Occurrence and distribution of micro-crustaceans in cross river estuary, Niger delta region, Nigeria

Abstract

Present Studies were conducted on the occurrence and distribution of micro-crustaceans in Cross River Estuary, Nigeria between August and October, 2014. The study was aimed to determine the abundance and diversity of micro-crustaceans in the Estuary. A total of 145 individuals of micro-crustaceans belonging to ten (10) taxonomic groups (Copepods, Crustacean larva, Isopoda, Ostracoda, Euphausiids, Acartidae, Cladocera, Harpacticoida, Sinus larva, and Mysidacea) were recorded during the sampling period. The order of dominance followed the pattern: Copepods > Crustacean larva> Isopoda>Ostracoda> Euphausiids and Acartidae>Cladocera> Harpacticoida and Sinus larva>Mysidacea. Abundance was observed to be higher in surface water, with a total of 51 micro-crustaceans (35.17 %), followed by 48 micro-crustaceans in muddy shore (33.10 %) and lowest in sandy shore with 46 micro-crustaceans (31.72 %). The higher numerical abundance observed in the surface water compared to muddy and sandy bottom was linked to nature of feeding of micro-crustaceans and favorable ecological conditions in the surface water. There was no significant variation (P