DIEL CHANGES IN FOOD AND FEEDING OF SMALL GADOIDS ON A COASTAL BANK

In 1991, diel changes in foraging activity and dietary composition of haddock (Melanogrammus aeglefinus L.), Norway pout (Trisopterus esmark i Nilsson) and poor-cod (Trisopterus minutus L.) were investigated. Th e fish were sampled from 14 consecutive trawls over 48 h in two areas; one 75 m, the other 140 m deep on a coastal bank off south-western No rway. Four predator groups were delimited based on length-specific die t composition and diel changes in length distributions: haddock (15.0- 25.9 cm), small (11.0-14.9 cm) Norway pout, and large (15.0-19.9 cm) N orway pout and poor-cod (13.0-26.9 cm). Diel variation in dry weight o f the stomach was found for all groups except the large Norway pout. I n particular, both between-day and between-prey differences in the die l patterns were observed. In July, haddock were eating polychaetes and isopods, mainly in the early morning and from noon until a few hours after sunset. The small Norway pout were feeding on copepods, mostly i n the middle of the day, while poor-cod were feeding on decapods, isop ods and polychaetes mainly at night. (C) 1995 International Council fo r the Exploration of the Sea