Segregation of migration by feeding ground origin in North Atlantic humpback whales (Megaptera novaeangliae)

Abstract

Results from a large-scale, capture-recapture study of humpback whales Megaptera novaeangliae in the North Atlantic show that migration timing is influenced by feeding ground origin. No significant differences were observed in the number of individuals from any feeding area that were re-sighted in the common breeding area in the West Indies. However, there was a relationship between the proportion (logit transformed) of West Indies sightings and longitude (r 2 = 0.97, F 1,3 = 98.27, P = 0.0022) suggesting that individuals feeding farther to the east are less likely to winter in the West Indies. A relationship was also detected between sighting date in the West Indies and feeding area. Mean sighting dates in the West Indies for individuals identified in the Gulf of Maine and eastern Canada were significantly earlier than those for animals identified in Greenland, Iceland and Norway (9.97 days, t 179 = 3.53, P = 0.00054). There was also evidence for sexual segregation in migration; males were seen earlier on the breeding ground than were females (6.63 days, t 105 = 1.98, P = 0.050). This pattern was consistently observed for animals from all feeding areas; a combined model showed a significant effect for both sex (F 1 = 5.942, P = 0.017) and feeding area (F 3 = 4.756, P = 0.0038). The temporal difference in occupancy of the West Indies between individuals from different feeding areas, coupled with sexual differences in migratory patterns, presents the possibility that there are reduced mating opportunities between individuals from different high latitude areas.

Migratory round-trip of individually identified humpback whales at the Strait of Magellan: clues on transit times and phylopatry to destinations

“…Our information and those previously published for the Antarctic Peninsula (Stone et al 1990, Stevick et al 2004 show that the southeastern Pacific humpback whale population may segregate into at least two separate feeding areas located at variable distances from the breeding region, resembling the north Atlantic and north Pacific humpback whale populations, where some geographically distinct feeding aggregations have been described (Baker et al 1986, Katona & Beard 1990, Katona & Beard 1991, Stevick et al 2003. Taken together, our results suggest for Area I stock the existence of a shorter migratory cycle, with final summer destinations at SM, 1,400 km closer than the previously described at WAP.…”

Satellite-monitored movements of humpback whales Megaptera novaeangliae in the Southwest Atlantic Ocean

“…Humpback whales Megaptera novaeangliae inhabit all major ocean basins and undertake the longest migrations of any mammal (Stone et al 1990, Stevick et al 2003. Currently, 7 geographically separated populations (labelled breeding stocks A to G) are recognized by the International Whaling Commission (IWC) in the wintering grounds in the Southern Hemisphere (IWC 1998).…”

Genetic evidence for sex-specific migratory behaviour in western South Pacific humpback whales

“…In the North Atlantic for example, whales from all known summering areas migrate to one wintering area, the Caribbean, (although some also migrate to the Cape Verde Islands; Jann et al 2003). Whales from the Barents Sea, that must make the longest migration to the Caribbean, appear less likely to migrate than others (Stevick et al 2003). In the eastern South Pacific, humpback whales that summer in Antarctic waters migrate across the equator to wintering grounds in Central America (Rasmussen et al 2007), apparently in response to a lack of suitable southern breeding habitat.…”