Journal of Sci. Res. Dev. 2013, Vol. 14, 47 - 54

Aspects Of The Biology And Culture Trials Of From Lagos Lagoon

1*Soyinka, O. O., 1Ayoola, S. O., 1Onyema, I. C. and 1Ayeni, M. O. 1 Department of Marine Sciences, University of Lagos, Nigeria.

ABSTRACT The occurrence, length-frequency distribution, length-weight relationship and condition factors of 449 specimens of cichlids, Sarotherodon melanotheron, Tilapia zilli, Tilapia guineensis and Hemichromis fasciatus from Lagos Lagoon were investigated from September 2009 - February 2010. The relative abundance of the species collected from the lagoon was: S. melanotheron (45.43%), T. zilli (26.73%), T. guineensis (26.06%) and H. fasciatus (1.78%). All the cichlids were found throughout the sampling period except H. fasciatus which was collected only in February. The standard length of S. melanotheron ranged from 8.0 – 14.5cm (weight: 22.00 – 90.00g), T. zilli (SL: 8.0 – 14.5cm; weight: 32.80 – 108.00g), T. guineensis (SL: 9.0 – 17.0cm; weight: 42.00 – 85.00g) and H. fasciatus (SL: 11.0 – 14.0cm; weight: 65.00 – 84.00g). The frequency polygon reflected one age group in S. melanotheron, one age group in T. zilli, three age groups in T. guineensis and two age groups in H. fasciatus. The species exhibited negative allometric growth with regression coefficient (b) values between 0.729 – 2.0918. The K-value for S. melanotheron was 4.65 (mean, 2.07 ± 0.33); T. zilli, 3.93 (mean, 1.77 ± 0.54; T. guineensis, 3.64 (mean, 1.74 ± 0.66, and H. fasciatus, 3.63 (mean, 1.94 ± 0.28). Culture potential of S. melanotheron (53 males and 47 females) in freshwater concrete pond was also examined from August 2010 – February 2011. Average fecundity per adult female ranged between 21 and 128eggs for fish with weight ranging from 30.00g to 78.00g. The culture trial of S. melanotheron revealed its ability to tolerate and thrive in both brackish and freshwater conditions and this makes it an excellent candidate for aquaculture purposes. Proper management strategies needed to be employed in commercial production and the conservation of this rich resource in the wild.

Keywords: Cichlid species, concrete pond, length, weight, growth, culture

INTRODUCTION estuaries, creek and lagoon systems. Tilapias are popular cultured species because of their high salinity Tilapia is a spiny-finned freshwater fish of the tolerant characteristics higher than 30‰. Some Family Cichlidae, native chiefly to Africa and the species like Tilapia guineensis, Sarotherodon Middle East (Pullin and McConnell, 1982). They are melanotheron, T. zillii and O. mossambicus can economically important as food fishes both in their tolerate salinities from 0 to 120‰ (Trewavas, 1982). native regions and elsewhere, where they have been Cichlid species are intensely utilised in the coastal introduced or are grown in fish farms. Tilapias have a communities and there are reports of overfishing in mild tasty flesh, but the skin has a bitter flavor the lagoons (Solarin, 1998; Emmanuel, 2009). (Trewavas, 1983; FAO, 1993). They have adapted to Overfishing of these species without means of diverse habitats, permanent and temporary rivers, replenishing the stock would lead to their extinction lakes, tropical and subtropical rivers open and closed eventually. Thus there is the utmost need to seek estuaries, lagoons, swamps and brackish water areas means of conserving or rationally managing the stock (Trewavas, 1983). Kuton and Kusemiju (2010) especially through aquaculture of the local species. highlighted that the best known genera of cichlid in Nigeria are Tilapia (Fagade, 1971), Hemichromis The objectives of this study were to examine some (Fagade and Olaniyan, 1973) and Chromidotilapia aspects of the biology of cichlids occurring in the (Fagade, 1983) each representing a distinct ecological Lagos Lagoon and provide information on the culture type. Another is Sarotherodon which was potentials of the black jaw Tilapia, S. melanotheron reported by Trewavas (1983). There is an increasing reared in freshwater pond, for the rational interest in cichlids for aquaculture purposes, most management of cichlid species in the lagoon. especially in areas of fluctuating salinities typical of

