Indian Journal of Geo-Marine Sciences Vol. 42(6), October 2013, pp. 794-799

Allometric variations and condition factor in karachiensis (Winckworth, 1930) found at two adjacent rocky coasts of Karachi, Pakistan

Fatima Hayat Shaheen Zafar1* & Zarrien Ayub2 1Department of Zoology, University of Karachi, Karachi-75270, Pakistan 2Centre of Excellence in Marine Biology, University of Karachi, Karachi-75270, Pakistan *[E-mail address: [email protected]] Received 15 March 2012; revised 24 October 2012

Length-length and length-weight relationship and condition factor is described for Cellana karachiensis (Winckworth, 1930) collected between November 2007 and April 2009 from rocky shores of Buleji and Paradise Point. Maximum total length registered for this was 50 mm at Buleji and 40 mm at Paradise Point. Shell length-shell width, shell length- shell height and shell width-shell height showed strong relationship between the variables. Shell length-shell height relationships for C. karachiensis showed a positive allometry, which is common in high-shore in order to lower the rate of water loss in these . Value of b, the value of b > 3.0 for shell length and weight relationship indicated a positive allometric growth in C. karachiensis at both sites. Analysis of variance showed significant difference between the value of b during different seasons at Buleji and Paradise Point. Condition factor (CF) calculated for C. karachiensis ranged between 1.007 to 1.108 at Buleji and 1.008 to 1.064 at Paradise Point. Analysis of variance showed no significant difference between CF values in different seasons at two sites. A similar condition factor in different seasons showed that food availability remained constant throughout the year in coastal waters of Pakistan.

[Keywords: Length-weight, Condition factor, Cellana karachiensis, Karachi, Northern Arabian Sea]

Introduction Cellana karachiensis (Winckworth, 1930) Analyses of allometric relationships help to get is found on the rocky coasts of Karachi, Pakistan. No information about the basic ecophysiological published information of this species is available on characteristics of organisms, particularly vertebrates1. the geographical distribution, its growth and other However, there is a paucity of comparative studies on aspects of biology, with the exception of the the allometric relationships among aquatic morphometric studies from Gulf of Oman and 9 invertebrates including molluscs. The studies on Arabian Gulf . In the present study length-length and variations in shell shape of limpets have been length-weight relationships and the variation in attributed to exposure, desiccation stress, tidal height condition factor among seasons will be estimated for or a combination of these and other factors2-10. Cellana karachiensis on two rocky shores, Buleji and The knowledge on quantitative aspects such as Paradise Point, Karachi. length-weight relationship, length-length relationship, condition factor, growth and recruitment are Materials and Methods important tools for the adequate management of any 11 Cellana karachiensis species . Condition factor measures the affect of Samples of were collected various ecological and biological factors on the each month from rocky shores of Buleji and Paradise growth rate and reproduction of an individual. High Point, Karachi during November 2007 to April 2009. value of condition factor showed the degree of fitness The coast of Karachi (Fig. 1) located on the and suitability of the environment for the individual12. northeastern border of the Arabian Sea, is about Higher is the weight of limpet, the greater will be its 90 km long and its geographic coordinates are 24° condition factor11. King11 suggested that seasonal 48′ N latitude and 66° 59′ E longitude. Rocky ledge of variations in the condition of a limpet may be related Buleji is covered by boulders of varying sizes and to variations in food abundance and to different occupied by a diversified molluscan and crustacean reproductive stage. fauna, while the Paradise Point has hard platform and is comparatively much less populated than Buleji and ______*Corresponding author the abundant animals found here are limpets and 795 ZAFAR & AYUB: ALLOMETRIC VARIATIONS AND CONDITION FACTOR IN CELLANA KARACHIENSIS

data on condition factor (CF) of Cellana karachiensis was subjected to one way ANOVA to test for possible seasonal difference.

Results and Discussion

Length-length relationship A total of 722 specimens of Cellana karachiensis were examined from Buleji and 721 from Paradise point. Minimum total length of limpet recorded was 14 mm. In the present study the limpets smaller than

