, vi: 22.5cm TL, v: 24cm TL and 27cm TL. Scale bar in all is equal to 2 mm.
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4.11. Age estimation of Lutjanus lutjanus
Age and growth was estimated by the whole otolith of both species .i.e. Lutjanus lutjanus as refer by Andrade, 2003 as well as count numbers of opaque zones from sectioned otolith with the help of stereomicroscope attached with digital camera and images of sectioned otolith were analyzed with the help of image J software and radius of each section was measured at fixed scale growth rings were estimated by whole otolith and selected were sectioned there are the younger one have 0.5 years at 9cm TL and oldest were 9 years old at 27 cm TL. Figure 4.14 and 4.15. R:1
9.5cm TL
R: 2
15.5cm TL
R:3 18.5cm TL
Figure 4.14 Transverse sections of otolith of Lutjanus lutjanus, black dots shows different opaque growth zones, scale bar is 2mm.
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R:4 19 cm TL
R:5 24.5 cm TL
R:6 27.5 cm TL
Figure 4.15. Transverse section of otolith of Lutjanus lutjanus black dots shows different opaque growth zones, scale bar is 2mm.
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4.12. Determination of growth of Lutjanus lutjanus
The sectioned otolith based length–at-age data of Lutjanus lutjanus were used for determination the growth curve through software’s, data was fitted to von Bertalanffy growth model for males, females and overall individuals.
The model fitted with the all data sets, curve of growth model reduced beyond the + 8 age cohorts. The length at-age data of both sexes showed difference between males and females. The maximum observed age from sectioned otolith was 11 years. The von Bertalanffy plot curve demonstrates that the age of 1 year to 5 years had an average, from 8 years to 11 years attained the length of 26cm to 27.5cm TL for L. lutjanus.
4.12.1. Method for fitting von Bertalanffy growth parameters by linear regression analysis (Constantine Stamatppoulos and Caddy (1987; Constantine Stamatppoulos, 2005)
Observations of growth rings at whole otolith were used to determine the age and growth by length at age data of L. lutjanus in present study sectioned otolith based length at age data was used to determine the growth of Lutjanus lutjanus, maximum observed age was 9 years. The growth parameters of Von Bertalanffy equation L∞, t0 estimated by using VONBIT software (Stamatppoulos, C. 1989).The Data was fitted to the von Bertalanffy growth model for male, female and overall (mixed), observed difference between the age at length and estimated age by growth equation parameters, and for further estimation the whole data of three years was fitted to software and obtained plots. The values were obtained by above plots, Tables 4.2 -4.5.
The Von Bertalanffy growth function (VBGF) demonstrates that the age at 1 year to 5 year shown an average but from 6 year to 9 years attained the length of 20 cm TL to 27 cm TL. The coefficient of correlation of males, females and all individuals (mixed) shown good correlation. graphs graphs,251-253 (male),254-256 (female) and 257-259 (all individuals) on yearly basis and for three years (2005-07),4.261 (male) 4.262, (female) and 4.263, (all individuals).
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Graph 4.251
Graph 4.252
Graph 4.253
Graphs 4.251 -253. Von Bertalanffy growth function (VBGF) fitted to length age data of Lutjanus lutjanus (male) during three years (2005-2007)
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Graph 4.254
Graph 4.255
Graph 4.256
Graphs 4.254-256 Von Bertalanffy growth function (VBGF) fitted to length age data of Lutjanus lutjanus (Female) during three years (2005-2007).
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Graph 4. 257
Graph 4. 258
Graph 4.259
Graphs 4.257 -259. Von Bertalanffy growth function (VBGF) fitted to length age data of Lutjanus lutjanus (combined) during three years (2005-2007)
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Graph4. 260
Graph 4.261
Graph 4.262
Graphs 4.260- 262. Von Bertalanffy growth function (VBGF) fitted to length age whole data Lutjanus lutjanus during three years (2005-2007).
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Table 4.2. Values of Von Bertalanffy growth curve model plotted for the data of Lutjanus lutjanus (Male) observed during three years (2005-2007). .
Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination of observation freedom L∞ t0 r²
2005 0.147 0.940 850 848 33.206 -2.076 32.880 – 33.531 -3.552 -0.600
2006 0.136 0.955 354 352 34.053 -2.257 33.474 – 34.632 -3.917 -0.598
2007 0.135 0.953 328 326 34.196 -2.255 33.583 – 34.796 -3.918 - 0.592
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Table 4.3.Values of Von Bertalanffy growth curve model plotted for the data of L. lutjanus (Female) observed during three years(2005-2007).
Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination observation freedom L∞ t0 of r²
2005 0.149 0.955 489 487 33.199 -1.928 32.880 – 33.702 -3.928 -0.560
2006 0.147 0.954 463 461 333.382 -1.952 32.855 – 33.900 -3.345 -0.559
2007 0.143 0.953 455 453 33.610 -2.049 33.099 – 34.121 -3.526 - 0.571
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Table 4.4. Values of Von Bertalanffy growth curve model plotted for the data of L. lutjanus (Combined) yearly observed during three years (2005-2007).
Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination observation freedom L∞ t0 of R²
2005 0.116 0.949 850 848 36.433 -2.537 36.047- 36.789 -4.495 -0.579
2006 0.116 0.948 791 789 36.403 -2.539 36.034 – 36.771 -4.499 -0.579
2007 0.112 0.948 749 747 37.022 -2.590 36.642 – 37.402 -4.610 - 0.570
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Table 4.5. Values of Von Bertalanffy growth curve model plotted for three years (Combined) data of L. lutjanus observed during (2005-2007).
Sex Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination of observation freedom R² L∞ t0
Male 0.135 0.962 566 564 34.289 -2.177 33.806- 34.773 -3.779 -0.575
Female 0.139 0.959 613 611 33.954 -2.101 33.479 – 34.419 -3.631 -0.571
All individuals 0.119 0.955 963 981 37.022 -2.426 36.896 – 35.546 -4.284 - 0.568 (unsex, male and female
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4.12.2. Estimation of age and growth by von bit growth equation in “R” statistical Software.
Same data for three years (2005-2007) of Lutjanus lutjanus was used to estimate the age of L. Lutjanus, mean length and observed length by “R” software. Graphs 4.263- 2.265 (male specimens), 4.266 -268 (female specimens) and 4.269-271 (combined data of three years) as used by Lawson, (2006).
Graph 4.263
Graph 4.264
Graph 4.265
Graphs 4.263-265. Von Bertalanffy growth curves fitted to length age data by “R” statistical software of Lutjanus lutjanus (Male)
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Graph 4.266
Graph 4.267
Graph 4.268
Graphs 4.266-268 The Von Bertalanffy growth curves by “R” software fitted to length age data of Lutjanus lutjanus (female) for three years (2005-2007).
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Graph 4.269
Graph 4.270
Graph 4.271
Graphs 4.269-2.271 The Von Bertalanffy growth curve by “R” software fitted to length age data of Lutjanus lutjanus, all individuals (2005-2007)
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4.12.3. Mean length and observed length
For further study data of Lutjanus lutjanus was used for observation of relationship between mean length and observed length and plots were generated by “R” software by sex (male and female), shown at graphs 4.272-74 (male), 4.276- 78 ( female) and values of mean length were observed at Table 4.6 and 4.7. L. lutjanus (Male)
Graph 4.272
Graph 4. 273
Graph 4.274
Graphs 4.272 –274. The mean length and observed length of Lutjanus lutjanus (male) during three years (2005-2007).
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L. lutjanus (Female)
Graph 4.275
Graph 4.276
Graph 4.277
Graphs 4.275 –277. The mean length and observed length of Lutjanus lutjanus Female during three years (2005-2007).
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Age Mean Length Age Mean Length Age Mean Length (years) (cm) (years) (cm) (years) (cm) 2005 N=201 2006 N=200 2007 N=172
0.5 10.3 0.5 10.3 0.5 10.2
1 12.4 1 12.6 1 12.6
1.5 13.4 1.5 13.4 1.5 13.43
2 14.6 2 15.0 2 15.0
2.5 16.0 2.5 16.0 2.5 16.14
3 17.4 3 17.5 3 17.5
3.5 18.6 3.5 18.6 3.5 18.6
4 19.2 4 19.4 4 19.4
4.5 19.4 4.5 19.5 4.5 19.5
5 21.4 5 21.4 5 21.3
5.5 21.9 5.5 21.9 5.5 21.9
6 23.0 6 23.0 6 22.8
6.5 23.0 6.5 23.0 6.5 23.19
7 25.0 7 25.0 7 25.0
7.5 26.3 7.5 26.3 7.5 26.3
8 26.2 8 26.2 8 26.2
8.5 26.5 8.5 26.5 8.5 26.5 9 9 26.0 9 26.0 26.9
Table 4.6. Mean length and observed length values of L. lutjanus (Male) during three years (2005-2007)
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Age Mean Length Age Mean Length Age Mean Length (years) (cm) (years) (cm) (years) (cm) 2005 N=215 2006 N=112 2007 N=110
0.5 7 0.5 7.1 0.5 7.1
1 10.0 1 9.7 1 10.0
1.5 12.5 1.5 12.4 1.5 12.4
2 13.5 2 13.4 2 13.4
2.5 14.6 2.5 14.6 2.5 14.6
3 16.0 3 16.0 3 16.0
3.5 17.3 3.5 17.4 3.5 17.4
4 18.3 4 18.4 4 18.4
4.5 19.0 4.5 19.1 4.5 19.1
5 19.8 5 19.9 5 19.9
5.5 21.6 5.5 21.8 5.5 21.8
6 21.9 6 22.2 6 22.2
6.5 23.0 6.5 23.0 6.5 23.0
7 23.0 7 23.0 7 23.0
7.5 24.8 7.5 24.8 7.5 24.8
8 26.4 8 26.5 8 26.5
8.5 25.9 8.5 26.0 8.5 25.8 9 9 26.5 9 26.5 26.5
Table 4.7. Mean length and observed length values of L. lutjanus (Female) during three years (2005-2007)
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4.13. Estimation of Population dynamics (FiSAT-II 1.2.2 VER FAO, ICLARM). In present study, we observed wide range of size class of L. lutjanus during the months of year. The size frequency data from January 2005 to December 2007 used as input in FiSAT-II and different population parameters of Lutjanus lutjanus to
estimate the parameters (e.g., L¥, K, C, M, Z, etc.) and predict yield or stock-related attributes given certain fishing scenarios, all individuals (unsex, male and female) population on yearly basis
Figure 4.16. Length frequency and fitted Von Bertalanffy growth curve of L. lutjanus (all individuals) 2005
4.13.1. Estimation of population dynamics parameters for L. lutjanus (all individuals) 2005
4.13.1.1. ELEFAN 1
In this study we observed the length frequency data of L. lutjanus was varied 2.0 cm to 27cm TL The asymptotic length (L∞) and growth parameter (K) was calculated by ELEFAN I program by using Von bertallanfy growth function and values of L∞ 24.68, K 0.540 and score 0.212 were obtained by ELEFAN -1, through length frequency data of Lutjanus lutjanus (all individuals) 2005. Figure 4.17.
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The Length frequency data were analyzed by using the FAO ICLARM FiSAT software and values of L∞ 26.66, K 0.542 per year respectively. Figure 4.18.
4.13.1.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value .i.e.0.560, on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of L∞ 39.36 and K 0.361, Figure 18.
Figure 4.17. Estimation of K for A. Figure 4.18 Estimation of K by emploing intermedius by emploing ELEFAN-1 of Shepherd’s method for L. lutjanus (all L.lutjanus (all individuals) 2005. individuals) 2005.
4.13.1.3. Powell-Wetherall plot
Steady state population of L. lutjanus estimated through this method and values of L and Z/k were stimulated through a sample representing a steady state population by pooling a time series of length frequency data with constant size class, Figure 4.19.
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Figure 4.19. Powell –Wetherall plot for L. lutjanus (all individuals) 2005
4.13.1.4. Analysis of Growth Increment of Lutjanus lutjanus (all individuals) 2005.
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data.
4.13.1.4.1 Gulland and Holt plot
Preliminary growth parameters were estimated by growth increment data of L. lutjanus , which based under VBGF growth rate decline linearly with length reached zero at and residuals of plot were used for inferences on seasonality of growth, in present study the values of L∞ ,24.68 and K 1.068 were estimated, Figure 4.20.
Figure 4.20. Gulland and Holt Plot. For L. Figure 4.21 Munro’s plot based on lutjanus (all individuals) 2005 (Munro 1982) L. lutjanus (all individuals) 2005
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4.13.1.4.2. Munro’s plot
Munro’s plot is based on Munro (1982) used for estimation of growth parameters for L. lutjanus (all individuals) 2005, values of L∞ 24.68 and K, 1.208 were obtained, (Figure 4.21).
4.13.1.5. Mortality estimation
For estimation of Mortality rates several programs were used for estimation, in present study FiSAT - II such as total mortality (Z) from steady state sample and length converted catch curve and natural mortality (M) by the steady state population.
4.13.1.5.1. Total mortality (Z)
4.13.1.5.1.1. Length converted catch curve
Total mortality for Lutjanus lutjanus all individuals (unsex , male and female) for the year 2005 and Z/yr was obtained as (Z/yr) 0.52 (C:I-3.56 to 4.60) for Z=D.52;M at (26ºC)=D.55:F=0.03, E0.06, and Length converted catch curve was plotted by length frequency data with constant size class. (Figure 4.22).
4.13.1.5.1.2. Jones / Von Zalinge plot
In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve (Figure 23).
Figure 4.22 Length converted catch curve Figure 4.23 Length converted catch for L .lutjanus (all individuals) 2005, curve for L .lutjanus (all individuals) darkened full dots represent the points 2005, for estimation of total mortality used in calculating through least square (Z) linear regression and the open dots represent the points either not fully recruited.
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4.13.1.5.3 Total mortality (Z) from mean length
4.13.1. 5.3.1 Beverton and Holt model (1956)
For this study for the data of L .lutjanus (all individuals) 2005 used for estimation of total mortality (Z) through Beverton and Holt plot and obtained the value of Z: 0.014/year , it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that L is estimated from steady state population data of size frequency.
4.13.1.5.3.2 Ault and Erhardt method
This method is used for short live life span tropical species , therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally Z for Lutjanus (all individuals) 2005 was 0.015/year .
4.13.1.5.4 Natural mortality (M)
In FiSAT II for estimation of natural mortality (M) two empirical and one analytical models were used.
4.13.1.5.4.1. Rikhter and Efanove’s method
In present study this model was used to estimate the natural mortality (M) was 0.110/year, to age at which 50% of the stock reaches the age of “ massive spawning”
(tmass).
4.13.1.5.4.2. Pauly’s Equation
Natural mortality estimated by Pauly’s was 0.216/year .It were derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ is available after the L∞ (cm), K (year•¹ ) and temperature (mean annual habitat temperature , 26ºC).
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4.13.1.6. Recruitment pattern
In present analysis the recruitment pattern was uni modal (Figure 4.24) plot was generated by length frequency data of Lutjanus lutjanus (all individuals) 2005, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class.
Figure. 4.24. Recruitment pattern of Lutjanus lutjanus (all individuals) 2005.
4.13.1.7. Probabilities of Capture
The probability of capture of L. lutjanus was estimated through length frequency data of Lutjanus lutjanus (all individuals) 2005 the type of gill net is discussed and curve was obtained. The gill net selection curves were characterized by strong left hand and right hand by normal curves, the different probabilities at length size of 25% (L25 was
2.67 cm and L50 3.62cm and L75 5.33cm) the obtained values showed the high catching probability of the small sized individuals by gill net fishing. (Figure. 4.25).
4.13.1.8. Virtual Population analysis
Results obtained through analysis showed the minimum fishing mortality occurs and highest rates of survival in juveniles and smaller size class individuals, estimated from length frequency data of total catch L. lutjanus (all individuals) during the year of 2005 plot of virtual population to analyzed the population structure was generated Figure. 4.26.
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Figure. 4.25 Probability of capture of L. Figure. 4.26. Length based virtual population lutjanus (combined) 2005 by gill net analysis L. lutjanus (combined) 2005.
4.13.1.9. Relative Yield – Per Recruit and Biomass per Recruit
Knife –edge selection Relative Y/R and B/R of FiSAT –II was used to determine the yield per recruit and biomass per recruit, which calculated the E10= 0.419, E50= 0.321 and Emax: 0.485. The obtaining value of M/K is 0.540. The result showed that the level of E is lower as compared to (Y/R). The maximum sustainable yield (MSY) can be attain with an exploitation rate of 1.0. The present obtaining results indicated that the L. lutjanus is not exploited above the maximum sustainable yield. Figure. 4.27 (A) & (B). Table. 4.8.
Figure. 4.27. (A). Yield isopleths /Recruit analysis (Knife-edge selection) (B). Relative yield-per-recruit and E=1.0 and recruit for L. lutjanus (all individuals) 2005
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Table. 4.8. Relative analysis recruitment analysis results for L. lutjanus for 2005.
4.13.1.10. Maximum length estimation
The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law. Figure-4.28. L* = a+ 1/a. p Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion L max= intercept of regression live with probability
Figure 4.28. Predicted maximum length of L. lutjanus (all individuals) 2005, based on extreme value theory (Formation et al., 1991). The predicted maximum length value and the 95% confidence interval is obtained from intersection of overall maximum length with line b and a, c respectively.
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4.13.2. Estimation of population dynamics parameters for L. lutjanus (all individuals) 2006
In the present study, we observed the wide size range of L. lutjanus in different months of the year. The size frequency data from January 2006 to December 2006 used as input in FiSAT and the different population parameters of L. lutjanus was determined by using the FAO- ICLARM Stock Assessment Tool FiSAT software Gayaniol et al. (1996).Figure-4.29.
Figure 4.29. Length frequency and fitted Von Bertalanffy growth curve. L. lutjanus (whole data) 2006.
4.13.2.1. ELEFAN 1
Through length frequency data of Lutjanus lutjanus, whole data (all individuals) 2006 The asymptotic length (L∞) and growth parameter (K) was calculated by ELEFANI program using Von Bertallanfy Growth Function and growth curve of best fit and values of L∞ 39.38, k 0.380 and score 0.178 were obtained by ELEFAN 1 Figure 4.29 and 4.30.
4.13.2.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of obtained as L39.38 and K 0.530, Figure 4.31. 188
Figure 4.30. Estimation of K for A. Figure 4.31. Estimation of K by emplying intermedius by emplying ELEFAN-1 of L. Shepherd’s method for L.lutjanus (all lutjanus (all individuals) 2006. individuals) 2006.
4.13.2.3. Powell-Wetherall plot
This method used for estimation of values of L and Z/k through a sample representing a steady state population by pooling a time series of length frequency data with constant size class, and obtained the values of cut off length (L; cm) and mean length (L’) Figure 4.32.
Figure 4.32. Powell –Wetherall plot for L. lutjanus (all individuals) 2006.
4.13.2.4. Analysis of Growth Increment of L. lutjanus (all individuals) 2006.
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Growth increment of L. lutjanus estimated by growth increment data and values were obtained as L,39.38, K,0.210.
4.13.2.4.1. Gulland and Holt plot
Gulland and Holt plot was used through preliminary growth parameters and values were estimated by growth increment data and values of L ,24.68 and K 1.068 were obtained based under VBGF growth rate decline linearly with length, reached zero at and residuals of plot were used for inferences on seasonality of growth, in present study plot. Figure 4.33.
Figure 4.33. Gulland and Holt Plot. for L. Figure. 4.34. Munro’s plot based on (Munro lutjanus (all individuals) 2006. 1982) L. lutjanus (all individuals) 2006
4.13.2.4.2. Munro’s plot
Munro’s plot used for values of growth parameters for L. lutjanus (all individuals) 2006, and obtained values as L∞ 39.38 and K, 0.517, Figure 4.34.
