Rohu Labeo rohita (Hamilton, 1822) changes feeding strategy throughout its ontogeny An explanation from feeding ecology

Abstract

Labeo rohita is a popular Indian major carp species in carp polyculture practice. It is known as water column feeder which feeds on plankton. In the juvenile and adult stages rohu is essentially an herbivorous column feeder, preferring algae and submerged vegetation. Under natural condition, in fingerling stage, it prefers zooplankton, with phytoplankton as subsidiary food. At this stage it exhibited a strong positive selection for all zooplanktonic organisms and smaller phytoplankton. Adults show a strong negative selection for all zooplanktonic organisms and positive selection for most phytoplanktonic organisms. However, in periphytic environment, it ingests sub-periphytic organisms present in proximity to substrate. In conclusion, it is agreed that L. rohita exhibits different feeding strategy during its growth from fingerling to adult and also from planktonic to periphytic environment. Adoption of a fish culture strategy according to its differential feeding strategy would maximize in converting naturally available resources to fish biomass especially in polyculture practice.