Studies on the deep-water pelagic community of Korsfjorden, Western Norway. The dry weight and calorie content ofEuchaeta norvegica(Copepoda),Boreomysis arctica(Mysidacea), andMeganyctiphanes norvegica(Euphausiacea)

Abstract

The weight and calorie content of various stages of Euchaeta norvegica and of its egg sacs are given, based on fresh material obtained at various times of year. Monthly samples show that adult females are heavier and have a higher calorie content in the autumn/winter than in spring/summer. This is not reflected in any difference in egg size or calorie content. Both generations show fluctuations which may be associated with maturation and spawning. Length/weight relationships are described for male and female Boreomysis arctica. Spent females (with an empty brood pouch) are 24–33 % lighter than maturing females (without an expanded brood pouch). The caloric value varies little with body length over the observed size range. Monthly analyses of spent females within a restricted size range gave higher weights and caloric values between July and February than between March and June. Length/weight relationships are described for Meganyctiphanes norvegica sampled in two winter seasons and one summer. On only one of these occasions (winter) did caloric value clearly increase with size, though the smallest specimens always tended to be low in calories. Monthly analyses of males and females within a restricted size range showed seasonal variation in dry weight and caloric value between the lowest values in March/April and a peak in December.