Department of Fisheries and Aquaculture, University of Uyo, Uyo, Nigeria
Ekwu, A.O., Department of Fisheries and Aquaculture, University of Uyo, Uyo, Nigeria
The fecundity, egg size and gonadosomatic index (GSI) of some commercially important ichthyofaunal species from the Cross River coastal waters was investigated after an oil spill. There was significant reduction in fish landings compared with catches prior to the oil spill. Mean fecundity values ranged from 1596 eggs to 2581 eggs for chrysichthys nigrodigitatus; 1538 eggs to 2300 eggs for Heterobranchus bidorsalis; 1020 eggs to 1460 eggs for Clarias gariepinus; 138 eggs to 320 eggs for Oreochromis niloticus; 1415 eggs to 2039 eggs for Chrysichthys auratus, 1824 to 2341 eggs for Heterobranchus niloticus and 108 to 155 eggs for Tilapia galilea. The mean, GSI values ranged from 15.28 to 18.6 for Chrysichthys nigrodigitatus; 13.0 to 17.6 for Heterobranchus bidorsalis; 12.58 to 13.6 for Heterbranchus niloticus; 7.2 to 8.71 for Oreochromis niloticus; 12.28 to 14.9 for Clarias gariepinus; 13.2 to 14.75 for Chrysickthys auratus and 5.5 to 5.8 for Tilapia galilea. The oil spill also affected the egg size, which varied between 1.5mm in chrysichthys nigrodigitatus and 3.3mm in Oreochromis niloticus, across the sampling stations. Fecundity and GSI values were much lower than expected, being the onset of the breeding season. Copyright © Enviromedia.