Fig. 1  A map showing the coastline of Pakistan 14 mm were not found at the sampling sites, which showed that juveniles limpets preferred a different barnacles. On each occasion, quadrats (50 cm × 50 cm) substratum than that preferred by their adults. were haphazardly place within the zone of occurrence Absence of small-sized limpets in the present study is of Cellana karachiensis and approximately 120 in agreement with the study of Thompson13 who individuals were removed with the help of spatula, reported that vulgata < 12 mm were either handpicked and were brought to the laboratory. A absent or few present in the area where adults were fixed numbers of individuals were used instead of a found. It has been reported that very young limpets fixed number of plots to make a comparison of size require a damp habitat and avoid dry rocks14-15. structure. Maximum total length of C. karachiensis recorded All shells were measured for total length, width and in this study was 40 mm from Paradise Point and

height to the nearest  0.1 mm with the help of vernier 50 mm from Buleji, which is substantially lower than 9 calipers. Weight ( 0.01 g) of each was taken those reported for the same species by Emam from on an electronic balance. Later the tissue was Gulf of Oman (Table 1). Maximum size of some removed from the shell and wet weight of tissue was species of Cellana and Patella reported from other taken. parts of the world are either smaller or similar in size Relationships between different lengths were to C. karachiensis with exception of C. testudinaria, examined by the linear regression equation P. flexuosa and P. ferruginea which are compara- Y = a + b*X. Values of a and b were estimated from tively much larger in size (Table 1). These length the log-transformed values of lengths in order to variations between sites may be correlated to the linearize the data. Student’s t-tests was used to ecological conditions of the habitats and/or with confirm whether b values obtained in the linear animal physiology16. regressions were significantly different from the Length-length relationships and the coefficient of isometric value (b= 1). 2 Relationship between shell length and total weight determination r are given in Table 2. In this study the and shell length and tissue wet weight of limpet was shell length-shell width relationships in C. karachiensis b showed a relatively strong relationship between the calculated by the allometric equation W = aL . Values variables (r² = 0.921 at Buleji; r² = 0.861 at Paradise of a and b were estimated from the log10 transformed Point). Value of b is significantly different from the values of length and weight, that is, log10 W = a + b theoretical slope of 1.0 at Buleji (P < 0.001, t-test log10 L. Student’s t-tests was used to confirm whether b values obtained for the length-weight relationship values given in Table 2) while at Paradise Point, the were significantly different from the isometric value shell length-shell width relationship is isometric (b= 3). Data on b value of length-weight relationship (Table 2). Shell length-shell height and shell width- was subjected to one way ANOVA to test for possible shell height relationships in this species were found to seasonal difference. be moderately correlated (in all cases: r² > 0.614) and the value of b is significantly different from the Condition factor (CF) was calculated as CF = theoretical slope of 1.0 (Table 2). Length-length Wcal./Wpred., where Wcal. is the weight of an relationships have been reported to be linear in individual and Wpred. is the weight of individual P. vulgata at three adjacent sites at Sandwick Bay, predicted from the length-weight relationship. The Orkney8. INDIAN J. MAR. SCI., VOL. 42, NO. 6, OCTOBER 2013 796

Table 1  Maximum shell lengths (mm) of Cellana and Patella spp. from various sources

and Zeal Pakistan Mediterranean

Khouw Indonesia (2007) Paracuellos et al.(2003) W. Emam(1994) Gulf ofEmam(1994) Oman Gulf Baxter (1983) Orkney Island Emam (1994) ofEmam Gulf Arabia Present Study. Paradise Point Present Study. Point Paradise Present study .Buleji Pakistan Present study .Buleji Dunmore and Schiel (2000) New Dunmore(2000) New Schiel and Ayas (2010)Mediterranean E. N. Bosch et al (1995) Gulf of Bosch Arabia et al (1995) Gulf Ismail and (1999) Red Ismail sea Elkrami Navarro et al (2005) Canary Navarro Islands et al (2005) Canary Species Species C. karachiensis - 49.2 55 ------40 50 C. radiata - - - - 38.5 ------C. rota - - - 45 50 ------C. testudinaria - - - - 90 - - - 31.5 - - - C. ornata - - - - - 49 ------P. flexuosa - - - 40 95 ------P. caerulea ------39 - - P. rustica ------48 - 42.5 - - P. ferruginea ------96 - - - - - P. vulgata 40 ------P. aspera ------51 - - - -

