Elops Lacerta Research Articles

Human health risk assessment of heavy metals detected in dried fish species consumed in Benin City, Edo State, Southern Nigeria

Heavy metal content and its associated hazard risk to human health were assessed in dried fish species commonly consumed in Benin city metropolis. In this study, three commercially available dried fish species Elops lacerta (ten pounder), Clarias gariepinus (catfish) and Cynoglossus senegalensis (sole fish) were purchased from selected markets in Edo State, Southern Nigeria. Result indicates that the heavy metal content was higher in Elops lacerta fish than the other fish species. On average, levels of Cd (0.23±0.03 mg/kg), Cu (10.50±2.87 mg/kg), Pb (0.14±0.03 mg/kg) and Zn (24.97±2.41 mg/kg) in all three fish species were below the maximum acceptable limits except for Fe (44.44 ±3.18 mg/kg). The metal pollution index (MPI) in fish species was below 100. Estimated daily intake (EDI) for the metals was lower than the tolerable daily intake (TDI). Target hazard quotient (THQ) of all metals was below 1, but the total THQ values for associated metals were above 1 for children, suggesting a non-carcinogenic health risk to children. Target carcinogenic risk (TR) was within the acceptable limits of 10 –4 to 10 –6 indicating low carcinogenic risk to the consumer. We recommend that the dried fish species in the studied areas should be closely monitored to protect consumer health, especially in children.

Fishing methods, catches composition and exploited biomass in the Aby lagoon (Adiaké, Côte d’Ivoire)

Ivorian lagoon water bodies contribute to the fight against food insecurity through fisheries. They provide fresh and competitive products to the local population. Thereby, strategies for their rational and sustainable exploitation must be put in place. This study aimed at contributing to the improvement of fishing activities in the Aby lagoon. It is the result of three months of surveys (from January to March 2020) with the fishermen and the fisheries administration. It appears that fishing is practiced by indigenous peoples. The most represented were aged over 45 years old (71.30%). Gillnets (65.59%) and nailed plank canoes (67%) were the most used. However, Aly nets (5.63% of fishing gears types) remain the most productive providing 80% of catches. The main fish species recorded were Ethmalosa fimbriata (Clupeidae), Elops lacerta (Elopidae) and Sarotherodon melanotheron (Cichlidae). However, the effective management of the water body still remains a major concern. Indeed, constraints were mainly: the non-submission of individual fishermen to the fisheries administration, the struggle for space reserved for fishing between individual and collective fishermen, the use of non-selective gears such as the Aly net. Thus, it seems necessary to train and sensitize the actors on the concept of sustainable development and to apply the management rules for a rational exploitation of this fishery.

Report on the incidences of skeletal anomalies in three fish species from Bonny tributary (Niger delta), Nigeria

Three cases of skeletal anomalies in fishes Elops lacerta Valenciennes, 1847 (family Elopidae), Oreochromis niloticus (Linnaeus, 1758) (Cichlidae) and Arius latiscutatus Günther, 1864 (Ariidae) collected in the Elechi Creek, a tributary of the Bonny River (Niger delta) were reported for the first time in the present study. The anomalies are pugheadness, complete absence of pelvic fins and deformed dorsal, pectoral and pelvic fins. Three specimens of E. lacerta have shown the case of pugheadness but at different levels of severity. The specimen of O. niloticus showed a complete absence of the pelvic fins. Externally, the area where the bases of the pelvic fins should be found (underneath the pectoral fins) showed a normal scale covering (in scale form and size). Internally and by using radiography, no trace of the pelvic fins and the basipterygia were observed. The specimen of A. latiscutatus showed severe deformation of the finrays of the dorsal, pectoral and ventral fins. The spines of the pectoral and dorsal fins were also deformed. Pollution from Port Harcourt appears to be causing the skeletal deformities described.