*Correspondence author- [email protected]

48 Soyinka, O. O., Ayoola, S. O., Onyema, I. C. and Ayeni, M. O.

MATERIALS AND METHOD tends to have the same distribution (Bagenal and Tesch, 1978). The number of each fish specimen was Description of Study Area: The Lagos Lagoon (Fig. plotted against their length frequency percentage. 1) is the largest of the lagoon system of the West o / African sub-region. It lies between longitude 3 20 Length–Weight Relationship: Length – weight and 3o40/E and latitudes 6o15/ and 6o40/ N. It has an 2 relationship was used to determine the growth pattern area of 208km . It supports small scale fisheries over and was represented by the equation: the years. It empties into the Gulf of Guinea located along the south-western coastal region of Nigeria Log W = Log a + b Log L, (Fagade, 1969). It is characterized by seasonal fluctuations in salinity (Hill and Webb, 1958). It Where W = whole body weight in grams; a = borders the forest belt and receives a large number of regression constant; b = regression coefficient and L important rivers like the Yewa, Ogun, Osun and Ona = standard length in centimetres Rivers. Lagos Lagoon opens into the Atlantic Ocean from an extensive harbor which serves as a major Condition Factor: The condition factor is the state outlet of fresh water from the lagoon system during of the general well-being or how fat or lean a fish is. the rainy season. It is opened throughout the year and It was calculated using the formula: exposed to semi–diurnal tides (Fagade, 1969). K = 100W/L3 Specimen Collection: The samples (449) of cichlid species for the study of the biology were collected in Where K = condition factor Lagos Lagoon at the local fish landing jetty, Makoko between September 2009 and February, 2010. The L = standard length in centimetres (cm), samples collected were identified using appropriate W = weight of fish in grams (g) texts (Olaosebikan and Raji, 1991) and personal Culture Experiment: After acclimatization, a total communication with fish experts. They were sorted into the different cichlid species and were of 53 matured males and 47 matured females were immediately kept in a deep freezer at a temperature used for the culture experiment. Records of the 0 mortality in adults and offspring produced monthly of -20 C in the Marine Research Laboratory, were taken. The offspring were normally removed University of Lagos, Nigeria. For the culture from the culture tank into nursery tanks monthly. experiment, 151 live specimens of S. melanotheron Water quality parameter in the pond such as were collected in August 2010 from the mariculture cages of Marine Sciences Department and Lagos temperature was measured using mercury State Ministry of Agriculture, and transported to the thermometre; dissolved oxygen (DO) with DO-metre and pH using pH-metre, daily for two weeks. The concrete pond of the department for acclimatisation culture trial spanned from August 2010 to February and investigation of its culture potentials. This study 2011. The fish were fed coppens feed in powdery was done in a pond independent of the samples for the fish biology study. form.

Laboratory Procedures: The fish samples for the RESULTS study of the biology were removed from the freezer Occurrence: Four species of cichlids (S. and thawed. After thawing, the length was measured melanotheron, T. zilli, T. guineensis and H. fasciatus) to the nearest 0.1cm using a measuring board. The were caught in the Lagos Lagoon from September total length was taken as the distance from the tip of 2009 to February 2010. The relative abundance of the snout to the tip of the caudal ray while the the species collected was as follows: S. melanotheron standard length was taken as the distance from the tip (45.43%), T. zilli (26.73%), T. guineensis (26.06%) of the snout to the hidden base of the caudal ray. and H. fasciatus (1.78%). All the species were Weight of each sample was carefully taken using the present throughout the sampling period in the lagoon electric weighing scale (Camry EK 5055) calibrated except H. fasciatus which occurred only in February in gram to the nearest 0.01g. 2010.

