Feeding behaviour of Diaphus dumerilii in NW Africa with notes on its relations to other myctophids in the area. In: Flødevigen rapportserie no 1, 1988

Abstract

The feeding pattern of D. dumerilii was studied based on material collected by R/V "Dr. Fridtjof Nansen" from west Africa (from Mauritania to Nigeria-Congo area and the Cape Verde Islands) in 1981. The other species. Diaphus dumerilii, D. taaningi, Myctophum affine and M. nitidulum from the same area were studied for comparison. In D. dumerilii, copepods were the main forage item while crustacean larvae ranked second in abundance. Euphausiids. larvaceans and salps were also important in the diet. Molluscs, fish. fish larvae and amphipods were less frequently observed. Polychaetes and chaetognaths were rarely found. It is suggested that this species generally is an opportunistic feeder, although it may show a preference for prey species having conspiciuous eye pigmentation (i.e. euphausiids), body colour (i.e. crustacean larvae) or other conspiciuous features (i.e. pigmented spot on the side of cephalothorax in the copepod Pleuromamma). They also seem to select prey taxa with sizes of 1.5-3.5 mm. D. dumerilii also showed a tendency for the larger fish to take larger prey items than the smaller fish. Comparison of the diet of D. dumerilii with that of D. taaningi and Myctophum nitidulum and M. affine showed that these species had different feeding patterns.