It is not what you know, but what you don't know:Genetic analyses reveal a small unknown eastern North Atlantic breeding population of humpback whales

• Main Authors: Bérubé, Martine, Øien, Nils, Robbins, Jooke, Vikingsson, G.A., Jorgensen, H, Sellas, Anna, Larsen, Anja, Palsboll, Per
• Format: Conference Object
• Language: English
• Published: 2009
• Subjects: Norway; Humpback Whale; Iceland; North Atlantic; Northeast Atlantic
• Online Access: https://hdl.handle.net/11370/eb5e6160-2ddc-4b97-9537-f4997b5917b7; https://research.rug.nl/en/publications/eb5e6160-2ddc-4b97-9537-f4997b5917b7

Humpback whales in the North Atlantic are known to winter in the Caribbean as well as off western Africa at the Cape Verdes Islands. Photographic matches have been reported for individual humpback whales photographed in northeastern North Atlantic waters to the Caribbean and Cape Verde Islands. These observations show that humpback whales summering in the Northeast Atlantic winter at both breeding grounds. We genotyped 20 microsatellite loci in 1530 humpback samples from the Gulf of Maine, Iceland and Norway. Individual-based analyses revealed that about 90% and 50% of the humpback whales summering in the central and northeastern North Atlantic, respectively, are not part of the Caribbean breeding population but breed elsewhere. The current abundance estimates of humpback whales in the northeastern and central North Atlantic, as well as off the Cape Verde Islands, indicates that only a small fraction of the humpback whales summering in the Northeastern Atlantic winter off the Cape Verde Islands. This observation was further corroborated by estimations of abundance inferred from the proportion of close kin among the individuals allocated to the "Caribbean" and "northeastern North Atlantic" breeding population. In conclusion, our results point to the existence of a second unknown humpback whale breeding ground in the North Atlantic, which numbers substantially fewer individuals than the Caribbean breeding population. Past and ongoing monitoring of abundance in the Caribbean breeding population show this population is increasing. However, the "northeastern North Atlantic" breeding appears to be much smaller and thus locating and monitoring this population need be prioritized.