Length–Frequency Distribution: The length Length-frequency distribution: The standard length frequency distribution was used to estimate the age of S. melanotheron ranged from 8.0 – 14.5cm group of the cichlid species from the lagoon. It is (weight: 22.00 – 90.00g), T. zilli (SL: 8.0 – 14.5cm; based on the fact that the length of a particular size weight: 32.80 – 108.00g), T. guineensis (SL: 9.0 –

Aspects Of The Biology And Culture Trials Of Cichlids From Lagos Lagoon 49

17.0cm; weight: 42.00 – 85.00g) and H. fasciatus T. guineensis: Log W = 1.018 + 0.7290 Log L (SL: 11.0 – 14.0cm; weight: 65.00 – 84.00g). (n = 117, r = 0.5456) The standard length-frequency distribution is shown in Fig. 2. The frequency polygon reflected one age H. fasciatus: Log W = 0.9137 + 0.8603Log L group in S. melanotheron, one age group in T. zilli, three age groups in T. guineensis and two age groups (n = 8, r = 0.8285) in H. fasciatus. The size group 8.5 – 9.4cm formed the most abundant group in S. melanotheron, 10.5 – The cichlid species exhibited negative allometric 11.4cm in T. zilli, 9.5 – 10.4cm in T. guineensis and growth. High correlation (r) values between the 11.5 – 12.4cm in H. fasciatus. weight and standard length, 0.5736 and 0.8285 respectively, of the cichlids in the lagoon are a strong Length-weight relationship: Fig 3 illustrated the indication that an increase in standard length of the length-weight relationship of the species, while the species gave an increase in the weight. summary is presented below: Condition factor: The summary of the variations in S. melanotheron: Log W = -0.4626 + 2.0918 Log L condition factor by species of cichlids from the lagoon are presented in Table 1. The K-value for S. (n = 204, r = 0.7076) melanotheron was 4.65; T. zilli, 3.93; T. guineensis, 3.64, and H. fasciatus, 3.63. The highest K-value was T. zilli: Log W = 0.5736 + 1.1580 Log L recorded for S. melanotheron, while the lowest K- value was recorded for H. fasciatus. (n = 120, r = 0.5736)

Table 1: Condition factor (K) of cichlid species from the Lagos Lagoon (September 2009 – February 2010).

Species Standard length (cm) Weight (g) K = 100W/L3

S. melanotheron 9.6 41.17 4.65

T. zilli 11.4 58.23 3.93

T. guineensis 12.1 64.49 3.64

H. fasciatus 12.6 72.63 3.63

Culture Trial of S. melanotheron within the first 2 days of acclimatisation in the tank, while there were no further mortalities from the 3rd (i) Water quality parameters in culture: The day of acclimatization and throughout the culture weekly pond water physico-chemical parameters are trial. The percentage mortality was 0%, while illustrated in Fig. 4. There were no remarkable percentage survival was 100% during culture trial. variations in the temperature, dissolved oxygen and pH of the culture medium. (iii) Reproduction in pond: Table 2 showed the monthly collection of offspring produced in the (ii) Mortality / Survival of S. melanotheron culture tank. The pond was sampled independent of during the trial. A total of 51 mortalities occurred the fish biology study.

50 Soyinka, O. O., Ayoola, S. O., Onyema, I. C. and Ayeni, M. O.

Table 2: Random monthly collection of offspring of S. melanotheron in culture pond

Month No. of offspring Average fecundity per female

August, 2010 985 21 (20.96)

September, 2010 1300 28 (27.66)

February, 2011 3735 80 (79.47)

Total 6020 128 (128.09)

