Food and feeding habits, condition factor and length-weight relationships of Mugil cephalus and Pseudotolithus elongatus in Cross River estuary,Cross River State, Nigeria

Abstract

A study of the diet of Mugil cephalus and Pseudotolithus elongatus from Calabar Estuary in Calabar was carried out between the months of December 2007 to March 2008 at Nsidung Beach, a tributary of Calabar estuary, Cross River State, Nigeria to understand some aspect of food and feeding habits of these selected fish species. The stomach contents of each of forty samples caught from the Beach by Artisanal fishers were examined. While M. cephalus was predominantly phytophagus and benthic, P. elongatus was omnivorous tending towards piscivory and benthic. They exhibited little variations in the food items with regards to fish size and age in both species. M. cephalus had 1.26% Ostracod, 0.01% nemata, 0.14% pisces scales, 2.64% Chlorophyceae and 95.94% diatoms at adult stage; 99.95% diatoms at juvenile; 99.98% diatoms and 0.017% nemata at sub-adult. P. elongatus had 0.5% Nemata, 45.5% dryopid larvae, 2.75% may fly larvae, .1.75% copepod, 0.5% Lepidoptera, 35.25% diatoms, 35% fish eggs, 9.75% ctenoid scales, 1.5% ostracod, and 0. 25% empty stomach in sub-adult guts. Adults of P. elongatus had 14.81% diatoms, 46.30% fish scales, 37.04% fish eggs, 3.7% each of may fly, copepod legs and dryopid larvae and 1.85% nemata. The LWR using standard length measurement for both species had lower allometry (2.734, 2.823) than those with total length (3.001, 3.145), respectively, for M. cephalus and P. elongatus. The condition factors of 0.946 and 1.006, respectively, were realized for M. cephalus and P. elongatus while the coefficients of determinations (r²) were 0.996 and 0.897.

Key words: Mugil cephalus, Pseudotolithus elongatus, food, condition factor.