4.13.2.4.3. Mortality estimation
For estimation of mortality several programs were used for through FiSAT II such as total mortality (Z) from steady state sample and length converted catch curve, natural mortality (M) through steady state population data.
4.13.2.4.4. Total mortality (Z)
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4.13.2.4.4.1. Length converted catch curve
Length converted catch curve analysis was used to calculate the mortality for L. lutjanus for the year 2006 and values of Z/yr was obtained as (Z/yr) 0.71 (C:I. 0.209 to 0.350) for Z=D.52;M at (26ºC)=D.55:F=0.03, E0.06, and Length converted catch curve was plotted by length frequency data with constant size class, Figure 4.35.
4.13.2.4.4.2. Jones / Von Zalinge plot
In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve, Figure 4.36
Figure 4.35 Length converted catch curve for Figure 4.36 Jones and van Zallinge plot for L. L. lutjanus (all individuals) 2005, darkened lutjanus (all individuals) 2006, for estimation full dots represent the points used in of total mortality (Z) of L. lutjanus (all calculating through least square linear individuals) 2006. regression and the open dots represent the points either not fully recruited.
4.13.2.5. Total mortality (Z) from mean length
4.13.2.5.1. Beverton and Holt model (1956)
In present study the Beverton and Holt plot used to estimate the of Z and obtained value of Z :0.335/year data of L. lutjanus (all individuals) 2006 through ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that L is estimated from steady state population data of size frequency.
4.13.2.5.2. Ault and Erhardt method
191
Through this method life span of L. lutjanus was studied i.e. used for short live life span tropical species, therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally Z for L. lutjanus (whole data) 2006 estimated values was 0.341.
4.13.2.5.3. Natural mortality (M)
In FiSAT II for estimation of natural mortality (M) two empirical and one analytical model were used.
4.13.2.5.3.1. Rikhter and Efanove’s method
In present study this model was used to estimate the natural mortality (M) to age at which 50% of the stock reaches the age of “ massive spawning” (tmass).
4.13.2.5.3.2. Pauly’s Equation
Data of Lutjanus lutjanus was used natural mortality estimated by Pauly’s equation was and estimated values recorded as 1.0544/year , derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ ,K (year•¹) and temperature (mean annual habitat temperature (26ºC).
4.13.2.6. Recruitment pattern
In present analysis the recruitment pattern was unimodal plot for recruitment pattern was generated throgh length frequency data of Lutjanus lutjanus (all individuals) 2006, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class, Figure 4.37.the more or less continuous prolonged recruitment march to November with peak (~18%) in June was observed. The recruit pattern shows the high recruitment occurred in immature stages of growth. Figure. 4.37.
192
Figure 4.37. Recruitment pattern of L. lutjanus (all individuals) 2006.
4.13.2.7. Probabilities of Capture
The probability of capture of L. lutjanus was estimated through Length frequency data of (all individuals) 2006 was used for estimation of probabilities of capture by the gill net option and curve was obtained. Gill net selection curves were characterized by strong left hand and right hand by normal curves, Figure 4.38.
4.13.2.8. Virtual Population analysis
The results obtained through analysis showed that the maximum fishing mortality the plot showed the highest rate of survival in juvenile and smaller size class individuals. It indicated that the population of L. lutjanus is not immediate threat because of overfishing or predation plot was obtained from length frequency data of total catch Lutjanus lutjanus (female) during the year of 2005 was used to generate the plot of virtual population to analyzed the population structure by Jones and Von Zaling method (1981), Figure 4.39.
193
Figure 4.38. Probability of capture of Figure.4.39 Length based virtual L. lutjanus (all individuals) 2006 by population analysis L. lutjanus (all gill net. individuals) 2006.
4.13.2.9. Relative Yield – Per Recruit and Biomass per Recruit
The Knife–edge selection of FiSAT-II was used to determine the yield per recruit Y/R and biomass per unit B/R and Relative-yield-Per- recruit is based upon Beverton and Holt model (1956), obtained values were E10= 0.557, E50= 0.0.412 and Emax: 0.639 and M/K is 0.150. The maximum sustainable yield (MSY) can be attain with an exploitation rate of 1.0. The present obtaining results indicated that the L. lutjanus is not exploited above the maximum sustainable yield. Figure 4.40. (A) and (B).Table 4.9.
Figure 4.40.(A) Yield isopleths /Recruit analysis (Knife-edge selection) (B). Relative yield-per-recruit and E=1.0 and Lo/Lo biomass-per recruit for L. lutjanus (all individuals) 2006
194
Table 4.9. Relative analysis recruitment analysis results 2006.
4.13.2.10. Maximum length estimation
The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law. L* = a+ 1/a. p
Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion L max= intercept of regression live with probability. Figure. 4.41.
Figure 4.41. Predicted maximum length of L. lutjanus (all individuals) 2006, based on extreme value theory (Formation et al., 1991). The predicted maximum length value and the 95% confidence interval is obtained from intersection of overall maximum length with line b and a, c respectively.
195
4.13.3. Estimation of population dynamics parameters for L. lutjanus (all individuals) 2007.
In present study, we observed wide range of size class of L.lutjanus during the months of year. The size frequency data from January 2005 to December 2007 used as input in FiSAT II and different population parameters of L.lutjanus to estimate the parameters (e.g., L¥, K, C, M, Z, etc.) and predict yield or stock-related attributes
Figure 4.42. L. lutajanus, length frequency and fitted Von Bertalanffy growth curve.(all individuals) 2007 given certain fishing scenarios, all individuals (unsex, male and female) population on yearly basis and whole during the year (2007). Figure-5.42.
4.13.3.1. ELEFAN 1
Through length frequency data of Lutjanus lutjanus, whole data (all individuals) 2007 The asymptotic length (L∞) and growth parameter (K) was calculated by ELEFANI program using Von Bertallanfy Growth Function and growth curve of best fit and values of growth curve of best fit and values of L∞ 39.38, K 0.380 and score 0.178 were obtained by ELEFAN 1.
4.13.3.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value on a log scale, and 10 best
196
scores were highlighter , this is enabling selection of the “best” combination of
L39.38 and K 0.530, Figure 4.43-4.44.
Figure 4.43. Estimation of K for A. Figure 4.44. Estimation of K by emploing intermedius by emploing ELEFAN-1 of Shepherd’s method for L.lutjanus (all L.lutjanus (all individuals) 2007. individuals) 2007.
4.13.3.3. Powell-Wetherall plot
Through this method values of L∞ and Z/k were stimulated through a sample representing a steady state population by pooling a time series of length frequency data with constant size class. Figure 4.45
Figure 4.45. Powell –Wetherall plot for L. lutjanus (all individuals) 2007
197
4.13.3.4. Analysis of Growth Increment of L. lutjanus (all individuals) 2007.
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data was L∞, 38.39 and K , 0.380.
4.13.3.4.1. Gulland and Holt plot
Preliminary growth parameters were estimated by growth increment data , which based under VBGF growth rate decline linearly with length reached zero at and residuals of plot were used for inferences on seasonality of growth, in present study values of L ,38.39 and K 0.502 were estimated plot, Figure 4.46.
4.13.3.4.2. Munro’s plot
Values of growth parameters for L. lutjanus (combined) 2006, were obtained by
Munro’s plot is based on Munro(1982) were L 38.39 and K, 0.517,and graph was plotted. Figure 4.47
Figure 4.46. Gulland and Holt Plot for Figure 4.47. Munro’s plot based on (Munro Lutjanus lutjanus (all individuals) 2007. 1982) for Lutjanus lutjanus 2007.
4.13.3.5. Mortality estimation
Several programs are use for estimation of mortality rates, in present study FiSAT II was used for estimation of mortality .i.e. total mortality (Z) from steady state sample and length converted catch curve, natural mortality (M) by the steady state population.
198
4.13.3.5.1. Total mortality (Z)
4.13.3.5.1.1 Length converted catch curve
Total mortality for L. lutjanus (combined) for the year 2007 and Z/yr was obtained as (Z/yr) 0.71 (C:I-2.09 to 3.50) for Z=0.71;M at (26ºC)=0.85:F=0.14, E0.20, and Length converted catch curve was plotted by length frequency data with constant size class, Figure 4.48-4.49.
Figure 4.48. Length converted catch Figure 4.49. Length converted catch curve curve for L. lutjanus (all individuals) for L. lutjanus (all individuals) 2007, for 2007,darkened full dots represent the estimation of total mortality (Z). points used in calculating through least square linear regression and the open dots represent the points either not fully recruited,
4.13.3.5.1.2. Jones / Von Zalinge plot
In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve, Figure 4.49.
4.13.3.5.2. Total mortality (Z) from mean length
4.13.3.5.2.1. Beverton and Holt model (1956)
For this study for the data of L. lutjanus (all individuals) 2007 through Beverton and Holt plot and estimated the value of Z: 0.420/year, it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by
199 negative exponential decay and that L is estimated from steady state population data of size frequency.
4.13.3.5.2.2. Ault and Erhardt method
This method is used for short live life span tropical species , therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally Z for Lutjanus lutjanus (all individuals ) 2007 was 0.420.
4.13.3.5.3. Natural mortality (M)
In FiSAT II for estimation of natural mortality (M) two empirical and one analytical model were used.
4.13.3.5.3.1..Rikhter and Efanove’s method
In present study this model was used to estimate the natural mortality (M) was 0.152/year to age at which 50% of the stock reaches the age of “ massive spawning”
(tmass).
4.13.3.5.3.2. Pauly’s Equation
Natural mortality estimated by Pauly’s was 2.2471/year .It were derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ is available after (cm),K (year•¹ ) and temperature (mean annual habitat temperature (26ºC).
4.13.3.6. Recruitment pattern
In this study plot for recruitment pattern was generated by length frequency data of Lutjanus lutjanus (all individuals) 2007, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class, Figure 4.50.
200
Figure. 4.50. Recruitment pattern of Lutjanus lutjanus (combined) 2007
4.13.3.7. Probabilities of Capture
Length frequency data of L. lutjanus (combined) 2006 was used for estimation of probabilities of capture by the gill net option and curve was obtained for this study gill net selection curves was obtained its characterized by strong left hand and right hand by normal curves, Figure 4.51.
Figure 4.51.Probability of capture of Figure 4.52 Length based virtual L. lutjanus (all individuals) 2007 by population analysis L. lutjanus (all gill net. individuals) 2007.
201
4.13.3.8. Virtual Population analysis
From length frequency data of total catch Lutjanus lutjanus (all individuals) during the year of 2007 was used to generate the plot of virtual population to analyzed the population structure by Jones and Von Zalinge method, 1981 Figure 4.52.
4.13.3.9. Relative Yield – Per Recruit and Biomass per Recruit
Knife –edge selection Relative Y/R and B/R analysis, and Relative-yield-Per- recruit is based upon Beaverton and Holt model, 1996, presented as Beaverton and Holt model, 1966, modified by Pauly and Soniano,1986, in present study plots were generated as Figure 4.53-4.54 and values of recruitment analysis shown at Table 4.13.10. The maximum sustainable yield (MSY) can be attained with an exploitation rate of 1.0, the present exploited rate was 0.507. The results indicated that the L. lutjanus are not exploiting above the maximum sustainable yield. To increase the fishing needs is required the other factors including careful analysis and focus on selected areas for fishing and improve the capability of processing and market availability of enhanced products.
Figure 4.53. Yield isopleths /Recruit Figure 4.54. Relative yield-per-recruit analysis (Knife-edge selection) for and E=1.0 and Lo/Lo biomass-per recruit L lutjanus (all individuals) 2007. for L. lutjanus (all individuals) 2007.
202
Table 4.10. Relative analysis recruitment analysis results 2007.
4.14.3.10. Maximum length estimation
The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law. Table- 4.10
L* = a+ 1/a. p
Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion
L max= intercept of regression live with probability. Figure- 4.55.
Figure 4.55 Predicted maximum length of L. lutjanus (combined) 2007, based on extreme value theory (Formation et al., 1991).
203
4.13.4. Estimation of population dynamics parameters for L. lutjanus (all individuals) 2005-2007(Three years combined)
The section otolith based length-at–age data seemed to use to determine the growth of L. lutjanus. The maximum observed age was estimated as 11 years, parameters of
Von Bertalanffy equation L∞ , K and t0 estimated by the VONBIT software (Stamatopoulos, C. 2005).The data was fitted to Von Bertalanffy growth for male, female and mixed (all individuals) on yearly basis. The difference was observed between the estimated length and growth equation parameters. The Von Bertalanffy plot curve showed estimated age and coefficient of correlation of males, females and all individuals shows good relations. The values of L∞, K and t0 for males, females and all individuals are given at Table 4.14.12-4.14.25.
Length frequency data of Lutjanus lutjanus was used for estimations of different parameters (e.g., L∞, K, C, M, Z, etc.) and predict yield or stock-related attributes given certain fishing scenarios on yearly basis by sex and as a whole for three years (2005-2007). The observed extreme length and predicted extreme length (Lmax) were estimated, initially ELEFAN 1 was used to estimate the values of L∞ and K for obtain the VBGF growth curve, the best value of growth constant estimated by ELEFAN 1 routine. The optimized growth curve was superimposed on the restructured length frequency histograms, Figure 4.56.
Figure 4.56. L. lutajanus whole data (all individuals) three years,2005-2007 , length frequency and fitted Von Bertalanffy growth curve.
204
4.13.4.1. ELEFAN 1
Through length frequency data of Lutjanus lutjanus (whole data three years) growth curve of best fit and values of L 30.00, k 0.380 and score 0.150 were obtained by ELEFAN 1,Figure 4.57.
4.13.4.2. Shepherd’s method
This method is a similar to ELEFAN 1 and in present study through this a plot S value with (Smax was standardized to 1) generated for rang of K value on a log scale, and 10 best scores were highlighter, this is enabling selection of the “best” combination of
L30.00 and K 0.151, Figure 4.58.
Figure 4.57 Estimation of K for A. Figure 4.58 Estimation of K by emploing intermedius by emploing ELEFAN-1 of Shepherd’s method for (all individuals) L.lutjanus (all individuals) 2005-2007. 2005-2007.
4.13.4.3. Powell-Wetherall plot
The values of L∞ and Z/k were stimulated through this method by a sample representing a steady state population by pooling a time series of length frequency data with constant size class. Figure. 4.59.
205
Figure 4.59. Powell –Wetherall plot for L. lutjanus (all individuals) 2005-2007.
4.13.4.4. Analysis of Growth Increment of Lutjanus lutjanus (Combined)
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data was L , 30.00 and K , 0.151.
4.13.4.4.1. Gulland and Holt plot
Preliminary growth parameters were estimated by growth increment data, which based under VBGF growth rate decline linearly with length reached zero at and residuals of plot were used for inferences on seasonality of growth, in present study values of L ,30.00 and K 0.154 were estimated plot, Figure 4.60.
4.13.4.4.2. Munro’s plot
Values of growth parameters for L. lutjanus (female) 2006, were obtained by
Munro’s plot is based on Munro (1982) were L 30.00 and K, 0.802,and graph was plotted, Figure 4.61.
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Figure 4.60. Gulland and Holt Plot. For L Figure 4.61.Munro’s plot based on .lutjanus whole data three years(all (Munro 1982) L. lutjanus whole data individuals) 2005-2007. three years(all individuals) 2005-2007
4.13.4.5. Mortality estimation
Several programs are use for estimation of mortality rates, in present study FiSAT II was used for estimation of mortality .i.e. total mortality (Z) from steady state sample and length converted catch curve, natural mortality (M) by the steady state population.
4.13.4.5.1 Total mortality (Z)
4.13.4.5.1.1. Length converted catch curve
Total mortality for Lutjanus lutjanus (all individuals) for the year 2007 and Z/yr was obtained as (Z/yr) 0.87 (C:I-2.09 to 3.50) for Z=0.87;M at (26ºC)=0.85:F=0.14, E0.20, and Length converted catch curve was plotted by length frequency data with constant size class, Figure 62.
207
Figure 4.62. Length converted catch Figure .4.63 Jones and Van Zalling plot curve for L. lutjanus (all individuals) for estimation of total mortality (Z) of L. 2005-2007, darkened full dots represent lutjanus, (all individuals) 2005-2007 the points used in calculating through least square linear regression and the open dots represent the points either not fully recruited, for (all individuals) whole data three years,2005-2007 .
4.13.4.5.1.2. Jones / Von Zalinge plot
Jones and Van Zalling plot used for estimation of total mortality (Z) and generated cumulative plot as an early form of length converted catch curve. Figure. 4.63.
4.13.4.5.2 Total mortality (Z) from mean length
4.13.4.5.2.1. Beverton and Holt model (1956)
In present study Beverton and Holt plot was used for estimation of (Z) the whole data of L. lutjanus (all individual) 2005-2007 and the obtained value of Z: 0.389/year ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that L is estimated from steady state population data of size frequency.
4.13.4.5.2.2 Ault and Erhardt method
Through this method (Z) estimated for L. lutjanus (all individuals) whole data 2005- 2007 generally this method is used for short live life span tropical species, therefore
208 this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally estimated Z was 0.420/year.
4.13.4.5.3. Natural mortality (M)
For estimation of natural mortality (M) two empirical and one analytical model were used in FiSAT II.
4.13.4.5.3.1. Rikhter and Efanove’s method
Rikhter and Efanove’s method model was used to estimate the natural mortality (M) and estimated (M) was 0.109/year at 50% of the stock reaches the age of “ massive spawning” (tmass).
4.13.4.5.3.2. Pauly’s Equation
Natural mortality estimated by Pauly’s was 0.48121/year, derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L is available after the L (cm),K (year•¹) and temperature (mean annual habitat temperature (Cº).
4.13.4.6. Recruitment pattern
Recruitment pattern was generated by length frequency data of Lutjanus lutjanus (all individuals) whole data 2005-2007, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class, Figure 4.64.
Figure 4.64. Recruitment pattern of L. lutjanus all individuals (2005-2007).
209
4.13.4.7. Probabilities of Capture
Length frequency data of L. lutjanus (all individuals) 2005-2007 was used for estimation of probabilities of capture by the gill net option and curve was obtained.
The different probabilities at length size of 25% (L25 was 2.60 cm and L50 3.66cm and
L75 4.48cm. The obtaining values showed the high catching probability of the small sized individuals by the gill net fishing. Figure 4.65.
Figure.4.65.Probability of capture of L. Figure 4.66. Length based virtual population lutjanus all individuals three years analysis L. lutjanus all individuals three years (2005-2007). (2005-2007)
4.13.4.8. Virtual Population analysis
The results obtained through analysis showed maximum fishing mortality, figure 4.65.Estimated from length frequency data of total catch L. lutjanus (all individuals) during the year of 2005-2007 was used to generate the plot of virtual population to analyzed the population structure.Figure.4.66.
4.13.4.9. Relative Yield – Per Recruit and Biomass per Recruit
The Knife –edge selection of FiSAT-II was used to determined the yield per recruit and biomass per recruit which calculated the values of E10= 0.359, E50= 0.285 and
Emax: 0.431. The obtaining value of M/K is 0.900. The result showed that the level of E is lower as compared to (Y/R). The maximum sustainable yield (MSY) can be
210 attain with an exploitation rate of 1.0, present exploitation rate ratio was 0.507. The present obtaining results indicated that the L. lutjanus is not exploited above the maximum sustainable yield in present study plots were generated as Figure 4.67-4.68. The values of recruitment analysis shown at Table 4.11.