DISCUSSION further explain their level of success in the Lagos Lagoon. The variations of K in fish according to In the present study, four cichlid species were King (1995) may be indicative of food abundance, collected in the lagoon throughout the sampling adaptation to the environment and gonadal period. Kuton (2006) however reported three species, development. Anene (2005) reported a mean K-value which excluded T. zilli in the Lagos Lagoon. Fagade of 4.3±0.19 for T. zilli in Umuoseriche Lake. The and Olaniyan (1974) also did not report T. zilli in condition factors of cichlid species in the present Lagos Lagoon, but recorded T. mariae which Kuton study were generally higher than those reported by (2006) did not encounter in his investigation. Kuton (2006) in the same lagoon. Condition factor However, Soyinka and Kassem (2008), and Soyinka decreases with increase in length (Bakare, 1970; et al, (2010) reported the occurrence of the four Fagade, 1979); and also influences the reproductive species in this present study in addition to T. mariae cycle in fish (Welcomme, 1979). Lagler (1956) in Ologe and Badagry Lagoons, which are part of the summarized the importance of determining the lagoons in the Lagos area. relationship between the body weight and the body length of fishes and considered the condition factor In the tropical region, the determination of age is as a useful tool in expressing the relative robustness often particularly difficult (Fagade, 1974), since the of fishes. fish experience little seasonal environmental changes and therefore lay down no definite annual rings The physico-chemical parameters measured in the (Ezenwa and Kusemiju, 1981).Thus, length- pond indicated a favourable culture condition for the frequency distribution polygon in the present study cichlid, and this could be adopted in large scale revealed one to three age groups of cichlid species in cichlid production. The parameters were within the lagoon. Kuton (2006) reported three age groups recommended range for cichlids. of cichlids in the lagoon. Fagade (1974, 1983)) observed ages one to five years in T. melanotheron The mass mortality recorded within the 1st and 2nd and Chromidotilapia guentheri Length and weight days in the freshwater acclimatisation pond could be measurements in conjunction with age data can give as a result of the stress from handling from the point information on the stock composition, age at of cropping to the concrete tank for rearing. The maturity, life span, mortality, growth and production change from saline environment to a freshwater (Beyer, 1987; King, 1996a and b). Length-weight condition may not have contributed much to the mass data are often used as an indication of fatness or mortality because very low salinity is usually general well being (Le Cren 1951). Several authors recorded in August in the Lagos Lagoon. Kuton have reported both isometric and allometric growth (2006) and Soyinka (2010) recorded a salinity of 1.0 for different fish species from various water bodies. – 3.0‰ in August. There were no mortalities King (1991) reported allometric growth patterns for recorded in the pond from the 3rd day of the Tilapia species from Umuoseriche Lake, while observation. negative allometric growth pattern was recorded for the cichlids in the present study. Hickling (1961) remarked that Tilapia species exhibit stunted growth due to rapid reproductive rate. Fryer The cichlid species in the present study had a and lles (1972) also reported that stunted growth did considerable high condition factor and this could not necessarily depend on scarcity of food. In the

Aspects Of The Biology And Culture Trials Of Cichlids From Lagos Lagoon 51 present study, there was remarkable growth in length CONCLUSIONS and weight of S, melanotheron in the concrete pond With increasing scarcity of brackish water fish and this could be due to the removal of the offspring available for aquaculture especially in the Lagos produced, to nursery tanks, so as to avoid Lagoon due to overfishing, development of tilapias overcrowding which leads to stunted growth. that tolerate low salinity would increase fish (and Hickling (1961) however noted that cichlid fish are hence protein) production. Inter-specific capable of growth throughout life and that each variation in salinity tolerance may be used to select species has average limiting size. The spawning salt-tolerant species and develop salt tolerant hybrids. frequency noticed in the pond was on an interval of 2 The culture trial of S. melanotheron revealed its weeks, and this agreed with the report of Legendre ability to tolerate and thrive in both brackish and and Ecoutin (1989) for S. melanotheron. The average freshwater conditions and this makes it an excellent offspring produced per female was approximately candidate for aquaculture purposes. Proper 128 offspring. In the wild, Kuton (2006) recorded an management strategies needed to be employed in average fecundity of 242 eggs for S. melanotheron in commercial production and the conservation of this Lagos Lagoon. Variations in fecundity in this species rich resource in the wild. could be as a result of size variations of the matured female and there was a noticeable increase in number ACKNOWLEDGEMENT of offspring produced as the months progressed. Anene and Okorie (2008) reported that fecundity was The assistance of Dr. Emmanuel of the Department positively correlated with total length, standard of Marine Sciences, in the identification of the cichlid length, body weight and ovarian weight. It is species is greatly appreciated. The unrelenting efforts therefore expected that an increase in the number of of Mr. Akapo and the following staff of the fry produced would occur as increase in weight and department: Mrs Babalola and Miss Suberu, during length occurred. the culture trial experiment are highly commendable.

