Some aspects of the feeding ecology of myctophids in the waters off central east Africa. In: Flødevigen rapportserie no 1, 1988

Abstract

Analyses of the degree of filling and the state of digestion of four species (Diaphus watasei, Benthosema fibulatum, Myctophum brachygnatum and Diaphus garmani) revealed that all but D. watasei were cyclic feeders feeding at or near the surface during the night. Diaphus watasei was an acyclic feeder feeding close to the bottom. Prey analysis of 14 myctophid species showed that crustacea, mainly copepods, was the main food. Molluscs and bivalve larvae, larvaceans and salps, chaetognaths and polychaetes were also eaten. For Diaphus watasei, euphasiids, squids (family Onychoteuthidae), fish and fish larvae (family Myctophidae), contributed a great deal. All but three species were opportunistic feeders. Diaphus nielseni, Diaphus jenseni (both feeding specifically on copepods) and Myctophum brachygriatum (feeding specifically on molluscs and bivalve larvae) were selective feeders. The myctophids showed food partitioning by feeding at different depths, on selected sizes and selected taxa. Ontogenetical resource partitioning was also observed. They were visually oriented predators and the maximum prey size seemed to be determined by the size of the jaw. They seemed to catch individual prey items and swallow them whole.