Tidal influence on fish faunal occurrence and distribution in an estuarine mangrove system in Ghana

This study assessed the effects of tidal stages and habitat conditions on nekton assemblage and distribution in the Kakum River estuarine mangrove system in the Central Region of Ghana. Teleosts and crustaceans were sampled using pole seine and cast net from a tidal mangrove pond and a channel, and characterised using morphometry and ecological guilds concept. In total, 1 146 specimens were collected, with 35 species from 19 families represented. The most abundant species encountered were Liza spp. (Mugilidae; 36%), Sarotherodon melanotheron (Cichlidae; 16%), Elops lacerta (Elopidae; 6%) and Sardinella aurita (Clupeidae; 5%), which exhibited pronounced spatial distribution. Sarotherodon melanotheron showed preference for ponds with minimal water flow and depth, Sardinella aurita occurred only in deeper sections of the mangrove channel with significant flow velocity, and Elops lacerta in the pond and all channel stations. Mugilids were found exclusively in the channel, whereas Palaemonidae (Macrobrachium macrobrachion and M. vollenhoveni) occurred in specific locations in the channel, with species- specific preferences for tidal stages. Most species encountered were identified to be predominantly marine migrants with bentophagous feeding habit. Site selection and tidal stages were found to affect the occurrence and distribution of fishes over a tidal cycle and interactively influence species diversity.

Catalogue of Some Saltwater and Freshwater Fish Species of the Niger Delta Region of Nigeria

The study was done to review some saltwater and freshwater fish species in the Niger Delta region of Nigeria. The Niger Delta is one of the most prominent regions in Nigeria, endowed with several water bodies that are distributed as freshwater like rivers, lakes, streams and creeks. These freshwater ecosystems in the region, are abundantly endowed with fish species such as Clarias gariepinus, Pila ovate, Labeo coubie, Synodontis budgetti and Synodontis eupterus. Apart from the freshwaters, the region also has vast marine ecosystem with abundance of fish species such as Elops lacerta, Mugil cephalus, Thais coronata, Periophthalmus papilio, Tympanotonus fuscatus, and Sardinella maderensis. Unfortunately, many of these fish species are endangered due to constant pollution in the Niger delta regional coastal environment. As a result, it is important to document some available freshwater and marine water fish species which will serve as a reference material for both academics and research institutions, should any of the fish species go into extinction.

CONCENTRATION AND POTENTIAL HEALTH RISK ASSOCIATED WITH DIETARY INTAKE OF SMOKED FISH FROM LAGOS LAGOON

This study assessed the concentration and potential health risk associated with dietary exposure to polycyclic aromatic hydrocarbons (PAHs) in smoked fish products from four fishing communities along Lagos Lagoon, Nigeria. Sixty smoked fish samples obtained from two fish species (Chrysichthys nigrodigitatus and Elops lacerta) which were processed individually with three firewood (Cola nitida, Funtumia elastica and Alchornea cordifolia) were collected from fish processors between October and December, 2018. Samples were subjected to polycyclic aromatic hydrocarbons (PAHs) analysis using gas chromatography-mass spectrometry (GC-MS) and human health risk model analysis. The PAH congeners varied in smoked fish while Pyrene was the most dominant congener in all the fish samples, accounting for more than 70% of the total PAHs. The highest total PAHs levels (2431.85 mg kg-1) was observed in E. lacerta smoked with C. nitida. The Dietary Daily Intake (DDI) values for total and carcinogenic PAHs were higher in E. lacerta smoked with C. nitida and C. nigrodigitatus smoked with A. cordifolia, respectively. Carcinogenic Toxic Equivalent (TEQ) values were lower than the estimated Screening Value (SV) of 12.83 indicating low risk of developing cancer through consumption of assessed smoked fish products. Excess Cancer Risk estimated exceeded the permissible limit (1.0x10−6) set by USEPA. Positive correlations (P<0.01) existed between TEQ and total PAHs, noncarcinogenic PAHs, PAH4, and DDI. This study provides insights into the variation in PAHs level and appropriateness of different fuelwood for smoking similar or dissimilar fish species.