Figure 4.67. Yield isopleths /Recruit Figure 4.68 Relative yield-per-recruit and analysis (Knife-edge selection) for L. E=1.0 and L0/L0 biomass-per recruit for L. lutjanus (all individuals) 2005-2007. lutjanus (all individuals) 2005-2007.
Table 4.11. Relative analysis recruitment analysis results (all individuals) 2005-2007
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4.13.10. Maximum length estimation
The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law. Figure 4.69.
L* = a+ 1/a. p
Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion L max= intercept of regression live with probability
Figure 4.69. Predicted maximum length of L. lutjanus (all individuals) whole data 2005-2007.
In present study through population dynamics study it was observed the small size fished by tidal trap nets in creek areas and in maximum size L. lutjanus were captured by trawl nets in off shore waters and found only main fish markets of the province, comparative statements for the whole data of three years (2005-2007) study of L. lutjanus by sex (Male and Female) and all individuals are shown at Table 4.12 to 4.25.
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Table 4.12. Values of L & K estimated by different routines of Fi SAT II for Lutjanus lutjanus (Male) 2005 ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 24.68 24.68 24.65 24.68 24.68 24.00 24.68
K 0.312 0.560 0.340 1.068 1.208 -0.002 0.460
Table 4.13. Values of L & K estimated by different routines of FiSAT II for L. lutjanus (Male) 2006 ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 39.38 39.38 39.39 38.37 39.38 40.00 38.33
K 0.310 0.310 0.350 0.521 0.517 0.486 0.520
Table 4.14 Values of L & K estimated by different routines of FiSAT II for L. lutjanus (Male) 2007 ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 38.33 38.33 38.33 38.33 38.33 38.33 38.33
K 0.390 0.390 0.100 0.522 0.538 0.482 0.520
213
Table 4.15. Values of L & K estimated by different routines of Fi SAT II for Lutjanus lutjanus (Female) 2005 ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 38.33 38.33 38.33 59.24 38.33 38.33 38.33 K 0.280 0.370 0.100 0.280 0.538 -0.001
Table 4.16. Values of L & K estimated by different routines of Fi SAT II for L. lutjanus (Female) 2006
ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 38.33 38.33 38.33 59.24 38.33 40.09 38.33 K 0.520 0.520 0.290 0.522 0.538 0.486 0.520
Table 4.17. Values of L & K estimated by different routines of Fi SAT II for L. lutjanus (Female) 2007.
ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT L 38.33 38.33 38.33 59.24 38.33 38.33 38.33 K 0.190 0.390 0.100 0.280 0.538 0.190
214
Table 4.18.Values of L & K estimated by different routines of Fi SAT II for L. lutjanus (all individuals ) 2005. ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT L 39.38 39.38 39.38 39.38 39.38 39.38 39.38
K 0.530 0.530 0.390 0.520 0.517 0.517 0.517
Table 4.19. Values of L & K estimated by different routines of Fi SAT II for L. lutjanus (all individuals ) 2006 ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 39.38 39.37 39.38 39.38 39.38 39.38 39.38 K 0.260 0.540 0.140 1.700 0.517 0.486 0.530
Table 4.20 Values of L & K estimated by different routines of FiSAT II for L. lutjanus (all individuals) 2007 ELEFAN VBGF SHEPHERDS GULLAND AND MUNRO’S FABEN’S JONES AND VAN PLOT METHOD HOLT PLOT METHOD METHOD ZALIING PLOT
L 38.33 38.32 38.33 38.33 38.33 38.33 38.33
K 0.390 0.370 0.200 0.522 0.538 0.001 0.390
215
Table 4.21. Estimations of total mortality (Z) by length converted catch curve routine FiSAT II L. lutjanus A. Male B. Female and C. all individuals of three years (2005-2007) A (Male) 2005 Z(L Y/R) 0.52(C1:-3.56 to 4.60)
2006 Z(L Y/R) 0.96(Cl:- 4.91 to 6.83)
2007 Z(L Y/R) 1.35 (Cl:-3.94 to 6.65)
B (Female) 2005 Z(L Y/R) 0.50(C1:-0.16 to 1.17)
2006 Z(L Y/R) 1.47(Cl:- 2.72 to 5.67)
2007 Z(L Y/R) 0.64 (Cl:-1.01 to 2.30)
C (All individuals) 2005 Z(L Y/R) 1.18(C1:-4.32 to 6.69)
2006 Z(L Y/R) 1.57(Cl:- 5.73 to 8.86)
2007 Z(L Y/R) 1.24 (Cl:-0.60 to )
216
Table 4.22 .Natural mortality ( M) of L. lutjanus estimated by FiSAT II during three years 2005-2007 (Male, Female and all individuals)
Sex /Year Richter and Efanov’s Method Pauly’s Method
Male
2005 / Year 0.118 0.5486 2006 / Year 0.180 1.4905 2007 / Year 0.152 2.0257
Female 2005 / Year 0.110 1.2453
2006 / Year 0.110 0.4981 2007 / Year 0.180 0.6192
Combined
2005/year 0.110 1.2161 2006/year 0.151 0.1520 2007/year 1.054 2.2471
217
Table 4.23 .Total mortality ( Z) of Lutjanus lutjanus estimated by FiSAT II during three years (2005-2007)
Beverton and Holt Method Ault and Erhandt
Male
2005 / Year 0.313 0.315 2006 / Year 0.220 0.227 2007 / Year 0.223 0.230 Female 2005 / Year 0.160 0.130 2006 / Year 0.405 0.420 2007 / Year 0.033 0.027 Combined
2005/year 1..014 2..001 2006/year 0.335 0.337 2007/year 0.420 0.420
218
Table 4.24. Estimation of Growth performance indices of Lutjanus lutjanus during three years (2005-2007)
Male Female Combined Whole data (Three years)
2005 1.989 2.533 2.517 2.238 2006 1.991 2.130 2.770 2.241 2007 2.517 2.160 3.130 2.258
Table 4.25. Estimated values by FiSAT II as prediction of the maximum length from extreme value for L. lutjanus (2005-2007)
Year Prediction Value
2005 23.50 cm, 22.17-23.93.cm 2006 37.50cm, 36.16-38.46cm 2007 37.45, 35.14-36.46cm
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5. Results Lutjanus johnii (Bloch, 1792)
Figure. 5.1. Lutjanus johnii 15.2cm(TL).
English name: John's Snapper, Big-scaled Bream, One Spot Snapper, Golden Snapper, Spotted-scale Sea-perch, John's Sea-perch, John's Sea perch, Moses Perch, Finger mark Bream, Finger mark Sea perch, Snapper, Spotted-scaled Sea Perch.
Local Names: Hiro,Hira, Kunla, Kanalcha Maximum length (TL) 70 cm Conmen length: 50 cm Maximum weight (gm) 1000 gm Common weight: 3-4000 (gm)
Synonyms of Lutjanus johnii (Bloch 1792)
Anthias johnii (Bloch,1792),Coius catus (Buchanan 1822), Diacope xanthozona, (Bleaker 1845), Lutjanus johnii, (Bloch 1792 ),Mesoprion yapilli (Cuvier 1828), Serranus pavoninus (Valenciennes 1831), Sparus tranquebaricus (Shaw1803), Lutjanus johni (Bloch, 1792), Pinjalo pinjalo (Bleeker).
Distinguish and Morphometric Characters
Lutjanus johnii is commonly known as finger mark John’s snapper or spotted scale sea perch called ‘Goldy’ because its golden and silvery coloration, a dark large blotch located approximately two third above lateral line at mid body. Generally yellow with
220 a bronze to silvery sheen, shading to silvery white on belly and underside of the head. A large black blotch mainly above the lateral line below the anterior dorsal-fin rays. Dorsal profile of head steeply sloped. Pre orbital width equal to eye diameter or larger. Preopercular notch and knob poorly developed. Scale rows on back parallel to lateral line. Center of each scale often with a reddish-brown spot, giving an overall appearance of series of horizontal lines on side of body. Dorsal spines (total): 10, Dorsal soft rays (total): 13 - 14, Anal spines: 3, Anal soft rays: 8. Longitudinal rows of scales above lateral line parallel to it anteriorly, but sometimes appearing to rise obliquely somewhat below posterior part of spinous or soft dorsal fin. Scale rows above lateral line parallel to it under posterior part of spinous dorsal fin, ascending somewhat only below posterior part of soft dorsal fin. A round black spot, larger than eye, on back, mainly above lateral line, below anterior soft dorsal rays (sometimes absent in large adults).Figure-5.1.
Habitat: Lutjanus johnii (John’s snapper) is a trawling fish , caught from bottom trawl and trap net, generally found at Shallow coastal waters including mangrove area , also present down to depth of 80 meter, feed on bottom living invertebrate and fishes.
Distribution: Lutjanus johnii is Reef associated, rocks, deep sea, estuarine fish, some time in lower reaches of freshwater streams distributed throughout the world specially Indo –West Pacific , found from East Africa to Fiji and Northern Australia to South Japan ,hard bottom in habit at 80 m depth.
5.1 Size Frequency Distribution
5.1.1. Year 2005
During the year 2005 total 622 specimens of Lutjanus johnii were studied in which 201 were male,215 female and 206 were found juvenile or unsex , graphs regarding size class distribution were plotted from pooled data where the minimum size of specimen were observed during the month of September and October at 8 cm (TL) with 26gm fish weight (FW), otolith wt was 0.224 gm and size was 0.0212 and scale size was o.1, maximum size in July where size was 75 cm (TL) with 7550 gm weight, otolith weight was 3.671 gm and size was 1.421 cm , scale size was 4.1 and in
221
December size was 73 cm (TL) with 6420 gm weight , otolith wt was 1.821 gm and size 3.1 mm were observed during the year 2005.Graph. 5.1- 12.
5.1.2. Year 2006
During the year 2006, 525 specimens of Lutjanus johnii were studied in which 207 were male,211 female and 107 were found juvenile or unsex , graphs regarding size class distribution were plotted from pooled data where the minimum size of specimen were observed during the month of August ,September and October at 9 cm(TL) with 28 gm (FW) fish weight, otolith wt was 0.223 gm and size was 0.0211 and scale size was 0.1, maximum size in August, where size was 73 cm (TL) with 6100 gm weight, otolith weight was 2.94 gm and size was 1.256 cm , scale size was 4 and in October size was 72 cm(TL) with 6567 gm weight , otolith wt was 1.431 gm and size 0.6932 mm were observed during the year 2006.Graph 5.13-24.
5.1.3. Year 2007
During the year 2006, 482 specimens of Lutjanus johnii were studied in which 211 were male,200 female and 71 were found juvenile or unsex , graphs regarding size class distribution were plotted from pooled data where the minimum size of specimen were observed during the month of august ,September and October at 9 cm(TL) with 28 gm (FW) fish weight, otolith wt was 0.223 gm and size was 0.0211 and scale size was 0.1, maximum size in August, where size was 73 cm (TL) with 6100 gm weight, otolith weight was 2.94 gm and size was 1.256 cm , scale size was 4 and in October size was 72 cm(TL) with 6567 gm weight , otolith wt was 1431 gm and size 0.6932 mm were observed during the year, Graphs 5.25 –36. The whole specimens studied during three years (2005-2007) mixed population on yearly basis are shown at Graphs 5.37- 40.
222
Graph 5.1 Graph 5.7
Graph 5.2 Graph 5.8
Graph 5.3 Graph 5.9
Graph 5.4 Graph 5.10
Graph 5.5 Graph 5.11
Graph 5.6 Graph 5.12
Graph 5.1- 5.12 Size frequency distribution of Lutjanus johnii 2005.
223
Graph 5.13 Graph 5.19
Graph 5.14 Graph 5.20
Graph 5.15 Graph 5.21
Graph 5.16 Graph 5.22
Graph 5.17 Graph 5.23
Graph 5.18 Graph 5.24
Graphs 5.13 – 24. Size frequency distribution of Lutjanus johnii 2006.
224
Graph 5.25 Graph 5.31
Graph 5.26 Graph 5.32
Graph 5.27 Graph 5.33
Graph 5.28 Graph 5.34
Graph 5.29 Graph 5.35
Graph 5.30 Graph 5.36
Graph 5.25 – 5.36 Size frequency distribution of Lutjanus johnii. 2007.
225
Graph 5.37
Graph.5.37. Total No’s of specimens of Lutjanus johnii studied all individuals (2005-2007) Graph 5.38
Graph. 5.38 .Total No’s of Specimens of Lutjanus johnii studied all individuals (2005).
226
Graph 5.39
Graph. 5.39. Total No’s Specimens of Lutjanus johnii studied all individuals (2006).
Graph 5.40
Graph 5.40. Total No’s of Specimens of Lutjanus johnii studied all individuals (2007)
227
A
B
C
D
Figure. 5.2 Size distribution of Lutjanus johnii collected from Karachi Fish Harbor (2005-2007), A-8.5 cm,B-12 cm,C-14.5 cm and D-16 cm TL.
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5.2. Analysis of Gonads
5.2.1. Macroscopic and Histological examination of gonads
The Gonads of Lutjanus johnii were observed visually than histologically as shown in table 3.1 and 3.2. The smaller size class of L. johnii <5cm to <10cm TL posses thread like, thin and semitransparent gonads. The gonads of <10cm TL size class were large as compared to smaller size class contains tissues with early germ cell. Distinguishable tissues of testicular material and ovarian first observed in individuals of 20cm TL, both were immature stage length class. Testicular zone in male contains spermatogonia and early stage of spermatogenesis while female contained previtellogenic stage acolytes were attached with the body cavity contains connective tissues predominantly with stroma cells, during spawning season male specimens were dominant in smaller size class rather than the largest size class with the milky testicular structure with blood capillaries, female specimens were observed during this season at <25cm TL to <35cm TL and matured at <58cm TL and during non spawning season such male at <15cm TL to <25cm TL were observed as immature in slightly larger in size with connective tissue, brown bodies, without spermatogenesis. Female specimens observed during the spawning season the ovarian testicular zone contain developing oocytes such as preinuleolar, yolk granules and previtellogenic stages.
During the study it was observed that the Lutjanus johnii female are functional and fully matured in large size at 58cm to 60cm TL, contained mature yolk granule stage oocytes and vitellogenic oocytes, Figure.5.3 and 5.4 to 5.10.
229
(I) 10cm TL (II) 20cm TL (III) 25cm TL (IV) 35 cm TL
(IV) 45 cm TL (V) 55cm TL (VI) 65cm TL (VIII) 74 cm TL
Figure. 5.3. Macroscopic observation of gonads showing different maturity stages in Lutjanus johnii (Stage-I to VI).
230
Figure 5.4 Histological section of immature ovary of Lutjanus johnii shows ovarian lamella (OL) and Previtellogenic acolytes (PVO). Scale bare is 100 µm.
Figure 5.5 Histological section of developing ovary of Lutjanus johnii shows primary growth and oocytes (PGO) cortical alveolar oocyte (CAO). Scale bare is 100 µm.
231
Figure 5.6 Histological section of fully mature ovary of Lutjanus johnii shows late vitellogenic oocyte (LVO), yolk granule (YG) and zona radiate (ZR). Scale bare is 100 µm.
Figure. 5.7 Histological section of nearly spent ovary contains postovulatory follicles (POF) and late vitellogenic oocyte (VO) Scale bare is 50 µm
232
Figure 5.8 Photomicrographs of histological section of testis of L. johnii immature phase show lumen of lobule (Lu), spermatogonia (SG). Scale bare is 20 µm.
Figure. 5.9 Photomicrographs of histological section of testis of L. johnii mature male shows spermatogonia (SG), spermatides (St), spermatocytes (Sc) and spermatozoa (Sp). Scale bare is 100 µm.
233
Figure 5.10 Photomicrographs of histological section of testis of L. johnii maturing male show spermatogonia (SG) and spermatocytes (Sc). Scale bare is 200 µm.
5.2.2. Monthly variation in maturity stages of Lutjanus johnii
The female specimens were observed fully matured at 50 cm (TL) with stages III and IV during the months of November and December. In the months of April and May immature or resting stages were observed, during the months of June and July initial stage II of mature ovaries were observed, frequencies of mature ovaries were rises during the months of October, November and December.
In present study different stages of maturation were observed, stage II ovaries were found first during the months of June and July, frequency of mature female were in September rises up to November and December, few female with opaque granules oocytes and post follicles (POF) were studied and spent ovaries were found in October .i.e. Dark reddish / brown in color. Fully matured females with stages VI and VII were observed in the months of September and October and mostly spent observed in January and March and in e months of April and May immature/ stages I & II were observed. Graph.5.41 to 5.76
234
Graph 5.41 Graph 5.47
Graph 5.42 Graph 5.48
Graph 5.43 Graph 5.49
Graph 5.44 Graph 5.50
Graph 5.45 Graph 5.51
Graph 5.46 Graph 5.52
Graphs. 5.41 –5.52. Percentage frequency distribution for maturity stages 2005.
235
Graph 5.53 Graph 5.59
Graph 5.54 Graph 5.60
Graph 5.55 Graph 5.61
Graph 5.56 Graph 5.62
Graph 5.57 Graph 5.63
Graph 5.58 Graph 5.64
Graphs 5.53 –5.64. Percentage frequency distribution for maturity stages 2006.
236
Graph 5.65 Graph 5.71
Graph 5.66 Graph 5.72
Graph 5.67 Graph 5.73
Graph 5.68 Graph 5.74
Graph 5.75 Graph 5.69
Graph 5.70 Graph 5.76
Graphs 5.65- 5.76. Percentage frequency distribution for maturity stages 2007.
237
5.3 Marginal increments analysis (MIA)
The mean monthly incensement (MI) on section otoliths were measured by building in software scale in millimeter unit. The mean values of marginal increments were plotted against each months, plot showed that the value of mean monthly increments was starting to rise in the month of May to July and peak observed in September when maximum values were 1 mm observed and decline was .08- 0.25 mm observed from December to April. The rise and decline of mean monthly marginal incremental values verified that the only one opaque growth zone formed in a year, Graph. 5.77
Graph 5.77
Graph 5.77. Marginal increment analysis of Lutjanus johnii (2005-2007)
5.4. Estimation of L 50% sexual maturity
Logistic curve was used for determination of size at 50% maturity by non linear regression analysis of combined data of three years (2005-2007) for male and female sexes were used. Results shown population of male specimens of Lutjanus johnii attained L50 % maturity at 47cm TL and female specimens of Lutjanus johnii 57cm TL. The logistic curve for both sex shows best fit to proportional mature data. The coefficient of correlation for males are r2 1.01 and r2 0.99 for females. Graph 5.78- 5.79.
238
Graph 5.78
Graph 5.78. Size at 50 % maturity of Lutjanus johnii (Male) during three years
Graph 5.79
Graph. 5.79. Size at 50 % maturity of Lutjanus johnii of female specimens.
5.5. Oocytes size frequency distribution of L. johnii during three years (2005-07)
The oocyte diameter distribution of L. johnii shows the length of spawning season and frequency distribution of oocyte in fully mature ovarian shows type of fecundity. During the peak spawning season two fully matured females with stage V and VI were obtained from every year (2005,2006 and 2007). The study of ovarian development stags shown that the Lutjanus johnii is a bimodal distribution, the hydrate oocytes visible in small size developing oocyte skewed to
239 the left side and the second set of the medium size oocyte were few in numbers and the third set of oocyte consist of large size oocyte, which skewed to the right side. The small size class of oocyte contains the chromatin nucleoli and previtellogenic oocyte while the larger size class of oocyte consisted of mainly yolk granule oocyte and late vitellogenic oocyte. The trend of oocyte distribution showed that this specie of Family Lutjanidae has determinate fecundity. The oocyte size frequency analysis in 20 cm TL female contained smallest oocyte i.e. 0.042 – 0.140 mm in size, which were chromatin nuclear stage oocyte which were skewed towards the left side. The 30 cm TL female was obtained at the peak spawning season showed the same trend the set of small size oocyte was skewed towards the left side. In both the ovaries large set of oocyte i.e. 0.48 – 0.7mm were skewed towards the right side. The ovaries of 25 cm TL and 70.5 cm TL females were obtained in 2005 and 2007.The large size set of oocyte consist of predominantly on yolk granules and advance hydration stage oocyte. The size difference found in oocyte of Lutjanus johnii strongly favors this concept that the Lutjanids is a multiple spawnerpresence of small and the very large size oocyte showed that Lutjanus johnii spawns more than one time during spawning season. Graphs 5.80-5.84.