Table 2  Length-length relationships between shell length (SL), shell width (SW) and shell height (SH) in Cellana karachiensis. a, 2 intercept; b, slope; S.E., standard error; r , determination coefficient; *, P < 0.05; **, P < 0.001 Sites Equation Sample size a S. E. (a) b S. E. (b) r2 t-test Buleji SH=a+b*SL 722 0.123 0.036 1.205 0.026 0.740 7.72** SH=a+b*SW 0.205 0.028 1.121 0.022 0.776 5.37** SW=a+b*SL 0.066 0.235 0.854 0.009 0.921 -15.57** Paradise Point SH=a+b*SL 721 0.199 0.043 1.062 0.031 0.614 1.99* SH=a+b*SW 0.258 0.031 1.054 0.024 0.717 2.20* SW=a+b*SL 0.761 0.020 1.014 0.014 0.868 0.99 In the present study shell length-shell height showed a positive allometry in C. karachiensis. Analysis relationships for C. karachiensis showed a positive of variance showed significant difference between the allometry which is similar to the study on P. vulgata value of b (F = 4.31; df = 35; P < 0.05) during different at Sandwick Bay, Orkney in which the above- months at Buleji and Paradise Point. The b value in mentioned relationships also indicated a positive different seasons, NE monsoon (November-February), allometry8. While P. ferruginea from the Alboran spring inter-monsoon (March-April) SW monsoon Island, western Mediterranean has been reported to (May-September) and autumn inter-monsoon (October) show negative allometry between shell width-length is shown in Fig. 4. Statistically significant difference and shell height-length relationships10. Allometric was observed between the b values during different growth, where shell height increases more rapidly seasons at two sites (ANOVA, F = 5.29; df = 11; than shell length, is common in high-shore limpets P < 0.05). Higher value of b at Paradise Point showed and the rate of water loss in these animals is lower that the animal is gaining more weight than length, than in limpets which grow isometrically17. which could be related to the fact as there is less competition for food at Paradise Point where only Length-weight relationship limpets and barnacles are abundant. While at Buleji the Shell length-shell weight relationship corresponding fauna is highly diverse and thus there is competition for to the logarithmic form was W =  4.387 + 3.073 food as compared to Paradise Point. Such a conclusion 2 18 *TL (r = 0.949) at Buleji (Fig. 2) and W= 4.679 + has also been reached by Bosman and Hockey who 3.272*TL (r2= 0.940) at Paradise Point (Fig. 3). Value of correlated the limpet growth to rate of algal production. b equal to 3.073 at Buleji and 3.272 at Paradise Point Lewis and Bowman7 have reported that the population 797 ZAFAR & AYUB: ALLOMETRIC VARIATIONS AND CONDITION FACTOR IN CELLANA KARACHIENSIS

Fig. 3  Shell length-shell weight and shell length-tissue wet Fig. 2  Shell length-shell weight and shell length-tissue wet weight relationships of Cellana karachiensis at Buleji weight relationships of Cellana karachiensis at Paradise Point

Fig. 4  Seasonal variation in the b value for length-weight relationships of Cellana karachiensis of Patella vulgata showed different length-weight relationships in different habitats, which is similar to our study in which C. karachiensis showed different length weight relationships at two different sites, Buleji and Paradise Point. The value of b reported in this study is 3.07 at Buleji and greater than 3.27 at Paradise Point for C. karachiensis, which is similar to value of b reported for C. karachiensis from Gulf of Arabia9, for C. radiata from India5 and for P. vulgata from Fig. 5  Seasonal variation in the mean condition factor of Cellana karachiensis. The vertical lines show standard deviations Scotland8 (Table 3) but is higher than reported for C. karachiensis from Gulf of Oman9, and for C. radiata In the present study the shell length and wet tissue from exposed coast of Waltair, India5 (Table 3). weight relationship (Figs 2 & 3) was estimated as INDIAN J. MAR. SCI., VOL. 42, NO. 6, OCTOBER 2013 798

Table 3  Parameter ‘b’ of length-weight relationships in some patellid limpets Species Area Shell length- Shell length Sources shell weight ‘b’ wet tissue weight ‘b’

C. karachiensis Buleji, Karachi 3.07 2.73 Present study C. karachiensis Paradise Point, Karachi 3.27 2.97 Present study C. karachiensis Gulf of Arabia 3.11 2.79 Emam (1994) C. karachiensis Gulf of Oman 2.74 2.78 Emam (1994) C. radiata India (high-exposed) 2.67 - Rao and Ganapati (1971) C. radiata India (high-protected) 3.19 - Rao and Ganapati (1971) C. radiata India (low-exposed) 3.08 - Rao and Ganapati (1971) C. radiata India (low- protected) 3.30 - Rao and Ganapati (1971) P. vulgata Scotland 3.34-3.61 - Baxter (1983)

