Orca’s Orcinus orca en Grienden Globicephala melas bij trawlers ten oosten van Shetland

An account is given of the behaviour of Killer Whales Orcinus orca and Pilot Whales Globicephala melas near trawlers, to the northeast of Shetland. Around 30-40 Killer Whales and at least 80 Pilot Whales were present near 10 midwater freezer trawlers fishing on large shoals of Mackerel Scomber scombrus. The Killer Whales were scavenging on discards. The contribution of discards in the diet of Killer Whales around Shetland is discussed. Scavenging on discards by Pilot Whales has not been observed, but the animals came very close to the ship while showing play behaviour on at least one occasion. Pilot Whales were twice seen chasing Killer Whales at high speed.