Graph 5.80
240
Graph 5.81
Graph 5.82
Graph 5.83
241
Graph 5.84
Oocytes diameters (mm)
Graphs 5.80-5.84 Oocytes diameter frequency distribution of four stages of L. johnii (stage-V) ripe ovary of females 40 cm to 55.5 cm, during the three year (2005-2007).
5.6. Fecundity
The fecundity of smallest observed fish of 24.5 cm in length and 338 gm in weight was calculated to have 149,223 eggs, and the largest fish of 75 cm in length has 1,974,769 eggs respectively. Fecundity of L. johnii shows a strong relationship with the length of the fish. The smaller size fish produced a less number of eggs and large size fish produced more number of eggs. The calculation of L. johnii fecundity showed a strong correlation between length of fish and fecundity. The results show the fecundity increases with increases in size of fish.
In present study mature females of stage (V-VI) ovaries were selected during 2005- 2007 and the relationship of fecundity and total length (cm) and weight (gm) were observed through log linear regression. The natural logarithm of fecundity, total length values were taken and relationship were described. The mean fecundity of 50 specimens of Lutjanus johnii is calculated to be 998,232 ± 180,490.In relationship of fish length (TL cm) and No’s of ova through regression analysis all observations of the coefficient of co relation shows positive trend and the slop (b) value is significant from the theoretical slop of 3.0, and relationship between fish weight (in gm) and No’ of ova was also observed. For fecundity of Lutjanus johnii five mature females were selected (stages V-VI) for the determination of the relationship between fecundity and total length and weight.
242
Log W=b +a log L = n=
Where:
F = Fecundity
W =Total weight of fish b = log length of fish (TL) a = counted eggs
L = length of fish
= correlation coefficient
The estimated values are as under:-
Log W = 1.489 x 1.590 r² = 0 .842 (n=30)
Relationship between fecundity and somatic weight of Lutjanus johnii were estimated, and between fecundity and length cm (TL), during the study it was observed that all above observations of the coefficient of co relation shows the positive trend and the slop (b) value is significant from the theoretical slop of 3.0.Graph. 5.85.
Graph 5.85
Graph 5.85 Relationship between annually potential fecundity with somatic weight gm of Lutjanus johnii during 2005-2007.
243
The relationship of fecundity – total length is as follows:
Log L = 6.597 x log L 1.448 r² = 0.981, (n = 30)
Graph 5.86
Graph 5.86 Fecundity of Lutjanus johnii during three years (2005-2007)
5.7. Percentage frequency distribution of Lutjanus johnii (male, female and juvenile)
Length frequency distribution data of gonadal maturity was used for plot from Microsoft excel program, shows the size class from < 10 cm TL to 20 cm TL were dominated as immature individuals. Immature males shown in gray color were first time observed in <10 cm TL size class and dominated the 61 cm to 70 cm TL size class and mature males shown in blank with white colored vertical lines were observed first time in < 11 cm size class Female shown black, white and brown color first time observed at <10 cm TL and dominant at 70 cm > TL. The size < 41 cm to 50 cm has three types of individuals including mature males and immature specimens. Graph. 5.87.
244
Graph 5.87
Graph.5.87. Percentage frequency distribution of gonadal stages of Lutjanus johnii during the year 2005-2007.
5.8. Length weight relationship
In present study the length weight relationship of L. johnii during three years (2005- 2007) were determined by use of logarithmic transformation, from pooled data of 2005-2007,statistical values of the regression analysis shown in the table- 5.1.The relationship equations of combined data of log length and log weight calculated yearly basis, shown no significant differences and the values of the coefficient of correlation (r²) were highly significant. The equations of linear regression data obtained from three (2005 – 2007) years. Length weight data to generate the plot and found regression equation of length weight relationship during the study were observed values are under:-
Log W=b x a log L = n=
2005 Log W=3.114 x- 1.934 = 0.977 n=515
2006 Log W=-2.018 x 3.172 = 0.983 n=468
2007 Log W= -1.999 x 3.162 =0.979 n=543
245
In all above observations the coefficient of co relation shows the positive trend and the slop (b) value is significant from the theoretical slop of 3.0. Graph-5.88-5.90.
Overall (male, Regression Log W = Log a + b Log L r2 P – Value female and unsexed
2005 (N=622) Log10 Weight = Log10 (-1.934) + 3.114 Log10 0.977 0.000
2006 (N=525) Log10 Weight = Log10 (-2.018) + 3.172 Log10 0.983 0.000
2007 (N=482) Log10 Weight = Log10 (-1.999) + 3.162 Log10 0.979 0.000
Table. 5.1 values of length weight relationship of Lutjanus johnii during three years (2005-2007)
Graph 5.88
Graph 5.88. Linear regression analysis for length weight Relationship 2005.
246
Graph 5.89
Graph 5.89. Linear regression analysis for length weight Relationship 2006.
Graph 5.90
Graph 5.90. Linear regression analysis for length weight Relationship 2007
247
5.9. Linear regression analysis
Regression analysis techniques have advantages for avoid bias the sampling time (Campana,1990) during the present study estimation of correlation the linear regression graphs on monthly basis with poled data were plotted for obtain the values (table.5.2) with the help of equation is “Y=b X and r2” between following:-
Fish weight(gm) and Fish length (TL)
Fish weight (gm) Otolith weight (gm)
Fish length (cm) and Otolith size (mm)
Fish length (cm) and Scale size (mm)
Whereas:
Y= Fish weight and X = TL
Y=Fish weight and X= OW (Otolith weight)
Y= Fish length and X = OS (Otolith size)
Y= Fish length and X = SS (Scale size)
The results of linear regression analysis of all above correlations shows strong significant values and no difference observed between theoretical slope with strong correlations, the coefficient of correlation r2 was higher in September and December (2005), in August, September and October (2006) and August, September and December (2007), further month wise relationship between Fish length (TL cm) Vs fish weight (gm), fish length Vs scale size, fish length Vs otolith size (mm) fish weight gm Vs otolith weigh (mg) by regression analysis shown at Graphs. 5.91-5. 223
248
Graph 5.91 Graph 5.97
Graph 5.98 Graph 5.92
Graph 5.99 Graph 5.93
Graph 5.94 Graph 5.100
\
Graph 5.95 Graph 5.101
Graph 5.102 Graph 5.96
Graph 5.91 – 5.102. Regression analysis between fish length (TL cm) and fish weight (gm) relationship of Lutjanus johnii ,2005.
249
Graph 5.103 Graph 5.109
Graph 5.104 Graph 5.110
Graph 5.105 Graph 5.111
Graph 5.106 Graph 5.112
Graph 5.107 Graph 5.113
Graph 5.108 Graph 5.114
Graph 5.103-114. Regression analysis between Length (TL cm) and weight (gm) relationship of Lutjanus johnii 2006.
250
Graph 5.115 Graph 5.121
Graph 5.116 Graph 5.122
Graph 5.117 Graph 5.123
Graph 5.118 Graph 5.124
Graph 5.119 Graph 5.125
Graph 5.120 Graph 5.126
Graph 5.115 –126. Regression analysis between Length (TL cm) and weight (gm) relationship 2007.
251
Graph 5.133 Graph 5.127
Graph 5.128 Graph 5.134
Graph 5.129 Graph 5.135
Graph 5.136 Graph 5.130
Graph 5.137 Graph 5.131
Graph 5.132 Graph 5.138
Graph 5.127 -138. Regression analysis between Fish weight(gm) –Otolith (mg) weight relationship 2005.
252
Graph 5.145 Graph 5.139
Graph 5.140 Graph 5.146
Graph 5.147 Graph 5.141
Graph 5.142 Graph 5.148
Graph 5.143 Graph 5.149
Graph 5.144 Graph 5.150
Graph 5.139-150. Regression analysis between Fish weight (gm)Otolith weight (mg) relationship 2006.
253
Graph 5.151 Graph 5.157
Graph 5.152 Graph 5.158
Graph 5.153 Graph 5.159
Graph 5.154 Graph 5.160
Graph 5.155 Graph 5.161
Graph 5.156 Graph 5.162
Graph 5.151 –162. Regression analysis between Fish weight (gm) Otolith weight (mg) 2007.
254
Graph 5.163 Graph 5.171
Graph 5.164 Graph 5.172
Graph 5.165 Graph 5.173
Graph 5.174 Graph 5.166
Graph 5.175 Graph 5.169
Graph 5.170 Graph 5.176
Graph 5.163-176. Regression analysis between Fish length (TL cm) and Otolith size (mm) 2005.
255
Graph 5.177 Graph 5.183
Graph 5.184 Graph 5.178
Graph 5.179 Graph 5.185
Graph 5.186 Graph 5.180
Graph 5.181 Graph 5.187
Graph 5.188 Graph 5.182
Graph 5.177- 188. Regression analysis between Fish Length (TL cm) Otolith size (mm) 2006.
256
Graph 5.195 Graph 5.189
Graph 5.196 Graph 5.190
Graph 5.191 Graph 5.197
Graph 5.192 Graph 5.198
Graph 5.193 Graph 5.199
Graph 5.194 Graph 5.200
Graph 5.189-200. Regression analysis between Fish length (TL cm ) scale size (cm) 2005.
257
Graph 5.201 Graph 5.207
Graph 5.202 Graph 5.208
Graph 5.203 Graph 5.209
Graph 5.204 Graph 5.210
Graph 5.205 Graph 5.211
Graph 5.206 Graph 5.211
Graph 5.201-211. Regression analysis between Total Length (TL cm) scale size (mm) 2006.
258
Graph 5.212 Graph 5.218
Graph 5.213 Graph 5.219
Graph 5.214 Graph 5.220
Graph 5.215 Graph 5.221
Graph 5.216 Graph 5.222
Graph 5.217 Graph 5.223
Graph 5.212–223. Regression analysis between Fish Length (TL cm) scale size (mm) 2007
259
Table 5.2. Linear regression analysis for TL (cm) and wt (gm) relationship of L. johnii collected from three diffetrent l variable. Months 2005 2006 2007
a B r2 a B r2 a B r2
January -26.09 0.007 0.916 +24.74 0.007 0.913 +27.51 0.006 0.931 February - 0.629 0.000 0.826 +25.35 0.007 0.915 +26.56 0.007 0.904 March -15.34 152.8 0.869 +27.18 0.006 0.969 + 28.26 0.006 0.908 April -1.108 0.000 0.912 +28.36 0.006 0.946 +28.41 0.006 0.932 May -0.977 0.000 0.821 +26.38 0.006 0.948 +27.01 0.007 0.937 June -0.962 0.000 0.797 +27.70 0.006 0.960 +29.76 0.006 0.936 July -0.232 17.28 0.946 +29.56 0.006 0.906 +30.51 0.006 0.931 August -28.55 20.08 0.941 +19.82 0.009 0.802 +17.34 0.009 0.846 September -25.89 18.99 0.911 +21.45 0.008 0.851 +19.34 0.008 0.874 October -12.16 14.24 0.921 +21.59 0.008 0.889 +30.50 0.006 0.930 November -14.66 14.80 0.915 +23.13 0.009 0.847 +23.31 0.008 0.870 December -15.02 16.31 0.993 +23.14 0.008 0.912 +23.86 0.008 0.901
260
5.9.1 Fish Length Vs Fish weight
Donated and pronounced R squared indicates how well data points fit a line or curve. In present study during the year 2005, 2006 and 2007 for linear regression analysis for fish length (TL) cm V/s fish weight (gm) shows strong correlations.
5.9.2 Fish Length (TL) cm V/s Scale Size (mm)
Donated and pronounced R squared indicates how well data points fit a line or curve. In present study during the year 2005, 2006 and 2007 for linear regression analysis for fish length (TL) cm V/s Scale size mm shows strong correlations
5.10. Estimation of Age and growth
5.10.1. Otolith morphology
Otolith of L. johnii was whitish to translucent in color, rhomboidal in shape with moderate thickness margins were wavy, laterally compressed slightly concave at distal surface Figures 5.11 to 5.17.
12.5 cm T. L.
Figure. 5.11. Whole otoliths of Lutjanus johnii 12.5cm (TL).
261
16.5 cm T. L.
Figure. 5.12. Whole otoliths of Lutjanus johnii 16.5 cm (TL)
20.5 cm T. L.
Figure. 5.13. Whole otoliths of Lutjanus johnii .20.5 (TLcm).
30.5 cm T. L.
Figure 5.14. Whole otolith of Lutjanus johnii. 30.5 (TL cm)
262
35.8 cm T. L.
Figure 5.15. Whole otolith of Lutjanus johnii. 35.8 TL cm
37.5 cm T. L.
Figure 5.16. Whole otolith of Lutjanus johnii A 39.5 cm (TL)
42 cm T. L.
Figure 5.17. Whole otolith of Lutjanus johnii 42 cm (TL).
263
5.10.2. Scale Observations
Figure 5.18 Scale of Lutjanus johnii 24.5 cm TL arrows showing growth rings.
Scales of L. johnii studied regarding growth rings the body covered with scales at posterior end with small teeth as projections ctenii, circuli form a concentric pattern over the course of year, relates with the environmental growth conditions, during late spring and warmer summer, as the growth of fish increase the circuli were form but during the winter season when slow growth were found scales were closer together appear broken and fragmented or incomplete, Figure- 5.18-5.19.
5.10.3. Sectioned otolith Vs whole otolith
In juveniles and small age individuals of lutjanus johnii the opaque growth zones were easily observed on whole otoliths rather than older age specimens therefore the fish grow then the otolith turned to opaque and growth zones were difficult to study as well as through sectioned otolith opaque growth zones were easy to study as compared to whole otolith.
5.10.4. Otoliths Vs Scales
Comparison between whole otolith and scales of lutjanus johnii were made both are have similar growth zones. But scales presented a lack of clearness in the ring formation and have no sequence with the greater numbers of circuli as compare to otolith of same individual.
264
I II
III IV
V VI
Figure 5.19. Magnified photographs of Lutjanus johnii scales shows different numbers of growth zones. i: 12 cm TL, ii: 18.5 cm TL, iii: 22.5 cm TL, vi: 30.5cm TL, V: 40 cm TL and VI 50.5 cm TL. Scale bar in all is equal to 2 mm.
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5.11. Age determination of Lutjanus johnii. Age and growth was estimated by the whole otolith of both specimen of Lutjanus johnii (Hector Antonio Andrade, 2003) as well as count numbers of opaque zones from sectioned otolith with the help of stereomicroscope attached with digital camera and images of sectioned otolith were analyzed with the help of image J software and radius of each section was measured at fixed scale as 2mm. Three years data (2005- 2007) was insert separately male, female and combined for estimation of relationship between age and growth of fish by Von Bertalanffy growth curve. Figure 5.20- 5.22.(A, B and C)
R:1
5.20 A
R:2 5.20 C
SA
------r5
------r4 ------r3
Figure 5.20. (A and B ) Sectioned otolith of Lutjanus johnii shows opaque zones “r” otolith radius (R); primordium (N), sulcus acoustics (SA), dorsal side (D) and ventral side (V).Scale bar is 2mm.
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R:4 5.21 A SA
V D
R:5 5.21 B
SA
N
R:6 5.21C . R SA
Figure 5.21. Sectioned otolith of Lutjanus johnii shows opaque zones “r” a, otolith radius (R); primordium (N), sulcus acoustics (SA), dorsal side (D) and ventral side (V) black dots shows growth rings. Scale bar is 2mm.
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R-7
1mm 5.22.A
SA
D
R-8
5.22.B
R-9
5.22.B
Figure. 5.22. Sectioned otolith of Lutjanus johnii shows opaque zones otolith radius, sulcus acoustics (SA), dorsal side (D) white dots shows growth rings .Scale bar is 2 mm.
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5.12. Determination of growth of Lutjanus johnii
Figure 5.23. Ven Bertalanffy Growth equetion.
Growth of Lutjanus johnii was estimated through growth rings were read from whole otolith and clearly counted by stereomicroscope teken picture from sectioned otolith of L. johnii, the observed data of growth rings counted from section otolith
In present study the sectioned otolith based length–at-age data of Lutjanus johnii were used for determination the growth curve through software’s, through von Bertalanffy growth model for males, females and overall individuals.
The model fitted with the all data sets, curve of growth model reduced beyond the + 8 age cohorts. The length at-age data of both sexes showed difference between males and females. The maximum observed age from sectioned otolith was 25 years. The von Bertalanffy plot curve demonstrates that the age of 1 year to 5 years had an average, from 8 years to 25 years attained the length of 20cm to 74cm TL for Lutjanus johnii. and plots were generated by Von Bertalanffy equation, through Von Bertalanffy growth medel Constantine Stamatppoulos, 1989 and ‘R’ statstical sotware as equation at Figure 5.23.
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5.12.1. Method for fitting von Bertalanffy growth parameters by linear regression analysis (Constantine Stamatppoulos and Caddy (1989).
Observations of growth rings at whole otolith were used to determine the age and growth by length at age data of Lutjanus johnii. Sectioned otolith based length at age data was used to determine the growth of Lutjanus johnii, maximum observed age was 9 years. The growth parameters of Von Bertalanffy equation L∞, L, t0 estimated by using VONBIT software (Stamatopoulos, C. 1989), values of parameters are given in Table-5.2-5.5, Data was fitted to the von Bertalanffy growth model for male, female and overall (mixed), observed difference between the age at length and estimated age by growth equation parameters.
The Von Bertalanffy growth function (VBGF) demonstrates that the age at 1 year to 8 year age shown an average but from 10 year to 20 years attained the length of 18 cm TL to 75 cm TL for present study the age and growth data was putted in a software yearly basis (2005-2007) observed and estimated from section otolith, by sex separately the observed age at length of Lutjanus johnii was putted the program generated estimated length with the age of specimens and the coefficient of correlation of males Graphs (5.24-5.26), females (5.27-5.29 and all individuals (mixed) (5.30-5.32) shown good correlation, values are shown at table -5.3-5.6.
Graph 5.224
270
Graph 5.225
Graph 5.226
Graph 5.224-226. Von Bertalanffy growth function (VBGF) fitted to length age data of Lutjanus johnii (male) 2005-2007.
271
Graph 5.227
Graph 5.228
Graph 5.229
Graph 5.227-229. Von Bertalanffy growth function (VBGF) fitted to length age data of Lutjanus johnii (female) of three years 2005-2007.
272
Graph 5. 230
Graph 5.231
Graph 5.232
Graph 5.230-232. Von Bertalanffy growth function (VBGF) fitted to length age data of Lutjanus johnii (all individuals) data of three years (2005-2007).
273
Graph 5.233
Graph 5.234
Graph 5.235
Graph 5.233- 5.235.Von Bertalanffy growth function (VBGF) fitted to length age combined data Lutjanus johnii (all individuals) during three years (2005-2007).
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Table.5.3 .Values of Von Bertalanffy growth curve model plotted for the data of Lutjanus johnii (Male) observed during 2005-2007.
Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination observation freedom L∞ t0 of R²
2005 0.064 0.977 857 855 79.945 -2.233 78.561- 81.428 -4.184 - -0.282
2006 0.064 0.977 900 898 79.988 -2.308 78.542 – 81.434 -2.308 - -4.323
2007 0.065 0.977 873 871 79.689 -2.179 78.198 – 81.180 - -4.079 - -0.280
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Table 5.4 .Values of Von Bertalanffy growth curve model plotted for the data of Lutjanus johnii (Female) observed during 2005-2007.
Year Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination observation freedom L∞ t0 of R²
2005 0.069 0.974 810 808 78.567 -2.072 77.062 – 80.071 -3.862 - -0.282
2006 0.065 0.977 948 946 79.579 -2.285 78.187 – 80.971 -4.278 – 0.294
2007 0.064 0.976 899 897 79.989 -2.283 78.548 – 81.43 -2.283 - -0.289
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Table 5.5 .Values of Von Bertalanffy growth curve model plotted for the data of Lutjanus johnii (all individuals/Combined) observed yearly.
Year Optimal K Co efficient of No of Degree of L∞ t0 Confidence limits at 95% determination observation freedom L∞ t0 of R2
2005 0.065 0.977 899 897 79.611 -2.237 78.170 – 81.052 -4.186 – 0.287
2006 0.065 0.976 891 889 78.587 -2.235 77.172 -80.051 -2.343 - 1.989
2007 0.065 0.977 899 897 79.611 -2.237 78.170 – 81.952 -4.186 -0.287
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Table 5.6 .Values of Von Bertalanffy growth curve model plotted for the combined data of Lutjanus johnii for three years 2005-2007.
Optimal K Coefficient of No of Degree of L∞ t0 Confidence limits at 95% determination observation freedom L∞ t0 of R²
Male 0.065 0.952 987 985 79.462 -2.193 78.003 – 80.922 -4.104 - - 0282
Female 0.066 0.968 987 985 78.658 -2.355 77.199 – 80.117 - 4.402 - -0.308
Combined 0.062 0.962 987 985 79.805 -2.509 78.345 – 81.265 - 4.710 - - 0.308
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5.12.2. Estimation of age by “R” statistical Software
The Von Bertalanffy growth equation (1957) was used for estimation generate the plot by same data of age (year) and length (TL cm) of Lutjanus johnii through ‘R’ software and the mean length and also observed length by same. Graph 5.236-42.
Graph 5.236
Graph 5.238
Graph 5.239
Graph 5.236-239.The Von Bertalanffy growth curves by “R” software A fitted to length age data of Lutjanus johnii (Male) 2005-2007.
279
Graph 5.240
Graph 5.241
Graph 5.242
Graph 5.240-5.242.The Von Bertalanffy growth curves by “R” software fitted to length age data of Lutjanus johnii (female) for three years(2005-2007).
280
5.12.3. Mean length and observed length
For further estimation of length frequency data of lutjanus johnii from three years (2005-2007) used for relationship between mean length and observed length through “R” statistical software by sex male , female and mixed data through plots. Shown at Graphs 5.243-5.45 (Male) and 5.246-5.48 (Female) Table, 5.7 (Male) and 5.8 (Female).
Graph 5.243
Graph 5.244
Graph 5.245
Graph 5.243- 5. 245.The mean length and observed length of Lutjanus johnii (Male) 2005-2007.
281
Graph 5.246
Graph 5.247
Graph 5.248
Graph 5.246 -5.48. The mean length and observed length of Lutjanus johnii (female) 2005-2007
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Age Mean Length Age Mean Length (Age) Mean Length (years) (cm) (years) (cm) Years (cm) 2005 N=622 2006 N=525 2007 N=482 0.5 10.5 0.5 10.5 0.5 10.5 1 12.7 1 12.7 1 12.6 1.5 15.3 1.5 15.2 1.5 15.2 2 17.1 2 17.1 2 17.1 2.5 19.6 2.5 19.5 2.5 19.5 3 21.1 3 21.1 3 21.0 3.5 23.7 3.5 23.6 3.5 23.6 4 25.3 4 25.3 4 25.3 4.5 28.2 4.5 28.1 4.5 28.1 5 29.6 5 29.6 5 29.6 5.5 32.2 5.5 32.1 5.5 32.1 6 34.0 6 34.0 6 34.0 6.5 36.3 6.5 36.2 6.5 36.2 7 38.4 7 38.3 7 38.3 8 40.5 8 40.5 8 40.5 9 42.0 9 42.0 9 42.0 10 42.7 10 42.7 10 42.7 11 44.1 11 44.1 11 44.1 12 45.8 12 45.8 12 45.8 13 48.5 13 48.5 13 48.5 14 49.8 14 49.7 14 49.7 15 51.0 15 50.9 15 50.9 16 52.3 16 52.3 16 52.3 17 53.7 17 53.5 17 53.5 18 55.6 18 55.4 18 55.4 19 57.0 19 57.1 19 57.1 20 58.7 20 58.7 20 58.7 21 60.7 21 60.7 21 60.7
22 61.7 22 61.6 22 61.6 Table 5.7 Mean length and observed length at age of L. johnii (Male) during three year 2005-2007.
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Age Mean Length Age Mean Length Age Mean Length (years) (cm) (years) (cm) (years) (cm) 2005 N=622 2006 N=525 2007 N=482
0.5 10.5 0.5 10.6 0.5 10.6 1 12.8 1 12.8 1 12.7 1.5 15.3 1.5 15.8 1.5 15.7 2 17.2 2 17.0 2 17.0 2.5 19.6 2.5 19.6 2.5 19.6 3 21.2 3 21.2 3 21.1 3.5 23.5 3.5 23.5 3.5 23.5 4 25.5 4 25.6 4 25.6 4.5 28.4 4.5 28.4 4.5 28.3 5 29.9 5 29.9 5 29.9 5.5 32.3 5.5 32.5 5.5 32.5 6 34.2 6 34.3 6 34.3 6.5 36.2 6.5 36.3 6.5 36.3 7 38.4 7 38.6 7 38.6 8 40.7 8 40.7 8 40.7 9 42.2 9 42.3 9 42.3 10 42.7 10 42.5 10 42.4 11 44.2 11 44 11 43.9 12 45.8 12 45.8 12 45.8 13 48.8 13 48.8 13 48.8 14 49.9 14 49.7 14 49.9 15 51.2 15 50.9 15 51.0 16 52.4 16 52.3 16 52.3 17 54.2 17 53.5 17 54.1 18 55.4 18 55.4 18 55.2 19 57.1 19 57.1 19 57.1 20 58.9 20 58.7 20 58.8 21 60.8 21 60.7 21 60.8 Table 5.8. Mean length and observed length at age of L .johnii (Female) during three year 2005-2007.
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5.13. Estimation of Population dynamics Parameters
In present study vide rage of size classes of L. johnii during the study period. The size frequency data of three years was used from January 2005 to December 2007 as input routines of FiSAT II to estimate the parameters (e.g., L¥, K, C, M, Z, etc.) and predict yield or stock-related attributes given certain fishing scenarios, individually by sex (male and female) and mixed population yearly basis and whole data of length frequency data of Lutjanus johnii during three years (2005-2007).
5.13.1. Analysis of population dynamics parameters by length frequency data of Lutjanus johnii whole data 2005 through Growth performance estimation by FiSAT II version 2.2.1.
The length frequency we observed the data of L .johnii was varied from 5.cm to 75cm TL and maximum age estimated from of whole data of Lutjanus johnii (combined) 2005 was 22 years, The data was fitted to Von Bertalanffy growth for male, female and mixed (all individuals) on yearly basis for the parameters of Von Bertalanffy equation L∞, K and t0 estimated by the VONBIT software (Stamatopoulos, 2005). The observed extreme length and predicted extreme length (L max) were estimated through ELEFAN 1 to estimate the values of L∞ and K for obtain the VBGF growth curve Figure. 5.24. The length frequency data was analyzed by using FAO ICLARM FiSAT software and best value of growth constant K estimated was 0.064 and L∞ was 79.611 and the calculated value of growth performance index (ø) of Lutjanus johnii was for the year 2005 during present investigation was 2.608.
Figure 5.24. Length frequency distribution fitted Von Bertalanffy growth curve (2005) Lutjanus johnii (all individuals) 2005.
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5.13.1.1. ELEFAN 1
The values of whole data of Lutjanus johnii (mixed) 2005 L∞ and K were estimated by ELEFAN 1 through length frequency data and growth curve of best fit was obtained by ELEFAN 1, which was L∞:79.61 and K: 0.120.Figure 5.25.
5.13.1.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of L∞ 79.611 and K 0.100, Figure 5.26.
Figure 5.25 Estimation of K for intermedius Figure 5.26 Estimation of K by emploing by emploing ELEFAN-1 of Lutjanus johnii Shepherd’s method for Lutjanus johnii (all (all indviduals) 2005. individuals) 2005.
5.13.1.3. Powell-Wetherall plot
Through this method values of L∞ and Z/k were stimulated through a sample representing a steady state population by pooling a time series of length frequency data with constant size class, Figure 5.27
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Figure 5.27 Powell – Wetherall plot from length frequency data of L. johnii (all individuals) 2005
5.13.1.4. Analysis of Growth Increment of Lutjanus johnii (All individuals) 2005.
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data.
5.13.1.4.1 Gulland and Holt plot Preliminary growth parameters were estimated by growth increment data , which based under VBGF growth rate decline linearly with length reached zero at L∞ and residuals of plot were used for inferences on seasonality of growth, in present study values of L∞ ,79.611 and K 0.035 were estimated. Figure 5.28.
Figure 5.28. Gulland and Holt Plot. for Figure 5.29. Munro’s plot based on (Munro all individuals data of L. johnii 2005 1982) for all individuals data of L johnii 2005
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5.13.1.4.2 Munro’s plot
Munro’s plot is based on Munro (1982) by use of growth increment data to estimate L∞ 78.610 and K, 0.213, Figure 5.29.
5.13.1.5. Mortality estimation
In present study several routines of this program were use for estimation of mortality .i.e. Total mortality (Z) from steady state length converted catch curve and natural mortality (M) represent the steady state population. 5.13.1.5.1. Total mortality (Z)
5.13.1.5.1.1. Length converted catch curves Length converted catch curve for Lutjanus johnii all individuals (unsex, male and female) for the year 2005 graph was plotted by length frequency data with constant size class and the estimated values were obtained as Z=4.54;M(at 26 ºC) = 0.22; F=4.32; E=0.95.Figure 5.30
5.13.1.5.1.2. Jones / Von Zalinge plot In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve, Figure 5.31.
Figure 5.30 Length converted catch Figure 5.31 Jones / Von Zalinge plot curve for L .johnii 2005 darkened full Lutjanus johnii dots represent the points used in calculating through least square linear regression and the open dots represent the points either not fully recruited.
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4.13.1.5.3 Total mortality (Z) from mean length
5.13.1.5.3.1. Beverton and Holt model (1956)
Beverton and Holt plot was generated by length frequency data of Lutjanus johnii (mixed) of 2005 was 0.004/year, it is a classic developed to assume that growth follows the Von Bertalanffy Growth Function (VBGF), the mortality can be represented by negative exponential decay and that L∞ is estimated from steady state population data of size frequency.
5.13.1.5.3 2. Ault and Erhardt method
Through this routine the total mortality (Z) of L. johnii whole data (mixed) 2005 was estimated 0.005/year.
5.13.1.5.4. Natural mortality (M)
In FiSAT II for estimation of natural mortality (M) two empirical and one analytical models were used.
5.13.1.5.4.1. Rikhter and Efanove’s method
This model was used to estimate the natural mortality (M) to age at which 50% of the stock reaches the age of “ massive spawning” (tmax) the estimated value was 0.064/ year.
5.13.1.5.4.2. .Pauly’s Equation
Natural mortality was estimated by Pauly’s equation was 0.21729.It were derived from independents set of estimate of M and predicted variable for most tropical species, where L∞ is available after the L∞ (cm),K (year•¹ ) and temperature (mean annual habitat temperature 26Cº).
289
5.13.1.6. Recruitment pattern
In this study plot for recruitment pattern was generated by length frequency whole data of Lutjanus johnii (mixed) 2005, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class, Figure 5.32
Figure 5.32 Recruitment pattern of Lutjanus johnii (all individuals) 2005. 5.13.1.7. Probability of capture
The Probability of capture of whole data of Lutjanus johnii (mixed) for 2005 was estimated by the length frequency data of collected specimens were collected by trawl net and gill net, the different probabilities at length size of 25 % (L25 was 19.12 , L50 was 21.83 and L75 was 24.53) by trawl net and by gill net the observed values are L(A) 18.15, L(B) 90.73, m (A) 0.50 and m (B) 2.50. Figure 5.33 (A) Probability of capture by trawl net and (B) Probability of capture by trawl net.
A B Figure 5.33. A. Probability of capture of L. johnii (all individuals) 2005 by trawl net, (B) Probability of capture 2005 by gill net.
290
5.13.1.8. Virtual Population analysis
Results of virtual population of L. johnii (mixed whole data ) 2005, shows mortality and the data was used for plot of virtual population to analyzed the population structure (Jones and Von Zalinge method, 1981), Figure. 5.34.
Figure 5.34 Length based virtual population analysis Lutjanus johnii (all individuals) 2005.
5.13.1.9. Relative yield- per Recruit and Biomass per Recruit Knife – edge selection Relative Y/R and B/R analysis, and Relative-yield-Per- recruit selection was used for Lutjanus johnii ( mixed data) 2005 for determination of the yield per recruit and biomass per recruit which calculated values of E 50 0.654 , E10 0.454 and E max 0.734.The value of M/K is 0.64, plots were generated Figure 5.35- 5.36.
Figure 5.35. Yield isopleths /Recruit Figure 5.36 Relative yield-per-recruit and analysis (Knife-edge selection) for Lutjanus biomass-per recruit for L johnii (all johnii (all individuals) 2005. individuals) 2005.
291
5.13.1.10. Maximum length estimation
The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law.
L* = a+ 1/a. p
Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion
L max= intercept of regression live with probability
Graph 5.37 Predicted maximum length of Lutjanus johnii (all individuals) 2005, based of extreme value theory (Formacion et al.,1991)
292
5.13.2. Analysis of population dynamics parameters by length frequency data of Lutjanus johnii whole data 2006 through Growth performance estimation by FiSAT II version 2.2.1
In the present study, we observed the wide size range of L.johnii in different months of the year. The size frequency data from January 2006 to December 2006 used as input in FiSAT -II and the different population parameters of L. johnii was determined by using the FAO- ICLARM Stock Assessment Tool FiSAT software Gayaniol et al. (1996).
The maximum observed age of whole data of L. johnii (combined) 2006 was 25 years, the parameters of Von Bertalanffy equation L∞, K and t0 estimated by the VONBIT software (Stamatopoulos, C. 2005).The data was fitted to Von Bertalanffy growth for male, female and mixed (all individuals) on yearly basis. Figure 5.38.
The observed extreme length and predicted extreme length (Lmax) were estimated for the whole data of L. johnii (mixed) 2006, ELEFAN 1 was used to estimate the values of L∞ and K for obtain the VBGF growth curve, the best value of growth constant K estimated by ELEFAN 1 routine was 0.065 and L∞ was 79.619.The optimized growth curve was superimposed on the restructured length frequency histograms. The calculated value of growth performance index (ø) of Lutjanus johnii for the year 2005 during present investigation was 2.615.
Figure 5.38 Length frequency and fitted Von Bertalanffy growth curve for all individuals population of L. johnii (2006).
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5.13.2.1. ELEFAN 1
The values of whole data of Lutjanus johnii (mixed) 2006 L∞ and K were estimated by ELEFAN 1 through length frequency data and growth curve of best fit was obtained by ELEFAN 1, which was L∞ 79.61 and K: 0.060, Figure 5.39.
5.13.2.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of L∞ 79.611 and K 0.100, Figure 5.40.
Figure 5.39 Estimation of K for A. Figure 5.40. Estimation of K by intermedius by emploing ELEFAN-1 of emploing Shepherd’s method for L.johnii Ljohnii (all individuals) 2005. (all individuals) 2005.
5.13.2.3. Powell-Wetherall plot
Through this method values of L∞ and Z/k were stimulated through a sample representing a steady state population by pooling a time series of length frequency data with constant size class, Figure 5.41.
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Figure 5.41. Powell –Wetherall plot for Lutjanus johnii (all individuals data) 2006
5.13.2.4. Analysis of Growth Increment of L. lutjanus (all individuals) 2006.
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data.
5.13.2.4.1 Total mortality (Z)
5.13.2.4.1.1. Length converted catch curves
Length converted catch curve for Lutjanus johnii (combined, whole data) for the year 2006 was plotted by length frequency data with constant size class and the values estimated , Z=213(C1=.953 to 13.79) and (Z=2.13; M(at 26Cº) F=1.91, E=0.90) and Length converted catch curve was plotted by length frequency data with constant size class Figure 5.42.
5.13.2.4.1.2. Jones / Von Zalinge plot In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve, Figure 5.43.
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Figure 5.42 Length converted catch Figure 5.43 Cumulative plot form of length curve for Lutjanus johnii (combined ) converted catch curve, Jones and VonZalinge 2006 darkened full dots represent the plot for Lutjanus johnii (mixed) 2006 points used in calculating through least square linear regression and the open dots represent the points either not fully recruited.
5.13.2.5. Total mortality (Z) from mean length
5.13.2.5.1. Beverton and Holt model (1956)
For this study for the data of L. johnii (combined) 2006 was used for Beverton and Holt plot and obtained the value as Z. 0.085/year ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that L is estimated from steady state population data of size frequency.
5.13.2.5.2. Ault and Erhardt method
This method is used for short live life span tropical species , therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally Z for Lutjanus johnii (male) 2005was estimated as 0.085/ year.
5.13.2.5.3. Natural mortality (M) In FiSAT II for estimation of natural mortality (M) two empirical and one analytical model were used. 296
5.13.2.5.3.1. Rikhter and Efanove’s method
In present study this model was used to estimate the natural mortality (M) to age at which 50% of the stock reaches the age of “ massive spawning” (tmass) the value of natural mortality (M) was estimated 0.067/ year.
5.13.2.5.3.2. Pauly’s Equation
Natural mortality of L. johnii (mixed data) 2006 estimated by Pauly’s equation was 0.21950/ year. It were derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ is available after the L∞ (cm), K (year•¹ ) and temperature (mean annual habitat temperature was 26ºC).
5.13.2.6. Recruitment pattern
In this study plot for recruitment pattern was generated by length frequency data of Lutjanus johnii (all individuals) 2006, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class, Figure 5.44.
Figure 5.44. Recruitment pattern of Lutjanus johnii (combined, whole data) 2006.
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5.13.2.7. Probabilities of Capture
Probability of capture was estimated by Gill net selection curve was characterized by strong left hand and right hand by normal curves, the estimated values were obtained as L(A) 16.62, L(B) 83.12, m(A) 0.50 and m(B) 0.250.Figure 5.45.
5.13.2.8. Virtual Population analysis
Virtual population analysis (VPA) was analyzed by this routine for whole data of Lutjanus johnii (2006)and generate a plot of virtual population (Jones and Von Zaling method, 1981),Figure 5.46.
Figure 5.45 Probability of capture of Figure 5.46 Virtual population analysis of Lutjanus johnii all individuals) 2006 by L. johnii (all individuals) 2006 gill net.
