BIOMETRICS AND FEED UTILISATION OF ARTIFICIALLY SPAWNED Heterobranchus longifilis VALENCIENNES, 1840

Abstract

The biometrics over a 22-week culture period of juvenile Heterobranchus longifilis was investigated with a view to
determining levels of feed utilization within a commercial scale concrete pond cum water recirculation production
system. The standard length, total length and weight of individual sampled fish were measured fortnightly with the
aid of a measuring board for length determination and a digital Acculab 300-electronic balance for the latter,
throughout the exercise. Negative allometry was observed with respect to the linear relationship between fish
standard length and total length. While, that between fish weight and standard length showed a positive allometric
growth pattern represented by weight (g) = -216.98 + 27.65x. Heterobranchus longifilis is an efficient utilizer of
feed recording a live weight gain of 3.51g for every 1g of feed consumed. This is further evidenced by a growth
utilization of feed value of 0.28 and mean condition factor of 1.7 obtained. Heterobranchus longifilis has
significantly high survival and growth potentials. Growth rate though of genetic basis is influenced by feed
accessibility and utilization.