A note on common minke whale (Balaenoptera acutorostrata) diets in the Norwegian Sea and the North Sea

Abstract

Visual observations and quantitative samples of forestomach contents were made of minke whales caught in the Norwegian Sea (15 visual observations in 1999, 8 in 2000 and 1 stomach sample) and North Sea (15 visual observations and 7 stomach samples, all from 1999). Prey species were identified, and from the forestomach samples, each prey’s relative contribution by weight to the diet was calculated. In the Norwegian Sea, the diet was dominated by Norwegian spring-spawning herring (100%). This was consistent with the large and dominant abundance of herring in the area. Observations and forestomach samples from the North Sea indicated a more varied diet, with sandeel (Ammodytes spp.) contributing 86.7% to the diet by weight, followed by mackerel (9.3%), whiting (2.4%), herring (1.1%) and Norway pout (0.5%). Haddock was observed in one stomach, but was not found in any of the samples. Sandeel occurred in all observed and four of the sampled stomachs. The domination of pelagic species in the diet strongly indicates pelagic feeding behaviour in both areas.