5.13.2.9. Relative yield Y/R and B/R analysis
Knife – edge selection Relative Y/R and B/R analysis, and Relative-yield-Per- recruit selection was used for L. johnii ( mixed data) 2005 for determination of the yield per recruit and biomass per recruit which calculated values of E 50 0.656 , E10 0.453 and E max 0.732.The value of M/K is 0.65, plots were generated Figure 5.47 and 5.48.
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Figure 5.47. Yield isopleths /Recruit Figure 5.48. Relative yield-per-recruit and analysis (Knife-edge selection) for Lutjanus E=1.0 and Lo/Lo biomass-per recruit. johnii (all individuals) 2006.
5.13.2.10. Maximum length estimation
The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a rand L* = a+ 1/a. p Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion L max= intercept of regression live with probability om variable which follows a probabilities law.
Figure 5.49 Predicted maximum length of Lutjanus johnii combined data (2006) based on extreme value theory (Formation et al., 1991). The predicted maximum length value and the 95% confidence interval is obtained from intersection of overall maximum length with line b and a, c respectively.
299
5.13.3. Analysis of population dynamics parameters by length frequency data of Lutjanus johnii whole data 2007 through Growth performance estimation by FiSAT II version 2.2.1
The maximum observed age of whole data of Lutjanus johnii (whole data) 2007 was
40 years, the parameters of Von Bertalanffy equation L∞, K and t0 estimated by the VONBIT software (Stamatopoulos, C. 2005).The data was fitted to Von Bertalanffy growth for male, female and mixed (whole data) on yearly basis (2007), Figure 5.40.
The observed extreme length and predicted extreme length (L max) were estimated for the whole data of L. johnii (mixed) 2006, ELEFAN 1 was used to estimate the values of L∞ and K for obtain the VBGF growth curve, the best value of growth constant K estimated by ELEFAN 1 routine was 0.063 and L∞ was 80.389..The optimized growth curve was superimposed on the restructured length frequency histograms. The calculated value of growth performance index (ø) of Lutjanus johnii for the year 2007 during present investigation was 2.610.
Figure 5.50. Length frequency Lutjanus johnii (all individuals) 2007and fitted Von Bertalanffy growth curve.
5.13.3.1. ELEFAN 1
Through length frequency whole data of Lutjanus johnii (mixed) 2007, growth curve of best fit was obtained values of L∞ 80.39 and k was 0.080, plot was generated by ELEFAN 1, Figure 5.51.
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5.13.3.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value , on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of L∞ 80.389 and K: 0.210, Figure 5.52.
Graph 5.51 Estimation of K for Graph 5.52 Estimation of K by emploing intermedius by emploing ELEFAN-1 of Shepherd’s method for Lutjanus johnii lutjanus johnii (all individuals) 2007. (all individuals) 2007.
5.13.3.3. Powell-Wetherall plot
Through this method values of L∞ and Z/k were stimulated through a sample representing a steady state population by pooling a time series of length frequency data with constant size class, Figure 5.53
Graph 5.53 Powell –Wetherall plot for Lutjanus johnii (all individuals) 2006
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5.13.3.4. Analysis of Growth Increment of Lutjanus johnii (all individuals data) 2007.
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data.
5.13.3.4.1. Gulland and Holt plot
Preliminary growth parameters were estimated by growth increment data, which based under VBGF growth rate decline linearly with length reached zero at L∞ and residuals of plot were used for inferences on seasonality of growth, in present study values of L∞ ,80.38 and K 0.217 were estimated plot, Figure 5.54
5.13.3.4.2. Munro’s plot
Munro’s plot is based on Munro (1982) by use of growth increment data to estimate L∞ 78.610 and K, 0.213. Figure 5.55.
Graph 5.54 Gulland and Holt Plot for Lutjanus Graph 5.55 Munro’s plot based johnii (all individuals) 2007 on(Munro 1982) for L. johnii (all individuals) 2007.
5.13.3.5. Mortality estimation
Mortality rates estimated by the routines of FiSAT II program .i.e. natural mortality (Z) from steady state sample and mean length and natural mortality (M) by two empirical equations for the whole data of Lutjanus johnii (all individuals) 2007.
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5.13.3.5.1 .Total mortality (Z) 5.13.3.5.1.1. Length converted catch curves
Length converted catch curve for Lutjanus johnii (all individuals) 2007 was plotted by length frequency data with constant size class and the values estimated , Z=2.28(C1=.5.39 to 9.96) and (Z=2.28; M(at 26ºC) =0.21; F=2.071, E=0.91) Figure 5.56.
5.13.3.5.1.2. Jones / Von Zalinge plot
In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve, Figure 5.57
Figure 5.56. Length converted catch curve Figure 5.57 Cumulative plot of length for L. johnii (all individuals) 2007 converted catch curve L. johnii (all darkened full dots represent the points individuals) 2007 used in calculating through least square linear regression and the open dots represent the points either not fully recruited.
5.13.3.6. Total mortality (Z) from mean length
5.13.3.5.6.1. Beverton and Holt model (1956)
For this study for the data of L. johnii (mixed) 2007 through Beverton and Holt plot and estimated the value of Z: 0.084/year ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative
303 exponential decay and that L is estimated from steady state population data of size frequency.
5.13.3.5.6.2. Ault and Erhardt method
Through this routine the estimated value of total mortality (Z) for Lutjanus johnii (all individuals) 2007 was 0.084/ year this method is used for short live life span tropical species , therefore this model dose not assume an infinite life span for fish stock being analyzed.
5.13.3.5.6.3. Natural mortality (M)
In FiSAT II natural mortality (M) was estimated by two empirical methods.
5.13.3.5.6.3.1. Rikhter and Efanove’s method
In present study this model was used to estimate the natural mortality (M) to age at which 50% of the stock reaches the age of “ massive spawning” (tmass) and the estimated value was 0.046/ year.
5.13.3.5.6.3.2 Pauly’s empirical equation
Natural mortality was estimated by Pauly’s empirical equation 0.21448/year. It were derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ is available after the L∞ (cm),K (year•¹) and temperature (mean annual habitat temperature was 26 ºC).
5.13.3.5.7. Recruitment pattern In this study plot for recruitment pattern was generated by length frequency data of Lutjanus johnii (mixed) 2007, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses
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/year and relative strength of each pulse by length frequency data with constant size class, Figure 5.58.
Graph 5.58 Recruitment pattern of Lutjanus johnii (all individuals)2007.
5.13.3.5.8. Probabilities of Capture
Probability of capture was estimated for the whole data of L. johnii(all individuals) 2007, through routine of gill net and the estimated values are L(A) 0.13, L(B) 0.63, m(A) 0.50 and m (B) 0.250, Figure 5.59.
Figure 5.59 Probability of capture of L. Figure 5.60. Length based virtual population johnii (all individuals) 2007 by gill net. analysis Lutjanus johnii (all individuals) 2007
5.13.3.5.9. Virtual Population analysis
Results of virtual population of Lutjanus johnii (all individuals) 2007, shows mortality and the data was used for plot of virtual population to analyzed the population structure (Jones and Von Zaling method, 1981), Figure 5.60
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5.13.3.5.10. Relative yield- per Recruit and Biomass per Recruit. Knife – edge selection Relative Y/R and B/R analysis, and Relative-yield-Per- recruit selection was used for L. johnii ( all individuals) 2007 for determination of the yield per recruit and biomass per recruit which calculated values of E 10 0.651 , E50 0.454 and E max 0.735.The value of M/K is 0.63, plots were generated , shown at Figure 5.61 and 5.62.
Figure 5.61 Yield isopleths /Recruit Figure 5.62. Relative yield-per-recruit analysis (Knife-edge selection) for and E=1.0 and L0 / biomass-per recruit. Lutjanus johnii (all individuals) 2007.
5.13.3.5.11. Maximum length estimation The maximum length estimation of lutjanus johnii for the length frequency data (mixed) 2007 as a fish in population based on assumption that the observed maximum length of a time series represented a rand L* = a+ 1/a. p Figure. 5.63. Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion L max= intercept of regression live with probability on variable which Follows a probabilities law.
Figure. 5. 63 Predicted maximum length of Lutjanus lutjanus Combined data (2007) based on extreme value theory (Formation et al., 1991).
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5.13.4. Analysis of population dynamics parameters by length frequency data of Lutjanus johnii whole data of three years (2005- 2007) through Growth performance estimation by FiSAT II version 2.2.1
The section otolith based length-at–age data seemed to used for determination of the growth ,the parameters of Von Bertalanffy equation L∞, K and t0 estimated by the VONBIT software (Stamatopoulos, C. 2005).The combined data of three years (2005- 2007) was fitted to Von Bertalanffy growth. Figure 5.64.
The Von Bertalanffy plot curve showed estimated age and coefficient of correlation of males, females and all individuals shows good relations. The values of L∞, K and t0 for males, females and all individuals are given at Table 5.9. to 5.16.
The observed extreme length and predicted extreme length (Lmass) were estimated for, ELEFAN 1 was used to estimate the values of L∞ and K for obtain the VBGF growth curve, the best value of growth constant K estimated by ELEFAN 1 routine was 0.066 and L∞ was 79.512.The optimized growth curve was superimposed on the restructured length frequency histograms. The calculated value of growth performance index (ø) of Lutjanus johnii for the year 2007 during present investigation was 2.616.
Figure 5.64 Length frequency data fitted Von Bertalanffy growth curve. L. johnii all individuals, (2005-07).
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5.13.4.1. ELEFAN 1
Through length frequency whole data of three years (2005-2007) of Lutjanus johnii values of growth parameters were estimated as L∞ 79.512 and K 0.040 growth curve of best fit was obtained by ELEFAN 1, Figure 5.65.
5.13.4.2. Shepherd’s method
This is a similar to ELEFAN 1, in present study through this a plot S value with (S max was standardized to 1) generated for rang of K value .i.e.0.560, on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of L∞ 79.51and K 0.050, Figure 5.66.
Figure 5.65 Estimation of K for A. Figure 5.66 Estimation of K by emploing intermedius by emploing ELEFAN-1 of Shepherd’s method for Lutjanusjohnii Lutjanusjohnii (2005-07). (2005-07). 5.13.4.3. Powell-Wetherall plot
Through this method values of L∞ and Z/k were stimulated through a sample representing a steady state population by pooling a time series of length frequency data with constant size class, Figure 5.67.
Figure 5.67 Powell –Wetherall plot from length frequency data of L. johnii (all individuals) 2005-2007.
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5.13.4.4.Analysis of Growth Increment of Lutjanus johnii (2005-07)
Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data.
5.13.4.4.1.Gulland and Holt plot
Preliminary growth parameters were estimated by growth increment data , which based under VBGF growth rate decline linearly with length reached zero at L∞ and residuals of plot were used for inferences on seasonality of growth, in present study values of L∞ ,79.510 and K 0.039.
5.13.4.4.2.Munro’s plot
Values of growth parameters were obtained by Munro’s plot is based on Munro (1982) were L∞ 79.411 and K, 0.036,and graph was plotted.
5.13.4.5. Mortality estimation Several programs are use for estimation of mortality rates, in present study FiSAT II was used for estimation of mortality .i.e. natural mortality (Z) from steady state sample and natural mortality (M) is represent the steady state population.
5.13.4.5.1 Total mortality (Z) 5.13.4.5.1.1 Length converted catch curves
Length converted catch curve for Lutjanus johnii for three years (2005-07) was plotted by length frequency data with constant size class estimated as Z=1.04; M at (26ºC)=1.19=F, 0-15,E=014. Figure 5.68
5.13.4.5.1.2 Jones / Von Zalinge plot In present his Jones/ Von Zalinge plot was generate cumulative plot it is an early form of length converted catch curve, Figure 5.69
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Graph 5.68. Length converted catch curve for Graph 5.69 Jones and Van Zalling plot for L .johnii whole data three years, darkened full estimation of total mortality (Z), (all dots represent the points used in calculating individuals) of L. johnii whole data three through least square linear regression and the years,2005-2007 open dots represent the points either not fully recruited, for (all individuals) whole data three years,2005-2007
5.13.4.5.2 Total mortality (Z) from mean length
5.13.4.5.2.1 Beverton and Holt model (1956)
For this study by three data length frequency of L. johnii (2005-07) through Beverton and Holt plot and estimated the value of Z: 0.596/year ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that L is estimated from steady state population data of size frequency.
5.13.4.5.2.2 Ault and Erhardt method
This method is used for short live life span tropical species , therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally Z for Lutjanus johnii (2005-07) was determined .i.e. 4.953/year.
5.13.4.5.3 Natural mortality (M)
FiSAT II for estimation of natural mortality (M) two empirical and one analytical models were used.
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5.13.4.5.3.1 Rikhter and Efanove’s method
In present study this model used to estimate the natural mortality (M) was 0.030/year, to the age at which 50% of the stock reaches the age of “ massive spawning” (tmass).
5.13.4.5.3.2 Pauly’s Empirical Equation
Natural mortality was estimated by Pauly’s equation was 1.18646/year. It were derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ is available, K (year•¹) and temperature (mean annual habitat temperature.
5.13.4.5.4 Recruitment pattern
In this study plot for recruitment pattern was generated by length frequency data of Lutjanus johnii, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class, Figure 5.70
Figure 5.70. Recruitment pettern of Lutjanus johnii (whole data) for three years.
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5.13.4.5.5 Probabilities of Capture
Probabilities of capture were studied for whole mixed three years (2005-2007) data of Lutjanus johnii was collected by trawl net and gill net for creek areas of Karachi.(Korangi creek system), through FiSAT II routine plot were obtained, Figures 5.71 and 5.72
Figure 5.71 Probability of capture of Figure 5.72 Virtual population analysis of Lutjanus johnii 2005-2007 by gill net. Lutjanus johnii, 2005-2007.
5.13.4.5.6 Virtual Population analysis
From length frequency data of total catch Lutjanus johnii (male) during the year of 2005 was used to generate the plot of virtual population to analyzed the population structure by Jones and Von Zalinge method (1981), Figure 5.73.
Figure 5.73 Length based virtual population analysis Lutjanus johnii
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5.13.4.5.7 Relative yield- per Recruit and Biomass per Recruit Knife – edge selection Relative Y/R and B/R analysis, and Relative-yield-Per- recruit is based upon Beverton and Holt model (1996), presented as Beverton and Holt model (1966), modified by Pauly and Soniano (1986), in present study plots were generated, Figure 5.74.-5.75
Figure 5.74 Yield isopleths /Recruit Figure 5.75 Relative yield-per-recruit analysis (Knife-edge selection) for and biomass-per recruit for Lutjanus Lutjanus johnii (2005-2007) johnii (2005-2007)
5.13.4.5.8. Maximum length estimation The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law. L* = a+ 1/a. p Where is P = probability (associated with the occurrence of an extreme value). 1/a = measures of dispersion L max= intercept of regression live with probability.
Figure 5.76 Predicted maximum length of Lutjanus johnii three years Combined data (2005, 2006 and 2007) based on extreme value theory (Formation et al., 1991). The predicted maximum length value and the 95% confidence interval is obtained from intersection of overall maximum length with line b and a, c respectively.
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Table 5.9 Values of L & K estimated by different routines of FiSAT II for Lutjanus johnii (all individuals) 2005
Lutjanus johnii (All individuals) 2005 ELEFAN VBGF plot Shepherds method Gulland and holt plot Munro’s method
Asymptitic length L 79.61 79.611 79.61 79.611 78.610
Growth constant (K) 0.120 0.120 0.100 0.035 0.213
Table 5.10 Values of L & K estimated by different routines of FiSAT II for Lutjanus johnii (all individuals) 2006
Lutjanus johnii (All individuals) 2006 ELEFAN VBGF plot Shepherds method Gulland and holt plot Munro’s method
79.618 79.610 79.61 79.62 78.610 Asymptotic length L
Growth constant (K) 0.065 0.100 0.0600 0.034 0.211
Table 5.11 Values of L & K estimated by different routines of Fi SAT II for Lutjanus johnii (all individuals) 2007 Lutjanus johnii (All individuals) 2007 ELEFAN VBGF plot Shepherds method Gulland and holt plot Munro’s method
Asymptotic length L 80.389 80.39 80.38 80.38 80.33
Growth constant (K) 0.063 0.080 0.210 0.217 0.211
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Table 5.12. Values of L & K estimated by different routines of Fi SAT II for Lutjanus johnii (all individuals) 2005-2007. Lutjanus johnii (All individuals) ELEFAN VBGF plot Shepherds Gulland and holt Munro’s method 2005-2007 method plot
Asymptotic length L 79.512 79.51 79.510 79.611 78.610
Growth constant (K) 0.040 0.050 0.039 0.038 0.037
Table 5.13 Estimations of total mortality (Z) by length converted catch curve routine Fi SAT II Lutjanus johnii of three years (2005-2007)
2005 Z(Y/R) Z=4.54:m(at 26C)=0.22:F=4.32:E=0.95)
2006 Z(Y/R) Z=2.13;m(at 26C)=0.21;F=2.71,E=0.91)
2007 Z(Y/R) Z=2.28 ;M (at 26C)= 0.21;F=2.17, E=0.91)
Table 5.14. Total mortality (Z) of Lutjanus johnii estimated by FiSAT II during three years (2005-2007). Beverton and Holt Method Aultand Erhandt
2005 / Year 0.004 0.004 2006 / Year 0.085 0.085 2007 / Year 0.084 0.084 2005-2007 0.596 4.953
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Table 5.15. Natural mortality (M) of Lutjanus johnii estimated by FiSAT II during three years (2005-2007). Rikhter and Efonov’s method Pauly’s method
2005 / Year 0.085 0.21729
2006 / Year 0.064 0.21950
2007 / Year 0.046 0.21448
2005-2007 0.030 1.18646
Figure 5. 16. Estimated values of Growth performance indices of Lutjanus johnii (all individuals ) 2005-2007
Year Values Growth performance indices
2005 2.608
2006 2.615
2007 2.610
All individuals (2005-2007) 2.616
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5.15. Distribution of Lutjanus lutjanus and Lutjanus johnii
In present study the during survey and personal collection based frequency data analyzed and the monthly based minimum Total length (TL), maximum total length (TL) were observed during the study period from 2005 to 2007.
In the month of January and February majority of large size specimens of L. lutjanus <14cm and L. johnii < 35cm were observed, in May first time very small juvenile up to 4.5 cm TL were observed in trash, that’s shown the both species spawn during same season in Pakistani waters.
Large specimens were found rare in number during the months of June and August may be due to monsoon season, during the September to December medium size specimens observed commonly in catch and very large specimens were found common during the months of December to February the juveniles were found near shore areas due to the presence of mangrove is a shelter for specific age as well as in adult stage they move towards the off shore waters.
Collection were made on monthly basis from main fish markets of Karachi as well as landing centers along the coast, such as Ibrahim Hiadry, Rehri, Lath Basti and Chasma Goth at Karachi District and Gharo fish market, Garho, Buharo ,Kati Bander, Kharo chhan , Jangi ser ,Jati and Tidal Link (some portion of Zero point) at District Thatta and The major part of zero point District. Badin close to the coastal belt of District. Badin and famous for two reasons (i) which lies close to the Zero line of international border (ii) Zero RD of main Drains, however at different landing centers and small fish markets of district Thatta and Badin where only Lutjanus johnii was found in maximum wt 5kg and minimum ½ kg (500gm) as well as lutjanus lutjanus was not seen at these areas, however from shore line of Karachi Lutjanus johnii and Lutjanus lutjanus both were collected from local fish markets of Karachi (Ibrahim Hiadry, Rehri), Gahro keti Bander Jangiser and Kharro Chhan (Thatta) and Zero point, Tidal link and Main fish market of Badin(District Badin) and observed that at smallest landing center (Fishing jetties) both species are found in small size Lutjanus johnii were at about 2kg (Maximum) and ¼ (250) gm minimum as well as Lutjanus lutjanus were under 100 gm only due to the reason that the fishes landed in these areas were fished by local fishermen they use small boats about 28ft (Length) by using small mesh nets (tidal trap nets) and drift net.
