Ocean Wanderers: Extralimital Encounters with Bowhead Whales (Balaena mysticetus) in Temperate European Shallow Waters

Abstract

Reports of bowhead whales (Balaena mysticetus) outside the Arctic Circle are scarce. On 15 May 2016, a juvenile bowhead whale was recorded in shallow water in Mount's Bay (Cornwall, UK) much further south than the species' normal dis- tribution. Fifteen months earlier, another such sighting was made involving a juvenile bowhead whale in the shallow water of an offshore island, St Martin's (Isles of Scilly, Cornwall), only 60 km from Mount's Bay. Other observations of suspected/confirmed immature bowhead whales include (1) an unconfirmed sighting involving a whale without a dorsal fin off Cornwall (13 May 2016), (2) a confirmed sighting off France (10 May 2016), and (3) a confirmed sighting in Carlingford Lough (border of Northern Ireland/ Republic of Ireland; 29 May 2016). These extra- limital encounters present the first confirmed sightings of bowhead whales within temperate European waters. Apart from the whale sighted in 2015, the sightings in 2016 probably all involve the same juvenile whale. Indeed, photographs depicting natural scars/marks suggest that the Carlingford Lough bowhead whale is the same individual as the Mount's Bay. The whale was displaying behaviour indicative of ram feeding in a sheltered, shallow bay (< 10 m water depth). Do these records present vagrant animals from nearby endangered Arctic stocks? Whatever trig- gered these immature bowhead whales to venture well outside the Arctic Circle remains unknown, yet these observations suggest an unexpected adaptability to foraging in temperate shallow waters.