Ingestion and utilization of periphyton grown on artificial substrates by Nile tilapia, Oreochromis niloticus L.

摘要

The study was carried out to quantify the periphyton biomass developed on glass substrates over time, to investigate the effects of periphyton quantity and fish size on the ingestion rate by fish, and to determine the feed conversion ratio (FCR) of periphyton by tilapia Oreochromis niloticus. Periphyton was grown in two fertilised 1000-1 tanks on glass slides and monitored as dry matter (g), ash-free dry matter (g) and chlorophyll a concentrations (mg) per unit surface area (M) over a six week period. Ingestion rate was determined for two sizes of tilapia (7 and 24 g) which were provided with four different periphyton densities. Determination of FCR was made after feeding three individual fish ad libitum with periphyton for two weeks.