Length-Weight Relationship and Condition Factor of Fish Species Caught by Cast Net in New Calabar River, Nigeria

The length -weight relationship and condition factor (K) of fish species caught by cast net were studied from three stations in the New Calabar River, Rivers State, Nigeria. A total of 1541 specimens of 26 fish species and representing 11 families were randomly collected using cast net with mesh sizes of 1.5 and 2.5 cm. Sample sizes of the different fish species examined in this study ranged from 8.79±0.25 cm (Caranx hippos specie) to 31.48±4.93 cm (Sphyraena barracuda specie) in total length and 15.45±0.40 g (Elops lacerta) to 156.00±39.30 g (Pelmatolapia mariae) in weight. The entire length-weight data in all the three stations were pooled together and the calculated correlation coefficient showed a high positive correlation (1.00) between length and weight of all the fish species except in Caranx hippos (0.18) with low positive correlation. The b value obtained ranged from 2.13 for Ethmalosa fimbriata with negative allomerty to 3.53 for Pelmatolapia mariae with positive allometry. By negative allometry (b < 3), the fish is said to be lighter for its length as it grows and (b>3), the fish gains weight as it grows. The mean condition factor ranged from 0.36 ± 0.03 recorded for Sphyraena barracuda to 2.20 ± 0.02 for Coptodon guineensis and Coptodon zillii. Apart from Sphyraena barracuda general wellbeing of all the fish species were found to be good, as indicated by the values of condition factor, which were nearer to or greater than 1. The results of the present study will provide an effective tool for further studies of population dynamics and stock assessment studies in the study area.

FOOD AND FEEDING HABITS OF SOME FISH SPECIES IN OGUN STATE COASTAL ESTUARY, OGUN STATE, NIGERIA

The food and feeding habits of eight (8) fish species Elops lacerta, Chrysichthys auratus, Schilbe mys-tus, Sardinella maderensis, Synodontis schall, Hepsetus odoe, Tilapia zillii and Mugil cephalus in Ogun estuary, Ogun State, Nigeria were studied and estimated for six months, between February and July, 2014. A total of 470 fishes were randomly collected from the commercial fishermen during the study. Results from the stomach contents analysed using frequency of occurrence and numerical methods showed that S. mystus, E. lacerta, S. maderensis, H. odoe, S. schall, T. zillii, M. cephalus and C. auratus were predators, piscivores, herbivores, piscivores, omnivores, herbivores, herbivores and omnivores respectively while H. odoe and S.mystus partly fed on E. lacerta and T. zillii respec-tively. The Diet Breadth (D) ranged from 0.76 to 0.88 and the percentage Gut Repletion Index (GRI), a reflection of frequency of feeding, ranged between 60-100%.

Concentration and Human Health Implications of Trace Metals in Fish of Economic Importance in Lagos Lagoon, Nigeria.

Background.The most significant sources of food-borne diseases are microbiological and chemical hazards. The health risk due to consumption of food from aquatic ecosystems contaminated with hazardous chemicals including metals has increased globally, especially in developing countries like Nigeria.Objectives.The concentration and human health implications of trace metals in fish of economic importance in Lagos lagoon were investigated by determining the degree of contamination with heavy metals of selected fish from Lagos lagoon and assessing the possible health risks associated with fish consumption.Methods.Fish of economic importance including Caranx hippos, Chrysichthys nigrodigitatus, Elops lacerta, Galeoides decadactylus, Ilisha africana, Liza falcipinnis, Lutjanus goreensis, Mugil cephalus, Pseudotolithus senegalensis, Sarotherodon spp, Sphyraena spp, and Tilapia spp were bought from fishermen fishing in Lagos lagoon. The fish tissue samples were digested and analyzed in five replicates for heavy metals (lead, cadmium, iron, manganese and zinc) using a Varian AA600 atomic absorption spectrometer.Results.There were considerable variations in the concentrations of heavy metals among different species. The twelve fish species collected from Lagos lagoon were found to contain various concentrations of heavy metals and the levels of accumulation of these heavy metals varied across different species. Lead, cadmium, and manganese were present in all the studied fish species at higher concentrations than the maximum allowable concentrations in fish recommended by the Food and Agricultural Organization (FAO) and World Health Organization (WHO). The target hazard quotient (THQ) estimated for individual heavy metals through consumption of different fish species was less than 1 for all individual heavy metal in all the fish species.Conclusions.Controls on the dumping of wastes in the lagoon are needed, along with regular monitoring. Currently, no potential non-carcinogenic health risks from ingestion of a single heavy metal through consumption of these fish species was found.

