Accounting for Diel Feeding Periodicity in Quantifying Food Resource Partitioning in Fish Assemblages in Three Reservoirs of Sri Lanka

Abstract

Most investigations on food resource partitioning in fish along the temporal dimension are based on the diet composition of constituent species in fish assemblages, pooled over a longer time lapse, but variation within 24-hour cycle is not considered. In the present study, an attempt was made to account for diel feeding periodicity in fish species in quantifying dietary overlaps among constituent species in fish assemblages in three reservoirs of Sri Lanka. The dietary overlap of fish species estimated as a mean for short time intervals in three reservoirs is significantly lower than that is based on the sum of all time intervals, especially for pairs with moderate and high overlaps. Furthermore, the dietary overlaps estimated for short time intervals, which indicate moderate and high dietary overlaps between pairs, exhibit negligible overlaps of peak feeding period indicating the necessity to account for diel feeding periodicity in quantification of food resource partitioning.