Clearance rates of suspended particulate organic carbon by Nile tilapia with a dual pattern of filter feeding

Abstract

The filter-feeding activity of Nile tilapia, Oreochromis niloticus L., was observed during a 24-h feeding cycle for five consecutive days. The feeding activity was high from afternoon to midnight, with a peak after dusk, and lowest from midnight to morning. The clearance rate of cyanobacteria dominated water was estimated during the low morning and high evening feeding periods. The tilapia cleared 34 mg C/l suspended particulate organic carbon in 4.5 h during the reduced morning period (beginning 07:00) and 45 mg C/l in 1 h during the peak evening period (beginning 20:30). Clearance rates of the cyanobacterial water were 13.4±1.2 l/kg fish/h in the morning and 66±3.6 l/kg fish/h in the evening.