Killer whales (Orcinus orca)

Marine mammals 2013
Typography
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Killer whales occur in all world oceans and most seas, but their relative scarcity and sporadic occurrence make them difficult to census in the Barents Region. Photo-identification techniques have been used to recognise >400 individuals in northern Norway. Coastal killer whales are tightly linked to the availability of herring. During winter, killer whales aggregate in and around Vestfjorden in Lofoten, foraging on over-wintering herring. 

However, during that last few years herring have overwintered outside the fjords in the Norwegian Sea, which has greatly reduced coastal sightings in the Vesfjorden area. Surveys conducted in 1989 in the northern North Sea and eastern Norwegian Sea north to Bear Island suggest ~7,000 animals in this area. Killer whales have been sighted with increasing frequency in Svalbard waters in recent years, usually at the shelf edge, and in 2008 were observed as early as March at close to 80o N (NPI Marine Mammal Sighting Data Base). Along the coast of Norway, several cases of killer whale predation on harbour and grey seals have been reported in recent years. There are also recent reports of killer whales feeding on harp seal pups in the West Ice area (Foote et al., 2013). Genetic analyses suggest that these mammal-eating killer whales belong to populations that were thought to be strictly piscivorous. This may suggest a shift in killer whale feeding patterns that may have significant effects on seal populations in the Northeast Atlantic.