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

摘要

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 90- 375mm total length (TL) and weighed 4.7- 214g 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.