REFERENCES Ezenwa, B.I. and Kusemiju, K. (1981). Age and growth determination of the catfish, Anene, A. (2005). Condition factor of four cichlid Chrysichthys nigrodigitatus (Lacepede). species of a man-made lake in Imo state, south- Journal of Fish Biology, 19 (3): 345 – 351. eastern Nigeria. Turkish Journal of Fisheries Fagade, S.O, (1969). Studies on the biology of some and Aquatic Sciences 5: 43-47. fishes and the fisheries of the Lagos Lagoon, Anene, A. and Okorie, P.U. (2008). Some aspects of Ph.D. Thesis, University of Lagos. the reproductive biology of Tilapia mariae Fagade, S. O. (1971). The food and feeding habits of (Boulenger 1901) in a small lake in Tilapia species from the Lagos Lagoon. Journal southeastern, Nigeria. African Journal of of Fish Biology, 3: 151 - 156. Biotechnology, 7 (14): 2478-2482. Fagade S.O, (1974). Age determination in Tilapia Bagenal, T.E. and Tesch, F.W. (1978). Age and melanotheron (Ruppell) in the Lagos Lagoon, growth. In: Methods for Assessment of Fish Nigeria with a discussion of the environmental Production in Fresh waters, (Bagenal, T., ed.), and physiological basis of growth marking in pp 101- 136, Oxford, Blackwell. the tropics in ageing of fish, pp 71-77. Bakare, O. (1970). Bottom deposits as food of Inland Fagade, S.O. (1979). Observation of the biology of fresh water fish. In: Kainji, A Nigerian Man- two species of Tilapia from the Lagos Lagoon Made Lake. S.A. Visser, (Ed.), Kanyi Lake Nigeria. Bull. Inst. Fond Afr. Nore (Ser. A) 41: Studies Vol. 1. Ecology Published for the 627-658 Nigerian Institute. Fagade, S.O. (1983). The biology of Chromidotilapia Beyer, J.E. (1987). On length weight relationship. guentheri from a small lake. Arch. Hydrobiol. Part 1: computing the mean weight of the fish 97: 60-72. of a given class. Fish byte 5: 11-13. Fagade, S. O. and Olaniyan, C. I. O. (1973). The food Emmanuel, B.E. (2009). The artisanal fishing gears, and feeding interrelationship of fishes of the crafts technology and their efficiency in the Lagos Lagoon. Journal of Fish Biology, 5: 205 Lekki lagoon, Nigeria. Ph.D Thesis, University - 225. of Lagos, 268pp.