English

Fish assemblages and their relationship with hydrological variables were investigated in the coastal lagoon of Grand-Lahou (Côte-d’Ivoire) from November 2013 to October 2014. Samplings were carried out by means of artisanal fisheries, once a month, in three sites. A total of 8571 fish belonging to 47 fish species from 25 families were recorded. The most represented families were Cichlidae and Mugilidae with six species. Each environmental variable, notably, dissolved oxygen (DO), temperature and salinity according to the canonical correspondence analysis (CCA) allowed the distinction of two main sectors in the lagoon, associated with three fish assemblages. Sector 1 including sampling sites 2 and 3, characterized by high salinity fluctuations, functioned as a typical estuary. Two fish assemblages identified in this sector were Lutjanus dentatus, Mugil cephalus, Mugil bananensis, Tilapia guineensis and Tylochromis jentenki in station 2 and Sarotherodon melanotheron, Liza falcipinnis and Pomadasys jubelini in station 3. Sector 2 comprising the sampling site 1, characterized by low salinity fluctuation is associated with 11 fish species, notably, Ethmalosa fimbriata and Elops lacerta. The fish assemblage in this sector depends on season, temperature and DO.   Key words: Ichthyofauna distribution, environmental variables, Grand-Lahou lagoon, Côte d’Ivoire.

Fish assemblage structure in the Tropical Coastal Lagoon of Grand Lahou (Cte DIvoire, West Africa)

Fish assemblages and their relationship with hydrological variables were investigated in the coastal lagoon of Grand-Lahou (Cote-d’Ivoire) from November 2013 to October 2014. Samplings were carried out by means of artisanal fisheries, once a month, in three sites. A total of 8571 fish belonging to 47 fish species from 25 families were recorded. The most represented families were Cichlidae and Mugilidae with six species. Each environmental variable, notably, dissolved oxygen (DO), temperature and salinity according to the canonical correspondence analysis (CCA) allowed the distinction of two main sectors in the lagoon, associated with three fish assemblages. Sector 1 including sampling sites 2 and 3, characterized by high salinity fluctuations, functioned as a typical estuary. Two fish assemblages identified in this sector were Lutjanus dentatus, Mugil cephalus, Mugil bananensis, Tilapia guineensis and Tylochromis jentenki in station 2 and Sarotherodon melanotheron, Liza falcipinnis and Pomadasys jubelini in station 3. Sector 2 comprising the sampling site 1, characterized by low salinity fluctuation is associated with 11 fish species, notably, Ethmalosa fimbriata and Elops lacerta. The fish assemblage in this sector depends on season, temperature and DO. Key words: Ichthyofauna distribution, environmental variables, Grand-Lahou lagoon, Cote d’Ivoire.

Effects of hydrographic conditions of ponds on juvenile fish assemblages in the Kakum mangrove system, Ghana