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During the monthly offshore from different stations of Korangi creak system .i.e Phitti Creek ,Gangyaro Creek, Khuddi Creek , Khai Kuddi Creek and Dingi Island (By drift net) in different timing by way of trawling having ½ “to 2 ¾” mash size and width about 10-35 ft and 50 ft at Tail, both species were collected in smallest size at L. johnii was 30 to 38 cm and L. lutjanus were 15 to 18 cm further it has observed that the both species of Lutjanidae , Lutjanus lutjanus and Lutjanus johnii were widely distributed in shallow water areas of Sindh coast in Juvenile stage due to their habitat as reef fishes and in large size they caught from off shore water areas of Pakistan by local fishing trawler by use of trawl net in deeper waters and majority of collection landed at Karachi fish harbor a main fish market of Karachi with associated fauna Lutjanus sp observed in Pakistan along Sindh Coast Table 5.18 and Figure.5.77-5.78.
Figure 5.77. Landing of Lutjanus sp at Karachi Fish harbor during the year 1995- 2012
Figure 5.78. Export of Lutjanus species from Pakistan during 2007-2012.
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Scientific Names FAO / English name Local Name
Lutjanus Johnii (Bloch, 1792) John’s Snapper Hira
Lutjanus argentimaculatus Mangrove Red Snapper Hira (Forskal, 1775) Lutjanus fulviflamma (Forskal,1775) Black spot Snapper Hira
Lutjanus lanulatus (Park,1792) Lunartail snapper Hira
Lutjanus malabaricus Malaba blood snapper Hira (Baloch & Schneider, 1801) Lutjanus lutjanus (Baloch,1790) Big eye snapper Snapper Hiro
Lutjanus rivulatus (Cuvier,1828) Blubberlip snapper Mayo
Lutjanus erythropterus (Baloch ,1970) Crimson Snapper Hira
Lutjanus sebae(Cuvier,1828) Emperor Hira
Lutjanus carnolabrum (Chan,1970) Tang snapper Hira
Lutjanus gibbus (Forskal, 1775) Humpbak re vsnapper Hira
Lutjanus bohar (Forsskal,1775) Two-spot red snapper Hira
Lutjanus singuineus (Cuvrier,1828) Humphead snapper Hira
Lutjanus fulvus (Schneider,1801) Black tail snapper Hira
Lutjanus bangalensis (Blaoch,1790) Bengal snapper Hira
Lutjanus kasmira (Forsskal,1775) Common bluestripe Hira snapper Lutjanus russelli (Bleeker,1849) Russell’s snapper Hira
Lutjanus vitta (Quoy & Gaimard, 1824) Brownstripe snapper Hira
Table.5.17 Lutjanus sp observed in Pakistan along Sindh Coast.
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5.15.1. Discussion
Distribution of L. lutjanus and L. johnii from Sindh Coast Pakistan.
The Pakistan situated between the 24Â ° N, 37Â ° N latitudes, 61Â ° E, and 75Â ° E longitudes, has two main coastal regions i.e. Sind coastal region and Balochistan coastal region. Figure-5.79.The Sindh coast of Pakistan having great deltaic region situated at Thatta and Badin District and Sindh coast has two main units one Karachi (North west coast and 2nd Indus Delta region (Southeast Coast) ; Hassan, (1983) and Khatoon, (2006). The Korangi Phitti Creek system found in Karachi region and has a complex network of creeks and mangroves as reported by Hassan, (1991); Maynell and Qureshi, (1992). The southeastern coastline of Pakistan having 240 Km of mangrove forest mostly consist of the Avicenna marina (Huda and Khan, 1996).
Previously many observations about Korangi Phatti creek system, mangroves ecology and diversity of fishes have been reported i.e. Meynell and Qureshi (1985 and 1993) reported the rehabilitation of Indus delta mangroves, Meynell (1995) and Khan and Aziz (2001) reported the ecology and population of mangrove flora. Tirmizi et al. (1995) reported the wave action of their areas. Khan et al. (1986) reported the diversity of fish communities and also reported the presence of A. berda in mangrove swamps. Mirza and Hassan (1983) and Hassan (1991) reported the bio ecology of this area. Some work on fish stock assessment of Arabian Sea discussed by (Meynell and Qureshi, (1992) and Meynell,(1995); Anon, (1976;1977) several comprised the check list of fish fauna of Pakistan Qureshi, (1945,1960); Jaleel and Khalil Uddin. (1972); Jaleel, (1978); Bianchi, (1985); Ahmed, (1988) ; Hussian and khatoon (2000) kidwai and Amjad (2001) reported in field Guide commercial Marine and brackish water species of Pakistan the landing of Lutjanids during 14 years (1995 to 2008) reported by Marine fisheries Department, Government of Pakistan and export form Pakistan marine fishes are being exported throughout the world and Lutjanus sp are in one of them, the Marine fisheries Department, Pakistan estimated the total export of marine fishes during last five years (2007-2012).
320
Population of Lutjanids is associated with deeper habitat and mature at 49% of their maximum length as compared to 43% for shallow water population, although effects zoo geographically evident at the P= 0.05 level of significant. L. lutjanus and L. johnii are continental shelf in habit and associated with their margin as well shallow depth in compression to insular and deeper habitat. Information regarding stock assessments dynamics, populations status and biology of a fish reported by Iqbal, (1989; 1992) and Stearn, (1976),Szedlmayer, (1994) studied distribution of Lutjanus campechanus by mark and recapture, vertical distribution found in juveniles of Lutjanids, although, Saucedo, et al (1998) reported juveniles of other species recorded in coastal waters at 20 to 40 m depth, in eastern Pacific Snapper (Lutjanus peru) and spotted rose snapper restricted up to depth 20 to 40 meter at coastal belt of Jalisco and Colina, Mexico. Mostly authors discussed two types of selection of juvenile of snappers on the basis of habitat for Indo West Pacific region.
In the present study, the monthly variation in diversity of both species observed on the environmental and seasonal changes during the boat collections Lutjanids caught with other associated fishes shown at table 5.18 and Graph 5.248 (A&B). The market survey showed that the main landing center Karachi Fish Harbour having all sizes of fishes in year around and small size fishes were caught by small scale fishermen were observed small fish market for local consumption and large specimens were observed at main fish market the Karachi Fish Harbour and Marine Fisheries Department Government of Pakistan has reported the nominal catch, landing and export of marine fishes during the up to 2012. Figure, 5.81 with special reference to Lutjanids species wise landing during 2012 reported at Table. 5.19 shown deposition of catch, species wise landing nominal catch, and export of marine fishes with special reference to Lutjanids.
In present study the monthly variation in diversity of both species may depend on the environmental and seasonal changes. The market survey showed that the main landing center Karachi Fish Harbour having all size of fishes in year around. All size boats carried their catch brought to the main landing centre Karachi Fish Harbour for auction. Figure -5.82-84.
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Figure.5.79. Coastal belt of Sind.
Figure 5.80. Deposition of fish catch (2003-2012).
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S. No Scientific Name English Name Local Size No, Name s
1. Sardinella longiceps Indian Oil Sardine Luar 12-14 cm 10
2. Hilsa kelle Kelee Shad Palli 12-16 cm 15
3. Tenualosa ilisha Hilsa Shad Palla 10-24 cm 14
4. Nemotolosa nususa Long ray bony Daddi.Palli 08-14 cm 6 bream
5. Scrobeoides Talang Queen Fish Aal 15-22 cm 8 commersonianus)
6. Lutjanus Mangrove Red Hira 12-16 cm 4 argentimaculatus Snapper
7. *Lutjanus johnii John’s Snapper Hira 20-26 cm 5
8. Sillago sihama Lady Fish Bhumbor 10-14 cm 14
9. Pomadasys argenteus Lined silver grunter Dhotter 10-16 cm 4
10. Terapon jarbua Crescent perch Ginghra 6-18 cm 4
11. *Lutjanus lutjanus Big Eye Snapper Hira 4-9 cm 2
Table .5.18 Species composition of fishes caught from Khuddi creek (Korangi) Karachi during boat collection.
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Graph 5.249. A. Specimens observed during the Boat collection from Gangyaro creek. B. Specimens observed during the Boat collection from Khuddi Creek (Korangi) Karachi.
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A
B
C
Figuure. 5.81 (A) Nominal catch of finfish and shell fish (2001-2012) (B) Specieswise Landing at Karachi harbour during 2012,(C) Total export of fish during, 2001-2012.
325
SPECIES TOTAL IN METRIC TONS SMALL PELAGICS 40,496 Shads 266 Sardinellas 12,156 Misc. Clupeoids 11,346 Thryssas 4,750 Scads 1,324 Indian Mackerel 10,654 DEMERSALS 89,178 Sharks 2,312 Guitarfishes 254 Rays 4,012 Wolf Herrings 561 Bombay Duck 45 Catfish 14,563 Eels 1,752 Threadfin Breams 3,011 Barracudas 4,013 Mullets 6,015 Groupers 6,879 Croakers 7,123 Silver Whitings 401 Cobia 1,002 Queenfish 3,432 Travellies 1,623 *Snappers 1,532 Grunts 451 Emperors 202 Threadfin 204 Misc. Sea Breams 1,855 King Soldier bream 1,350 Ribbonfish 7,065 White Pomferts 1,734 Soles 2,231 Black Pomfrets 2,310 Others 13,246 LARGE PELAGICS 37,615 Dolphinfish 804 Spanish Mackerels 4,069 Tunas 31,211 Sailfish 1,531
Table 5.19 Species wise landing of fish species at Karachi Fish Harbour with special reference to Lutjanus species during 2012.
326
A
B
C
Figure 5.82. (A) Collection by trawl net in Korangi Creak August (2006),(B) Tidal effected area of Korangi Creak Channel, Karachi, near khuddi creek, (C) Ibrahim Haidry, Karachi.
327
A
B
C
Figure. 5.83. (A) Main fish market of Ibrahim Haidry (B) L. lutjanus at Karachi Fish Harbor (December 2007) (C) at Ibrahim Hiadery (Fish Market Karachi) November 2007.
328
A
B
Figure. 5.84. A & B L. johnii at Karachi fish Harbor (November 2007). C Mouth of Phitti creek channal.
329
6. Discussion
6.1 Lutjanus lutjanus
6.1.1 Gonadal Maturation
In present study the gonads of L. lutjanus was observed by both techniques macroscopic and microscopic. The gonads show typical developmental stages in multiple spawning, during observations different development stages and changes in gonads were examined. As studied by Franch et al (2006) and Thresher (1984) the L. lutjanus is a gonochoristic species, The examination of sex by age also revealed a variable pattern in male to female ratios as studied by Heupel et al (2009) in gonads of juveniles the testicular part shows they are whitish in color and thin while ovary were reddish in color and the size of fish increases, size of gonads also increased and medio-dorsal side of gonad contained translucent yellowish orange ovarian zone similar findings has been 1:1 sex ratios observed in present study populations Franch et al (2006) and Simone et al (2010).
The examination of gonadal maturation showed that the juvenile increasing size transformed into functional during spawning season. In present study the females were considered responsible for spawning and testes studied less than female, the cellular changes in spermatogenesis were not marked as in Oogenesis and it is more difficult to establish the stage of reproductive cycle as similar to the other species of the family Lutjanidae as discussed by Siveria et al.(1995), the spawning season of Lutjanids discussed by Kritzer (2004), Grandcourt et al. (2006), Arara and Ntiba(1997), Rojas (1987), Sadovy (1996) and Rojas et al. (2009), as observed in L. analis.
Histological analyses females in early maturation stages up to resting and if male stage III and VI were observed and several oocytes developmental stages has been found in a single female’s gonad (early maturation, ripe and spent) indicates a gonadal development of multiple spawning sp as reported by Simone, et al (2010) in Lutjanus analis, In this mode of spawning several portions of oocytes develop successive maturation stages and are spawning season. The observations are similar as previously
330 reported that the many Lutjanids species are multiple spawner such as L. peru (Santamaria-Miranda et al. 2003), L. syngaris (Sousa Jr. et al. 2008) and L fulviflamma (Kaunda-Arara & Nitaba 1997), this mode of spawning allow that the female of a same population, which reproduce in the same period, as reported by Nikolsky (1963).
The 50% sexual maturity (l50%) was also determined separately, the L. lutjanus attained at 14.5 cm TL. The logistic curve for both sex (combined) shows best fit to proportional mature data r² and the coefficient of correlation shown strong correlation between total length (cm) and sexual maturity of combined data. Sousa Jr. et al (2008) and Kaunda-Arara & Nitaba (1997).
6.1.2 Spawning and estimation of fecundity
In present study the ovaries stage III of L. lutjanus were found during the months of June and July, frequency of mature female were in October rises up to November and December, few female with opaque granules oocytess and post follicles (POF) were studied and spent ovaries in dark brown color were observed in November. Fully matured females with stages VI and VII were observed in the months of January and February, and mostly spent observed in March as well as in the months of April and May immature/ stages I & II were observed.
The rise and decline of Gonadosomatic index (GSI) values and gonadal maturation verified by spawning observed from the months of November to March. The peak spawning observed in December to February when 95% specimens were matured the growth is of particular significance as discussed by Roff (1983) the fecundity is an increasing function of body size and energy channeled into the gonads reduces somatic growth and affects future fecundity.
The plot of ova diameter estimation shows bimodal. The smaller size skewed left and large size of the ova skewed right side of the plot, which indicated that L.lutjanus is a multiple spawner as earlier reported in different species of such as L. peru ,L.
331 syngaris and L fulviflamma by Santamaria-Miranda et al (2003), Sousa Jr. et al (2008) and Arara & Nitaba (1997)
The large oocytes in stage V and VI ovaries were used to estimate the potential annual fecundity as previously estimated by Nitaba (1997). The estimation of fecundity is slightly more than the previously reported by Roff (1983) but less then Nitaba (1997).
6.1.3 Scale and otolith
In case of Scale, the number of circuli around the scale of fish provides unreliable estimation of age but the number of annuli in otolith generally offers an accurate evaluation for aging fish (Beamish & McFarlane,1983; Campana,2001). Casselman (1987) reported that the scales circuli in trout (Salvelinus namaycush) not formed on entire scales it is difficult to find the true and false circuli. In the present, we observed species, L. lutjanus and L. johnii have the pattern of circuli formation yield over estimate of the age as well as the growth zones delineated on otoliths are more reliable (Campana, 2001).
6.1.4 Marginal increment
The results of marginal incensement (MI) were obtained and measured from sectioned otolith by observation of one opaque zone found at otolith by building in software scale in millimeter unit that’s shown one opaque growth zone was delineated on otolith during November to February. The mean values of marginal increments were plotted against months, showed the value of mean monthly increments was starting to rise in month of October to March and peak is observed in January when maximum values were 1 mm observed and decline was .08- 0.25 mm observed from April to August. The growth zone formation is a corresponding to the spawning season, during warm season months, the water temperature ranged between 12.5 ºC to 14.5 ºC and during the colder season suggested that the energy was invested in developing gonads so the somatic weight decrease and as temperatures rise the Lutjanids fast down their feeding activities. It is also reported that the one opaque zone delineated in a year as
332 reported previously by Buxton, (1992) ;Buxton and Clark (1989) and Chale - Matsau, et al (2001).
6.1.5 Length at age analysis
The von Bertalanffy growth function curve (VBGF) was use for estimation length at age data was to generate plots and parameters were recorded separately for male, female and all individuals on yearly basis. Previously this growth equation was used to describe growth of many members of family Lutjanidae by Andrew McDougall, 2004. The peak spawning period of individual fish was believed to correspond with their birth date and it was used to determine the age of fish (Hay, 2005 and Dumas, et al., 2004) The growth equation parameters obtained by VONBIT software by using non linear regression shown in table: 4.12 to 4.20. and 4.26.
The values of growth parameter are close to previously reported results but the difference was found due to environmental differences the age of Lutjanus lutjanus was reported as 14 years and similarly in the present study the sectioned otolith based estimate the age was 14 years.
Newman 1996 reported that the comparisons of growth parameters and longevities in among Lutjanids species are difficult because age estimates are based on different methods and the growth rate is dependent on an accurate estimation of longevity. The mean age of species of the genus Lutjanus when using sectioned otoliths is 21.5 years, which is nearly double the age estimate of 11.5 years from studies using scales (Druzhinin and Filatova 1980), and the difference is even greater with other techniques. Lai & Liu 1974, Edwards 1985 and Liu & Yeh1991 and reported if using vertebrae, the mean age becomes 8.7 years 6.8 years with whole otoliths (McPherson and Squire 1992), and just 5.8 years when using length frequency analysis (Ambak 1987). Aiken (2001) compared two different ageing techniques and found that the estimates of longevity for L. synagris was 14 years when using sectioned otoliths but only 6 years using whole otoliths. The higher estimates of longevity and their
333 respective low natural mortality rates suggest that snappers are more vulnerable to over- fishing than other species with shorter life spans and higher natural mortalities (Newman, et al. 2000); however, some scientists also suggest that longevities of more than 20 years actually benefit a species by ensuring a relatively long reproductive span and minimizing the risk that prolonged periods of unfavorable environmental conditions will lead to the loss of a stock (King and McFarlane 2003) as observed in present study. 6.1.6 Population dynamics parameters
FAO-ICLARM Stock Assessment Tool (FiSAT) analyzed the length frequency data of Lutjanus lutjanus and estimated the different population parameters. The length frequency data contained all smapled fishes used in Faben’s method and Gulland-Holt method and values were obtained as values of L ,30.00 and K 0.154 but in otolith based technique selective data for individuals were used.
The Growth parameters of Von Bertalanffy growth function (VBGF) estimated by growth increment data The values of L∞ for Lutjanus lutjanus was 38.32 and value of K was 0.370 /year where the values of L∞ were lower and values of K were higher than the reported by Edward (1985) for Lutjanus malabaricus L∞ 707cm and K
0.168/year , L∞ 59.1 and K 0.219/year for Pristipomoides multidens and L∞51.5cm and K 0.254/year from Australia In present study values of K were estimated for males 0.560 /year (2005),0.310/year (2006),0.390/year (2007) for females value of K were 0.370/year (2005), 0.520/year (2006) and 0.390/year (2007) and for combined data ( male, female and unsex) as 0.530 (2005), 0.540(2006) and 0.370 (2007). Munro’s method used for estimation of growth parameters and values were obtained for L. lutjanus (female) 2006, were obtained by Munro’s plot is based on Munro
(1982) were L 30.00 and K, 0.802
Several programs are use for estimation of mortality rates, in present study FiSAT II was used for estimation of mortality .i.e. total mortality (Z) from steady state sample and length converted catch curve, natural mortality (M) by the steady state population.
334
The Total mortality for Lutjanus lutjanus (all individuals) by Length converted catch curve for the year 2007 and Z/yr were obtained as (Z/yr) 0.87 (C:I-2.09 to 3.50) for Z=0.87;M at (26ºC)=0.85:F=0.14, E0.20, and Length converted catch curve was plotted by length frequency data with constant size class. Jones and Van Zalling plot used for estimation of total mortality (Z) and generated cumulative plot as an early form of length converted catch curve. By Beverton and Holt model (1956) In present study Beverton and Holt plot was used for estimation of (Z) the whole data of L. lutjanus (all individual) 2005-2007 and the obtained value of Z: 0.389/year ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that Linf is estimated from steady state population data of size frequency. Ault and Erhardt method through this method (Z) estimated for L. lutjanus (all individuals) whole data 2005-2007 generally this method is used for short live life span tropical species, therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally estimated Z was 0.420/year.
