Food and feeding habits and condition factor of fish species in Qua Iboe River estuary, Akwa Ibom State, southeastern Nigeria

Abstract

Food and feeding habits of 187 fish specimens made up of 17 species from Qua Iboe River estuary were studied from July – October 2008. Specimens with food were more (141; 75.40%) than those without food (46; 24.60%). Highest condition factor was obtained in Chrysichthys nigrodigitatus (2.71) while the least was found in Sarotherodon barracuda (0.37). Gastrosomatic index showed highest (100%) in eight species whereas the lowest occurred only in Trachinotus teraia (4.35%). The highest relative frequency of food items was observed in fish and sediments (10; 15.63%) while the lowest occurred in annelids, molluscs and unidentified foods (1; 1.56%). Others were crustaceans and detritus (8; 12.50%), algae and plant materials (7; 10.94%), nematodes (5; 7.80%) and protozoans and insects (3; 4.69%). Variation in food richness ranged from 1 food item (0.54%) in three species (Bathygobius soporator, Epinephelus aeneus and T. teraia) to 36 food items (19.67%) observed in Liza falcipinnis. In view of these diets, the fishes were subdivided into planktophaguous, herbivorous, predatory and detritivorous species. However, overlaps existed; fishes were found to feed on more than one type of food item which reduced competition and encouraged coexistence.