FISH ABUNDANCE AND DISTRIBUTION OF THREE WATER BODIES
Fish abundance and distribution of three water bodies namely Onah lake, Anwai river and River Niger at cable point was studied. Fish specimens were collected using gill nets, traps, and hook and line between July-December, 2013.. One thousand four hundred and eighty seven fish specimens were collected and brought to the laboratory at Delta state university for further identification using identification key. The family Mochokidae was the most abundant with 441 individuals from the three sampling stations followed by Cichlidae with 374 individuals. The least represented families were Notopteridae and Dasyatidae with 3 individuals each. On the species level, Oreochromis niloticus had the highest number with 118 individuals followed by Synondontis occeilifer with 104 individuals, while the least representation were Hemichromis bimaculatus and Aechenoglanis biscutatus with 1 individuals each. The rich assemblage of fish species collected indicates that these waterbodies have the potential for fish production if properly managed. It is hoped that the information gathered will be useful for future planning and management of the fisheries resources of Onah lake, Anwai river and River Niger at Cable point.
Fisheries resources are on the reduction in Nigeria due to over exploitation and inadequate management of her coastal waters (Lawson and Olusanya, 2010). For sustainability of these resources, an adequate knowledge of species composition, relative abundance of her water bodies must be understood and actively pursued (Lawson and Olusanya, 2010). Different species in a given area is the fundamental unit in which to assess the homogeneity of an environment and community used in conservation studies to determine the sensitivity of the ecosystems and their resident species while rare species is relative to other species in a given community and are usually describe for a single tropic level (Lawson and Olusanya, 2010).
Nigeria is blessed with abundant natural aquatic resources in Marine, Estuarine and Freshwater environments. The freshwater components are within extensive river systems, lakes, flood plans and reservoirs scattered over the entire land surface area of over 4,212, 500ha (Ita, 1993) as cited by (Obasohan and Oransaye, 2006). Nigeria also has (8) coastal states namely; Ogun State, Lagos State, Ondo State, Delta State, Bayelsa State, Akwa-Ibom State and Cross River state. The fish fauna of the Nigerian freshwater system has been the focus of research for quite sometimes. Some of the researcher are Welman (1984); Banks et al., (1965); Akinyemi (19850; Idodo-umeh (1987) and Ita (1987). These studies concentrated more on rivers, with less attention on the lakes and wet lands yet they produced a variety of reports on the Nigerian Freshwater.