The Natural mortality (M) For estimation of natural mortality (M) two empirical and one analytical model were used in FiSAT II. Rikhter and Efanove’s method model was used to estimate the natural mortality (M) and estimated (M) was 0.109/year at
50% of the stock reaches the age of “ massive spawning” (tmass).Pauly’s Equation used for natural mortality estimated by Pauly’s was 0.48121/year, derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L is available after the L (cm),K (year•¹) and temperature (mean annual habitat temperature (Cº).
The growth parameters L∞ and K have an effect on each other. They are inversely proportional to each other (Knight, 1968), so the high value estimate of L∞ is resulted in the less value of K. The parameter to and K has a direct relationship and K shows the curve of von Bertalanffy. The age between 12 years to 15 years were common in members of Family Lutjanidae.
Recruitment pattern and Probabilities of Capture length frequency data of L. lutjanus (all individuals) 2005-2007 was used for estimation of probabilities of capture by the gill net option and curve was obtained. The different probabilities at length size of
25% (L25 was 2.60 cm and L50 3.66cm and L75 4.48cm. The obtaining values showed
335 the high catching probability of the small sized individuals by the gill net fishing. The virtual Population analysis showed maximum fishing mortality, estimated from length frequency data of total catch L. lutjanus (all individuals) during the year of 2005- 2007 was used to generate the plot of virtual population to analyze the population structure.
The Knife –edge selection of FiSAT-II was used to determined the yield per recruit and biomass per recruit which calculated the values of E10= 0.359, E50= 0.285 and
Emax: 0.431. The obtaining value of M/K is 0.900. The result showed that the level of E is lower as compared to (Y/R). The maximum sustainable yield (MSY) can be attain with an exploitation rate of 1.0, present exploitation rate ratio was 0.507. The present obtaining results indicated that the L. lutjanus is not exploited above the maximum sustainable yield in present study plots were generated the maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variable which follows a probabilities law.
In present study through population dynamics study it was observed the small size fished by tidal trap nets in creek areas and in maximum size L. lutjanus were captured by trawl nets in off shore waters and found only main fish markets of the province, comparative statements for the whole data of three years (2005-2007) study of L. lutjanus by sex (Male and Female) and all individuals. The distribution and life history of many Lutjanids were little known about characteristics reported by Newman, et al. (1996; Arara and Ntiba (1997); Marriott, et al (2007) Although research has covered much of the family’s range, including Mexico, Kenya, United state, Great Barrier Reef and Indian Ocean, (Manickchand et al., 1996; Amezcua, et al.,2006; Meyer, 1990; Shimose and Tachihara 2006., Newman et al. 1996, 2000; Marriott, et al. 2007. Grandcourt, et al., 2006) Many species remain unstudied and comparisons between species are limited. The little data that does exist suggests that some Lutjanids like Lutjanus johnii are long-lived life span over thirty years (Newman, et al.1996 and Marriott et al. 2007).
336
Status Location L∞ cm K /yr Ø
Combined Pakistan 79.51 TL 0.066 2.61 (male, female and unsex) (2005 2007) Present study
Male 2005 24.68TL 0.560 1.989 2006 39.38TL 0.310 1.991 2007 38.33TL 0.390 2.517 Female 2005 38.33TL 0.370 2.533 2006 38.33TL 0.520 2.130 2007 38.33TL 0.390 2.160
Combined 2005 39.38TL 0.530 2.233 (male, female and 2006 39.37TL 0.540 2.241 unsex) 2007 38.32TL 0.370 2.258
Previously reported
Stephan John 1995 GBR Australia 20.0FL 0.265
Philippine Parbilao 66.7 NG 0.13 2.76 mangrove Indonesia Barito Estuary 72.4 TL 0.38 3.29 South Kalimantan India Adman Sea 96.1 FL 0.12 3.03
Fish Base ------72.4 TL 0.40 3.29
Table. 4.26. Comparison of present study with previously reported results for L. lutjanus
337
6.2. Lutjanus johnii 6.2.1 Gonadal Maturation
In the present study the different developmental stages of and changes occurred in gonads were first examined by macroscopically and then verified by histological technique as previously reported in several species by Abu-Hakima, (1984), Pollock, (1985) and Tobin (1998) the testicular part shows whitish in color and thin while, the ovary was dark reddish brown in color, when size of fish increases the size of gonads also increased and medio-dorsal side of gonad contained translucent yellowish dark orange ovarian zone the development of gonad does not show any difference.
The macroscopic observation shows the juvenile shows anteriorly whitish the scheme was used for macroscopic analysis of gonadal development by Tobin (1998) as Emata et al (1999) reported that the fish get large the whitish zone become dominated and ovary was dark in color, As studied by (Thresher 1984) and Franch, et al (2006) the L. johnii is a gonochoristic species, and the examination of sex by age also revealed a variable pattern in male to female ratios as reported by Heupel, et al (2009) the size of gonads also increased and medio-dorsal side of gonad contained translucent yellowish orange ovarian zone. The 1:1 sex ratios observed in present study populations as reported previously by Franch, et al (2006) and Simone, et al (2010).
The examination shown the juvenile increasing size transformed into functional during spawning season. In present study females were considered responsible for spawning and testes studied less than female, the cellular changes in spermatogenesis were not marked as in Oogenesis and it is more difficult to establish the stage of reproductive cycle as similar to the other species of the family Lutjanidae as discussed by Silveria et al.(1995), the spawning season of Lutjanids discussed by (Kritzer 2004, Grandcourt et al. 2006), (Arara and Ntiba1997; Rojas, 1987; Sadovy, 1996, Rojas, et al., 2009) as observed in Lutjanus analis.
The histological analyses of females in early maturation stages up to resting and in male stage III and VI were observed and several oocytes developmental stages has been found in a single female’s gonad (early maturation, ripe and spent) that’s 338 indicates a gonadal development of multiple spawning sp as reported by Simone, et al (2010) in Lutjanus analis,
The observations are similar as previously reported that the many Lutjanids species are multiple spawner such as L. peru (Santamaria-Miranda et al. 2003), L. syngaris (Sousa Jr. et al., 2008) and L fulviflamma (Arara & Nitaba, 1997) this mode of spawning allow that the female of a same population, which reproduce in the same period, as reported by Nikolsky (1963).
The 50% sexual maturity (l50%) was also determined separately, the male of L. johnii attained at 47cm TL and female specimens of Lutjanus johnii 57cm TL. The logistic curve for both sex (combined) shows best fit to proportional mature data r² and the coefficient of correlation shown strong correlation between total length (cm) and sexual maturity of combined data as discussed by Sousa Jr. et al (2008) and Arara & Nitaba (1997).
6.2.2 Spawning and estimation of fecundity
In present study the ovaries stage III of L. johnii were found during the months of June and July, frequency of mature female were in October rises up to November and December, few female with opaque granules oocytess and post follicles (POF) were studied and spent ovaries in dark brown color were observed in November. Fully matured females with stages VI and VII were observed in the months of January and February, and mostly spent observed in March as well as in the months of April and May immature/ stages I & II were observed.
The rise and decline of Gonadosomatic index (GSI) values and gonadal maturation verified by spawning observed from the months of November to March. The peak spawning observed in December to February when 90% specimens were matured the growth is of particular significance as discussed by Roff (1983) the fecundity is an increasing function of body size and energy channeled into the gonads reduces somatic growth and affects future fecundity.
339
The plot of ova diameter estimation shows bimodal. The smaller size skewed left and large size of the ova skewed right side of the plot, which indicated that L.johnii is a multiple spawner as earlier reported in different species of such as L. peru ,L. syngaris and L fulviflamma by Santamaria-Miranda et al (2003), Sousa Jr. et al (2008) and Arara & Nitaba (1997)
The large oocytes in stage V and VI ovaries were used to estimate the potential annual fecundity as previously estimated by Nitaba (1997). The estimation of fecundity is slightly more than the previously reported by Roff (1983) but less then Nitaba (1997).
In present study different stages of maturation were observed, stage II ovaries were found first during the months of June and July, frequency of mature female were in September rises up to November and December, few female with opaque granules oocytes and post follicles (POF) were studied and spent ovaries were found in November .i.e. dark reddish / brown in color.
Fully matured females with stages VI and VII were observed in the months of September and October and mostly spent observed in January and March and in e months of April and May immature/ stages I & II were observed. The monthly variation in maturity stages were observed.
The mean age at maturity can vary considerable among populations of the same species due to environmental factors such as at maturity for the American shad (Alosa sapidissima) increases with latitude from Florida to Canada by Leggett and Carscadden, (1978) Another factor affecting maturity within species is the social interaction of the sexes. age at maturity and fecundity generally increase with adult body size but since growth usually slows down with age the age specific fecundity also slow down (Roff 1992).
In present study it was observed that during the peak spawning season two fully matured females were obtained for this study from every year they have stage-VI., and it was observed that the Lutjanus johnii is a multiple spawned, hydrate oocytes were visible through ovarian wall. The plot of ova diameter estimation shows bimodal. The smaller size skewed left and large size of the ova skewed right side of 340 the plot, which indicated that Lutjanus johnii is a multiple spawner, the large oocytes in stage V and VI ovaries were used to estimate the potential annual fecundity as previously estimated.
6.2.3 Scale and otolith
In case of Scale, the number of circuli around the scale of fish provides unreliable estimation of age but the number of annuli in otolith generally offers an accurate evaluation for aging fish discussed by Beamish & McFarlane,(1983); Campana,(2001). Casselman (1987) reported that the scales circuli in trout (Salvelinus namaycush) not formed on entire scales it is difficult to find the true and false circuli. In the present, we observed species, L. lutjanus and L. johnii have the pattern of circuli formation yield over estimate of the age as well as the growth zones delineated on otoliths are more reliable (Campana, 2001).
In present study the circuli observed around the scales of fish provides unreliable estimation of age fish, but the quantity of annuli in otoliths offers an exact check for ageing fish (Beamish and McFarlane, 1987), reported that the scales circuli in trout (Salvelinus namaycush) was not formed on entire scales; it is difficult to find the true and false circuli as studied by Casselman, (1987).
6.2.4 Marginal increment analysis (MI)
In present study the results of marginal incremental values showed that the one opaque growth zone was delineated on otoliths during, mean monthly incensement (MI) on section otoliths were measured by building in software scale in millimeter unit. The mean values of marginal increments were plotted against each months, plot showed that the value of mean monthly increments was starting to rise in the month of May to July and peak observed in September when maximum values were 1 mm observed and decline was .08- 0.25 mm observed from December to April. The rise and decline of mean monthly marginal incremental values verified that the only one opaque growth zone formed in a year, November to February. During these months the water temperature is between 12.5 ºC to 14.5 ºC. Kraljevic,1995 reported that during colder months the bream ceases their growth but Chaoui, et al.,2006 suggested
341 that the energy was invested in developing gonads so the somatic weight decrease and as temperatures rise the bream slow down their feeding activities, both factors affect the growth rate.
6.2.5 Length at age analysis
Length frequency data for estimation of length at age was used as input to generate the von Bertalanffy growth function curve (VBGF), and parameters were recorded separately for male, female and all individuals separately on yearly basis and different growth zones were observed. The peak spawning period of individual fish was believed to correspond with their birth date and it was used to determine the age of fish.
Growth parameters L∞ varies, K and t0 have been estimated at 75.4 cm for Lutjanus johnii. The fishes appeared to have an approximate life span of Lutjanus johnii 22 years. The mean annual instantaneous rates of total mortality, natural mortality and fishing mortality were also studied for the year 2005-2007 and from the values of mortality it seems that the fishing intensity on the stock of Lutjanus johnii was much higher than what should have been the optimum.
The section otolith based length-at–age data seemed to used for determination of the growth ,the parameters of Von Bertalanffy equation L∞, K and t0 estimated by the VONBIT software (Stamatopoulos, C.1989).The combined data of three years (2005- 2007) was fitted to Von Bertalanffy growth.
In present study initially ELEFAN-1 was used to estimate the values of L∞ and K for obtain the VBGF growth curve, the best value of growth constant K estimated and the values routine were 0.066 and L∞ was 79.512. The calculated value of growth performance index (ø) of Lutjanus johnii for the year 2007 during present investigation was 2.616. and Shepherd’s method a similar to ELEFAN 1, was used to a plot S value with (Smax was standardized t0 1) generated for rang of K value .i.e.0.560, on a log scale, and 10 best scores were highlighter , this is enabling selection of the “best” combination of L∞ 79.51and K 0.050. Through Powell- Wetherall plot method values of L∞ and Z/k were stimulated through a sample
342 representing a steady state population by pooling a time series of length frequency data with constant size class. Table-5.17.
Status Country/Location L∞ K /yr Ø Combined Pakistan 79.51TL 0.150 2.616 (male, female and unsex) (2005-2007) Present study Combined 79.61TL 0.120 2.608 (male, female and unsex) 2005
Combined 79.610TL 0.100 2.615 (male, female and unsex) 2006 Combined 80.39 0.80 2.610 (male, female and unsex) 2007 Previously reported Stephan John GBR Australia 91.6FL 0.116 (1995)
Table. 5.20 Comparison of present study with previously reported results for Lutjanus johnii.
Gulland and Holt plot a preliminary growth parameters were estimated by growth increment data , which based under VBGF growth rate decline linearly with length reached zero at L∞ and residuals of plot were used for inferences on seasonality of growth, in present study values of L∞ ,79.510 and K 0.039, the values of growth parameters were obtained by Munro’s plot is based on Munro (1982) were L∞ 79.411 and K, 0.036,and graph was plotted. In present study Several programs are use for estimation of mortality rates, in present study FiSAT II was used for estimation of mortality .i.e. natural mortality (Z) from steady state sample and natural mortality (M) is represent the steady state population.
343
The Length converted catch curve for Lutjanus johnii for three years (2005-07) was plotted by length frequency data with constant size class estimated as Z=1.04; M at (26ºC)=1.19=F, 0-15,E=014.
The total mortality (Z) estimated by three data length frequency of L. johnii (2005- 07) through Beverton and Holt plot and estimated the value of Z: 0.596/year ,it is a classic developed to assume that growth from mean length was obtained the mortality can be represented by negative exponential decay and that L is estimated from steady state population data of size frequency. Ault and Erhardt method was used for short live life span tropical species , therefore this model dose not assume an infinite life span for fish stock being analyzed, however in present study experimentally Z for Lutjanus johnii (2005-07) was determined .i.e. 4.953/year.
For estimation of natural mortality (M) two empirical and one analytical models were used. Rikhter and Efanove’s method this model used to estimate the natural mortality (M) was 0.030/year, to the age at which 50% of the stock reaches the age of “ massive spawning” (tmass). Natural mortality was estimated by Pauly’s equation was 1.18/year,.It were derived from 175 independents set of estimate of M and predicted variable for most tropical species, where L∞ is available, K (year•¹) and temperature (mean annual habitat temperature estimated mortality were lower as estimated by Khan (1987) i.e. 2.70, 0.59 and 2.11 for Lutjanus johnii from Bangladesh.
The recruitment pattern was generated by length frequency data of Lutjanus johnii, through this reconstructed routine the recruitment pulses from a time series of length frequency data to determine the number of pulses /year and relative strength of each pulse by length frequency data with constant size class and Probabilities of capture were studied for whole mixed three years (2005-2007) data of Lutjanus johnii was collected by trawl net and gill net for creek areas of Karachi.
In present study the virtual Population analysis From length frequency data of total catch Lutjanus johnii (male) during the year of 2005 was used to generate the plot of virtual population to analyzed the population structure by Jones and Von Zalinge method (1981).
344
The Knife – edge selection Relative Y/R and B/R analysis, and Relative-yield-Per- recruit is based upon Beverton and Holt model (1996), presented as Beverton and Holt model (1966), modified by Pauly and Soriano (1986). The maximum length estimation of a fish in population based on assumption that the observed maximum length of a time series represented a random variables the predicted maximum length of Lutjanus johnii three years Combined data (2005,2006 and 2007) based on extreme value theory (Formacion. et al., 1991). The predicted maximum length value and the 95% confidence interval obtained.
Andrade (2003) discussed the life- history variables scientific management of the snapper fisheries as the asymptotic length or the highly correlated length at maturity is necessary to determine the maximum possible yield (expressed as optimum harvest length) of a particular species. Growth rate data are essential to determine whether a species is exploitable or not, to describe the population age structure, or to predict growth responses to environmental changes. (Brothers 1979) reported that the half of the species of snappers lack any kind of growth or age estimate and many of the species that do have age estimates have not used sectioned otolith readings and have not been validated. The Mortality rate is another important variable and is basic for fishery analysis using population dynamics models. Newman et al.1996 discussed and considered the smaller species of snappers have considerably higher natural mortality rates and several populations are either unexploited or are utilized by local artisanal fishermen usually making low impact on the mortality attributed to fishing activities.
Finally in our findings indicate that current databases to support policies for the management of many snapper fisheries are highly inadequate.
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7. Conclusion
Both species Lutjanus lutjanus and Lutjanus johnii belong to family Lutjanidae have similar distribution and same habitat. Present work has consisted on aspects of age and growth, reproductive biology which includes gonad maturation stages, estimation of fecundity, size at sexual maturity and oocytes size frequency distribution of both species. The results were collected in compression to research already been done by researcher which includes size distribution, length weight relationship, linear regression analysis and growth determination by use of Von Bertalanffy Growth. Otolith based age calculation, relevant data on age and growth. Distribution of the Lutjanus lutjanus and Lutjanus johnii along Sindh coast (Pakistan) coast, the emphasis was placed on detailed study of histology of gonads for maturity stages and spawning season, population dynamics parameters. The main findings about both species of family Lutjanidae in Pakistani water are as follow: Both species Lutjanus lutjanus and L. johnii are spawning in November to February when temperature was 10 ºC to 21 ºC. In Lutjanus lutjanus size at 50% sexual maturity attained in smaller length male matured at 12.5 cm TL and female mature at 14.5 cm. The Lutjanus johnii male matures at 39 cm TL and female mature at 34 cm TL. Determinate the fecundity of both species, smallest specimen was observed in L. lutjanus 12 cm TL in length and 340 gm weight was calculated to have 143,264 eggs, and the largest fish of 27 cm in length has 1,768,468 eggs respectively. The mean fecundity of 45 specimens of L. lutjanus is calculated to be 938,888 ± 150,440. The Smallest L. johnii of 24.5 cm in length and 338 gm in weight was calculated to have 149,223 eggs, and the largest of 75 cm in length has 1,974,769 eggs respectively. In present study mature females of stage (V-VI) ovaries were selected during 2005-2007 and the relationship of fecundity and total length (cm) and weight (gm) were observed through log linear regression. The natural logarithm of fecundity, total length values were taken and relationship were described. The mean fecundity of 50 specimens of Lutjanus johnii is calculated to be 998,232 ± 180,490
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The delineation of opaque zone in the otolith is observed in winter during their spawning season, Both grow faster in smaller size but show slow growth in older age. Length frequency data of both shows more recruitment of small sizes. They are not being exploiting above the maximum sustainable yield in Pakistan. To increase the population of these species is necessary to adopt the modern technology of cage culture along the coastal belt of Pakistan and strictly implementation on fisheries rule regarding removal of ban nets (Tidal trap nets) from creek areas is most important to save the fisheries resources of Pakistan. The catch in smaller size of fish is very much disturbs the equilibrium of the habitat and the results of the present study shows there is a risk for the sustainability and directly effects the production. More management intervention is required to reduce the catch of small size fishes.
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