52 Soyinka, O. O., Ayoola, S. O., Onyema, I. C. and Ayeni, M. O.

Fagade, S. O. and Olaniyan, C. I. O. (1974). Seasonal condition in the perch Perca fluviatilis. Journal distribution of the fish fauna of the Lagos of Animal Ecology, 20(2): 201-219. Lagoon. Bull. De I..I. F. A. N. T. (Ser. A), Legendre, M. and Ecoutin, J.M. (1989). Suitability of 36(1), 244.252. brackish water tilapia species from the Ivory FAO, Fishery Information, Data & Statistics Service Coast for lagoon aquaculture. Aquatic Living (1993). Aquaculture Production, FAO 815: 20 Resources, 2, 71-79 – 21. Olaosebikan, B. D. and Raji, A. (1991). Field guide Fryer, G. and Illes, T.D. (1972). The Cichlid fishes of to Nigerian freshwater fishes. Federal College the great lakes of Africa: their biology and of Freshwater Fisheries Technology, New evolution. Oliver and Boyd, Edinburgh, Bussa, Nigeria, 106pp. Scotland, 641pp. Pullin, R.S.V. and Lowe-McConnell, R.H. (1982). Hickling, C.F. (1961). Tropical inland fisheries. The biology and culture of tilapias. ICLARM Longmans green and co Ltd, London and Conference Proceedings 7, International Center Southampton, 287 pp. for Living Aquatic Resources Management, Hill, M.B. and Webb, J.E. (1958). "The ecology of Manila, Philippines. 432 pp. Lagos lagoon II. The topography and physical Solarin, B.B. (1998). The hydrobiology, fishes and features of the Lagos harbour and Lagos fisheries of the Lagos Lagoon, Nigeria. Ph.D lagoon". Philosophical Transaction of Royal Thesis. University of Lagos, 235pp. Society, London. 241:307‐417. Soyinka, O.O. (2010). The bio-ecology and culture King, R.P. (1991). The biology of Tilapia mariae potentials of the grey mullet, Mugil cephalus (Boulenger 1899) in a Nigeria rainforest stream. (Linnaeus) from Lagos Lagoon, Nigeria. Ph.D Ph.D.Thesis, Department of Zoology, Thesis, University of Lagos, 223pp. University of Port Harcourt, Nigeria. Soyinka, O.O. and Kassem, A.O. (2008). Seasonal King, M. (1995). Fisheries biology, assessment and variation in the distribution and fish species management. Fishing News Books, Oxford, diversity of a tropical lagoon in south-west England. 341pp. Nigeria, Journal of Fisheries and Aquatic King, R.P. (1996a). Length-weight relationship of Sciences, 3 (6): 375 - 383 Nigerian freshwater fishes. Naga, ICLARM Q. Soyinka, O.O., Kuton, M.P. and Ayo-Olalusi, C.I. 19:49-52. (2010). Seasonal distribution and fish species King, R.P. (1996b). Length-weight relationship of richness in Badagry Lagoon, south-west Nigerian coastal water fishes. Naga, ICLARM Nigeria. Estonian Journal of Ecology, 59 (2): 1 Q. 19(4):53-58. – 10. Kuton, M.P. (2006). The biology of cichlid fishes Trewavas, E. (1982). Tilapia and from Badagry, Lagos, and Lekki Lagoon South- speciation, In: Pullin, R.S.V. and Lowe- west, Nigeria. Ph.D Thesis University of Lagos, McConnell, R.H. (eds.), The Biology and Lagos, 280pp. Culture of Tilapias. ICLARM Conference Kuton, M. P. and Kusemiju, K. (2010). Species Proceedings 7, International Center for Living Diversity and Richness of Cichlids in Three Aquatic Resources Management, Manila, Southwestern Lagoons in Nigeria. Journal of Philippines, pp 3-13. Sci. Res. Dev. 12, 22 – 33. Trewavas, E. (1983): Tilapine fishes of the Genera Lagler, K.F. (1956). Freshwater fishery biology. Sarotherodon, Oreochromis and Danakilia. Second edition. Won. C. Brown Company British Museum (Natural History), London, Limited Lowa. 120-166. 340pp. LeCren, E.D. (1951). The length-weight relationship Welcomme, R.L. (1979): Fisheries ecology of flood and seasonal cycle in gonad weight and plain rivers. Longman Press, London. 317pp.

Aspects Of The Biology And Culture Trials Of Cichlids From Lagos Lagoon 53

Figure 1: Map of Lagos Lagoon, Nigeria

S. melanotheron 30 25 20 15 10

% frequency % 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Standard length (cm)

T. zilli 30 25 20 15 10

% frequency % 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Standard length (cm)

T. guineensis 25 20 15 10

% frequency % 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Standard length (cm)

H. fasciatus 40 30 20

10 % frequency % 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Standard length (cm)

Figure 2: Standard length-frequency distribution of cichlid species from the Lagos Lagoon (September 2009 – February 2010).

54 Soyinka, O. O., Ayoola, S. O., Onyema, I. C. and Ayeni, M. O.

S. melanotheron 2.00 1.80 1.60

Log weight Log 1.40 1.20 0.85 0.95 1.05 1.15 1.25 Log standard length

T. zilli 2.20 2.00 1.80

Log weight Log 1.60 1.40 0.90 1.00 1.10 1.20 1.30 Log standard length

T. guineensis 2.00 1.90 1.80 1.70

Log weight Log 1.60 1.50 0.90 1.00 1.10 1.20 1.30 Log standard length

H. fasciatus 1.95

1.90

1.85 Log weight Log

1.80 1.02 1.04 1.06 1.08 1.10 1.12 1.14 1.16 Log standard length Figure 3: Log standard length / Log weight relationship of cichlid species from Lagos Lagoon (September 2009 – February 2010).

Fig. 4: Weekly pond water physico-chemical parameters during the culture trial of S. melanotheron