3 Moore H B, The relation of shell growth to environment in W= 4.013 + 2.733*TL (r = 0.921) at Buleji and  9 Patella vulgata, Proc. Malacol. Soc. London., 21 (1934) 217- W= 4.437 + 2.975*TL (r= 0.862). Emam has reported 222. almost similar values of b, 2.79 and 2.78 in shell 4 Davies P S, Effect of environment on metabolic activity and length-wet tissue weight relationship of C. karachiensis morphology of Mediterranean and British species of Patella, from Gulf of Arabia and Gulf of Oman, respectively Pubblicazioni Della Stazione Zoologica di Napoli., 37 (1969) (Table 3). 641-656. 5 Rao B M. & Ganapati P N, Ecological studies on a tropical Condition Factor limpet, Cellana radiata. Structural variations in the shell in relation to distribution, Mar. Biol., 10 (1971) 236-243. The condition factor (CF) calculated for 6 Bannister J V, Shell parameters in relation to zonation in C. karachiensis ranged between 1.007 to 1.108 with Mediterranean limpets, Mar. Biol. 31 (1975) 63-67. an average of 1.009  0.13 at Buleji and 1.008 to 7 Lewis J R & Bowman R S, Local habitat-induced variations Patella vulgata J. Exp. Mar. 1.064 with an average of 1.024  0.15 at Paradise in the population dynamics of , Biol. Ecol., 17 (1975) 165-203. Point (Fig. 5). CF value of 1.02 obtained in this study 8 Baxter J M, Allometric relationships of Patella vulgata L. is slightly lower than the CF value of 1.23 for Cellana Shell characters at three adjacent sites at Sandwick Bay in karachiensis from the Gulf of Oman and the Arabian Orkney, J. Nat. Hist., 17 (1983) 743-755. Gulf9 and 1.25 for C. testudinaria from Indonesia19. 9 Emam W M, Morphometric studies on the limpet Cellana karachiensis (: ) from the Gulf of Oman Analysis of variance showed that there is statistically and Arabian Gulf, Indian J. Mar. Sci., 23 (1994) 82-85. no significant difference between the CF values 10 Paracuellos M, Nevado J C, Moreno D & Giménez A, during different months at two sites (ANOVA, Conservational status and demographic characteristics of (Gmelin, 1791) (Mollusca, Gastropoda) F = 0.282; df = 35; P > 0.05). Statistically no significant difference was observed between the CF on the Alboran Island (Western Mediterranean), Anim. Biodiv. Conser., 26 (2003) 29-37. values during different seasons at two sites (ANOVA, Fisheries Biology, Assessment and Management 11 11 King M, . F = 0.51; df = 11; P > 0.05). King has proposed that Wiley-Blackwell. (2007) the greater is the weight of limpet, the greater will be 12 Saad A E A, Age, growth and morphometry of the limpet its condition. According to him11 seasonal variations Cellana eucosmia (Mollusca: Gastropoda) from the Gulf of Indian J. Mar. Sci in the condition of a limpet may reflect variations in Suez. ., 26 (1997) 169-172. 13 Branch G M, Limpets: their role in littoral and sublittoral food abundance and the reproductive stage. In our community dynamics, in: The Ecology of Rocky Coasts, study the condition factor was almost similar in edited by P.G. Moore & R. Seed, (London: Hodder & different seasons which showed that food availability Stoughton) 1985, pp. 97-116. remained constant throughout the year in coastal 14 Thompson G B, Population dynamics of the limpet Patella vulgata (L) in Bantry Bay, J. Exp. Mar. Biol. Ecol., 45 waters of Pakistan. (1980) 173-217. 15 Jones N S, 1948, Observations and experiments on the References biology of Patella vulgata at Port St. Mary, Isle of Man, 1 Schmidt-Nielsen K, Scaling in biology: the consequences of Proc. Trans. Liverpool Biol. Soc., 56 (1948) 60-77. size, J. Exp. Zool., 194 (1975) 287-308. 16 Ballantine W J, The population dynamics of Patella vulgata and 2 Russell E S, Environmental studies on the limpets, Proc. other limpets. Ph. D. Thesis, University of London, UK, 1961. Zool. Soc. London, 58 (1907) 856-870. 17 Le Cren E D, The length-weight relationship and seasonal 799 ZAFAR & AYUB: ALLOMETRIC VARIATIONS AND CONDITION FACTOR IN CELLANA KARACHIENSIS

cycle in gonad weight and condition in the perch (Perca 19 Khouw A S, Ecological studies on the tropical limpet fiuviatilis), J. Anim. Ecol., 20 (1951) 201-219. Cellana testudinaria (Linnaeus, 1758) influence of 18 Bosman A L & Hockey P A R, The influence of primary environmental factors on the rocky shore benthos of the Big production rate on the population dynamics of Patella Kai Island, Southeast Molluccas, Indonesia. Ph. D. thesis, granularis, an intertidal limpet, Mar. Ecol., 9 (1988) 181-198. University of Kiel, Germany, 2003.