Some aspects of the biology of banded jewel fish, Hemichromis fasciatus (Peters, 1857) in River Orogodo, Delta State, Nigeria
The cichlid, Hemichromis fasciatus (Peters, 1857) commonly called banded jewel fish is an ornamental fish which occurs in various freshwater bodies in Africa. Some aspects of the ecology of this fish species was investigated in River Orogodo, Delta State, a first order stream, during the dry and rainy season, between January 2006 and December 2007. Fish samples caught, were preserved in 10% formalin, identified, and the morphometric measurements taken. The food and feeding habits were studied using the frequency of occurrence and point methods. H. fasciatus occurred in the entire stretch of the river throughout the year with peak abundance during the rainy season. It was a dominant cichlid (29.78% by number and 20.67% by biomass) in River Orogodo. Its standard length ranged from 3.10 to 14. 60 cm (mean=9.70 cm± 0.2) and weighed 6.10 to 81.00 g (mean=37.12 g ± 1.4). The growth pattern was negative allometric (b<3). Condition factor (K) ranged from 2.00 to 3.60 and increased with individual length of fish irrespective of sex. The adult size class (9.00-15.00 cm) had higher condition factor (K) in both sexes. The condition factor showed seasonal fluctuation with peak values in the rainy season months of May to August each year. Food items consumed included chironomid larvae, mosquitoe larvae, ephemeropteran nymph, fish fry and detritus. The species were fed at both day and night. Percentage of empty stomach showed maximum values (>5%) between January and February, November and December each year while feeding intensity was highest (>15%) between August and October. The dominant status of H. fasciatus in River Orogodo, which are its good condition and the wide food spectrum available to it could be harnessed for its improved fisheries management and conservation in the area.
Keywords: Hemichromis fasciatus, River Orogodo, food and feeding habits, growth.