The importance of mangrove ecosystems as nursery grounds for fishes is well established and documented. This paper reports on the possible role of hydrographic dynamics in the selection and utilization of tropical mangrove ponds as nursery habitats for juvenile fishes of ecological and commercial importance. The study was conducted in the Kakum River Estuary mangrove ecosystem near Elmina in the Central Region of Ghana during the peak of the monsoon season. Fish assemblages were sampled using a cast net and a pole seine. Aspects of hydrographic conditions of the ponds were studied. A total of 265 fish specimens, belonging to 18 species and 12 families were sampled. The commonest fish was the blackchinned tilapia Sarotherodon melanotheron, a typical brackish water fish in West Africa, which accounted for 66.4% of the total fish sampled. Ten of the 18 species belonging to 7 families, namely Elops lacerta, Eucinostomus melanopterus, Porogobius schlegelii, Gobionellus occidentalis, Mugil bananensis, Liza falcipinnis, Epinephelus sp., Serranus accraensis, Penaeus notialis and Callinectes amnicola were of marine origin. Spatial and temporal variations in the prevailing hydrographic conditions appeared to influence the fish species composition, density and size classes to varying degrees. Changes in salinity, dissolved oxygen, pH, conductivity and pond size correlated significantly with abundance of juvenile fish. Major fluctuations in fish species composition occurred on a weekly basis with changing pond depth and volume, indicating the dynamic nature of mangroves ponds that may serve the ecological needs of different species over time. Smaller juvenile fishes seemed better adapted to high variations in hydrographic conditions compared to larger juveniles. Higher fish densities and lower species diversity were encountered when the ponds were shallow compared to deep ponds. The utilization of mangrove tidal ponds as nurseries by juvenile fish may therefore be influenced primarily by the salinity and pond size.

Length-weight Relationships of 30 Fish Species in Aby Lagoon, Southeastern Cote d? Ivoire

Most West African lagoons are very productive ecosystems that support important fishery activities. However, increases in human populations put heavy pressure on their resources. This raised the importance of sustainable management tools for these ecosystems. Length-Weight Relationships (LWRs) which is an important fish stock assessment tool was investigated in the Aby lagoon, southeastern Cote d'Ivoire. Fishes were caught monthly from February 2012 through March 2013 using gillnets. Fishes captured were identified, weighted to the nearest gram and standard length was measured to the nearest millimeter. The 30 fish species selected for this study belong to 18 families. The highest species number (n = 7) was recorded for Cichlidae family. All length-weight regressions were significant with a coefficient of determination (r²) varying from 0.462 (Parailia pellucida) to 0.984 (Elops lacerta). Growth coefficient, b of the LWR ranged from 2.229 (P. pellucida) to 3.811 (Eleotris vittata). Nineteen species exhibited negative allometric growth pattern while 11 had positive allometric growth. These results are useful references for West African coastal lagoon management and particularly for that of the Aby lagoon system.

Length-Weight Relationships of Some Economic Fishes of Ibeshe Waterside, Lagos Lagoon, Nigeria

This study describes the length-weight relationships (LWR) and condition factor (K) of six (6) fish species of ecological and economic importance found in Ibeshe waterside area of Lagos lagoon, Nigeria. A total of 154 specimens of Chrysichthys nigrodigitatus , Pomadasy jubelini, Elops lacerta, Cynoglossus senegalensis, Polydactylus quadrifilis and Sphraena piscatorium were collected from the local fishermen during the late rainy period for three months (August 2012 to October 2012) and their total lengths (TL) and weights(W) recorded. A high positive correlation significant at 0.01 levels (2-tailed) exists between the weight and total length of each fish using Pearson’s correlation coefficient (+0.90 to +0.98). The values of constants’ a’ and’ b’ were determined from the length and weight data when transformed into the growth equation: log W=log a+ blog TL. The values of b for the fishes varied from -0.15 to 3.38. The growth pattern of Chrysichthys nigrodigitatus was represented by the equation Log W= 2.24 - 0.15 Log TL, Pomadasy jubelini by Log W = -2.32 + 3.38Log TL, Elops lacerta by Log W = 0.41 + 1.04 Log TL, Cynoglossus senegalensis by Log W = -1.37 + 2.37 Log TL), Polydactylus quadrifilis by Log W = -1.25 + 2.33 Log TL and Sphraena piscatorium by Log W = -1.11 + 2.23Log TL. These values of “b” shows that most of the fishes collected from the Ibeshe waterside of Lagos lagoon displayed negative allometric growth pattern apart from Pomadasy jubelini. The condition factor (K), a reflection of the well-being and degree of fatness ranged from 0.56 in Sphraena piscatorium to 1.62 in Pomadasy jubelini and all these condition factors fall outside the range recommended as suitable for matured fresh water species in the tropics. This might indicate that Ibeshe waterside may be environmentally unfavourable to fishes in the aquatic ecosystem.

