Biodiversity and Abundance of Shell Fish in Akor and Itu Rivers of Niger Delta Region, Nigeria

Abstract

Shellfish are important source of protein and essential amino acids. There are no regulations of shellfish exploitation in Nigeria leading to overfishing loss of species due to oil pollution especially in the Niger delta region. There is paucity of information on shellfish biodiversity in Niger delta region Nigeria. A survey on the biodiversity of shellfish of Akor River, Itunta Ibere Ikwuano Local Government Area Abia State and Itu River in Itu Local Government Area of Akwa Ibom State both in Nigeria. There were three sampling stations per river covering upper river, midriver and lower river sections. The shellfishes were caught with caught with traps and handpicked from the rivers over a period of 18 months. There were two species of mussels Aspatharia dahomeyensis and Margaritifera margaritifera, caught within the period. The periwinkles that were caught, were Tympanotonus fuscatus, and Pachymelania aurita. Pachymelania aurita was specifically found at Itu River alone. The freshwater shrimp, Macrobrachium macrobrachion and Macrobrachium vollenhoveni were the two species of shrimp caught on both rivers during the period of the experiment. The species of clam found in the rivers was Galatea paradoxa. There was only one species of fresh water oyster found at Itu river and this was Crassostrea gasar. There was no fresh water oyster found at Akor river. At Akor River, two species of snail; Melanoides Maculata and Pila ovata were obtained. The weight of crabs obtained at Akor and Itu Rivers were 35.64±11.67g and 31.81±10.71g respectively. Prawns gotten from Akor River weighed 22.32±24.97g and Itu River was 46.39±16.02g. Mussels weighed 4.74±5.10g and 8.66±3.00g at Akor and Itu river respectively. Periwinkle obtained from Akor River was 0.36±0.44g and 0.53±0.35g at Itu River and oyster 33.89±11.00g. Results shows that shell fishes are dominant in both Akor river and Itu river. Results also show some shellfishes that have normally been caught in marine and brackish water ecosystem, can now be found in the fresh waters of the Niger delta, probably due to migration, climate change or tidal systems.

Key words; Biodiversity, Abundance, Shellfish, Akor River, Itu River