Pesticide residues in sediments and aquatic species in Lake Nokoué and Cotonou Lagoon in the Republic of Bénin

Lake Nokoué and Cotonou Lagoon are the most important and most productive continental freshwaters in Bénin, with an estimated fish production of over 2 tonnes per hectare in Lake Nokoué. Organochlorine pesticides are used in agriculture and to repel tsetse flies, malaria mosquitoes and other diseases raised. Sediment, fish, shrimp and oyster species were collected in Lake Nokoué and Cotonou Lagoon for pesticide residues analysis. The main pesticides identified in sediment were pp'-DDT and its metabolites pp-DDE and pp'-DDD, with residue levels between the detection limit and 24.4μg/kg dry weight. Fish species commonly consumed such as Elops lacerta, Podamasys jubelini, Gobbienellus occidentalis, Ethmalosa fimbriata, Mugil cephalus and Hemichromis fasciatus were contaminated with residues of seven to nine pesticides, including pp-DDE, op'-DDD, pp'-DDD, op'-DDT, pp'-DDT, α-endosulfan, aldrin, dieldrin and γ-hexachlorocyclohexane. The levels ranged from detection limit to 289ng/g lipid. The same pesticides were also detected in other aquatic species, such as shrimp and oysters. A summed risk assessment, comparing pesticide intake levels through fish consumption with tolerable daily intake levels proposed by the World Health Organization, showed in all cases a low risk for human health.

Effects of salinity on fish assemblage structure: An evaluation based on taxonomic and functional approaches in the Casamance estuary (Senegal, West Africa)

The utility of taxonomic and functional approaches in assessing the structure of fish communities is tested in the hypersaline estuary of the Casamance river using data from surveys of commercial fisheries conducted between April and July of 2005. Both taxonomic and functional diversity decrease from downstream to upstream regions of the estuary. In terms of species composition, marine-estuarine species (33.3–46.3%, depending on the site) and estuarine species of marine origin (29.3–41.7%) dominate the exploited population in the Casamance estuary. In contrast, the proportion of strictly estuarine species observed upstream is twice that observed downstream.Quantitative analysis based on biomass landed distinguishes two groups in the population: (1) a group of species that is dominant downstream, containing primarily terminal predators and secondary consumers categorised as marine species that are occasional or accessory in estuaries, estuarine marine species, and estuarine species of marine origin; and (2) a group of species characteristic of the upstream region, dominated by a few species (Sarotherodon melanotheron, Tilapia guineensis, and Mugil cephalus) mainly of strictly estuarine and/or herbivorous categories and Elops lacerta, a carnivore fish. The outcomes of the two approaches are similar, and both indicate that the fish community in this estuary is under the influence of strong environmental disturbance. However, the scales at which the specific and functional approaches most reliably reflect environmental conditions are different. The taxonomic approach, i.e., the use of specific biomass is more appropriate at the ecosystem scale and therefore more accessible to local human communities, whereas the functional approach is better suited to regional and sub-regional studies because of the change in species composition from one environment to another.

Diversity of the edible fishes of the Lagos Lagoon, Nigeria and the public health concerns based on their Lead (Pb) content

In this study, a total of eighteen fish species were recorded in the Lagos Lagoon, Nigeria during a one year survey. Among the animals species recorded, the following, Galeoidesdecadactylus, Dentex gibbosus, Elops lacerta, Scomber japonicus, Ethmalosa fimbriata, Lutjanus agennes, Caranx senegallus, Callinectes amnicola, Paeneus notialis and Mytilus edulis were considered to be abundant in the Lagos lagoon based on the frequency of occurrence in fishermen catches. The analysis of the lead content in muscles of the edible fisheries revealed that the animals accumulated measurable quantity of lead in the edible parts. The level of lead detected in most (12 out of 18 species) of the fisheries species were found to be lower than the daily allowable concentration of 2.0 µg/g standard recommended by the World Health Organisation (WHO). Fishes species with high level of lead in their edible parts include Senegal jack, C. senegallus (2.188 µg/g), Bobo croaker, Pseudotolithus elongatus (2.024 µg/g), Cassava croaker, Pseudotolithus senegalensis (3.157 µg/g), crayfish, Penaeus notialis (25.46µg/g), edible mussel, Mytilus edulis (17.69 µg/g) and crab,Callinectes amnicola (10.19 µg/g). The mean levels of lead in Mytilus edulis, Penaeus notialis, and Callinectes amnicola collected from the Lagos lagoon were about 8 to 24 times higher than the WHO daily allowable standards for lead in sea foods and are therefore unsafe for human consumption. The need for regular monitoring of the levels of metals and other contaminants in edible fisheries resources and collaboration between environmental, health and food agencies to avert human tragedies due to lead accumulation are discussed. Key words: Bioaccumulation, lead, industrial pollution, aquatic ecosystem, biomonitoring.

Composition, Diversity and Food Habits of the Fish Community of a Coastal Wetland in Ghana

This study aims at stimulating the scientific community towards a better understanding of fish community ecology in relation to physico-chemical determinants in unmanaged coastal wetlands relevant for informed decision-making on ecosystem functioning and management in the tropical context. We investigated the diversity, size distribution and food habits of the fish community and the abiotic environmental conditions of the Kakum Estuary wetland in Ghana (5o 6' N; 1o 18'W) from July 2009 to February 2010. Eighteen species belonging to 18 genera and 12 families of marine, brackishwater and freshwater fishes were sampled. The poecilid Aplocheilichthys spilauchen (43.31%), the cichlid Sarotherodon melanotheron (18.12%) and the freshwater shrimp Macrobrachium macrobrachion (12.37%) were dominant. Fish communities in pools in the wetland were quite close in diversity (H' ranged from 2.2 to 2.7) and highly similar (Cs > 0.6) possibly as a result of the prevailing similar environmental conditions. Smaller individuals of the cichlids Tilapia zillii, Hemichromis fasciatus and S. melanotheron measuring 2.0-3.9 cm TL, and marine species such as Elops lacerta and Liza falcipinnis measuring 6.0-7.9 cm TL constituted between 60% and 80% of the populations, suggesting the wetland as nursery and feeding grounds for the fishes. Examination of stomach contents showed that the communities included detritivorous, planktivorous, insectivorous, omnivorous and piscivorous species. It is strongly recommended to restrict fishing in the wetland during the wet season to avoid exploitation of juvenile fishes which use the wetland as nursery and feeding grounds during that period.

Growth patterns, diet composition and reproduction in the ten pounder, Elops lacerta from Ologe lagoon, Lagos, Nigeria

Ten pounder, Elops lacerta, a member of the family Elopidae is a tropical and subtropical fish species. Growth patterns, food and feeding habits and reproduction of 317 specimens of E. lacerta were investigated in Ologe lagoon, Lagos, Nigeria. Diurnal and nocturnal fishing activities were carried out in the lagoon using cast and gill nets. The specimens examined ranged from 90375mm total length (TL) and weighed 4.7214g body weight (BW) respectively. Of the specimens 49.5% were juveniles, 36.3% fingerlings and 14.2% adults. Specimens were classified as unsex, males and females their growth exponential “b” values were allometric and 2.40, 2.27 and 2.27 respectively meaning the fish become lighter for its length as it grows. These values accounted for the robustness of the fish in Ologe. High correlation coefficient was observed in E. lacerta with r=0.76, 0.97, and 0.88 for unsex, male and female specimens respectively. 158 males and 64 females were caught giving 1male:0.41female sex ratio. This was significantly different (P>0.05) from the expected 1male:1female. Diet of the fish consisted of shrimps, plant materials and unidentified food mass. Presence of fish and shrimps in stomachs of the fish indicated its piscivorous and predatory tendency while plant materials connoted its herbivorous habit.