SC/69A/NH/05  

Document Number

SC/69A/NH/05

Full Title

Ocean-basin-wide movement patterns of North Atlantic humpback whales, Megaptera novaeangliae

Author

Jones, Allen, Basran, Berrow, Betancort, Bouveret, Boye, Broms, Chosson, Clapham, Fernald, Frediani, Jann, Kempen, López Suárez, Magnúsdóttir, Mattila, Mackay, Øien, Rasmussen, Rinaldi, Robbins, Sears, Seton, Simon, Stevick, Weinrich, Wenzel, Whi...

Authors Summary

Jones et al. present a re-evaluation of the spatial structuring of the North Atlantic humpback whale population on an ocean-basin scale. Larger sample sizes now available throughout their range and regional changes in their spatial patterns in the North Atlantic necessitate a re-evaluation and expansion of past movement analyses. Jones presents a quantification of the ocean-basin-wide movement patterns of humpbacks from 1980 through 2015 from collections contributed to the North Atlantic Humpback Whale Catalog, a dataset of 37,259 photographic-identification images of 9,566 individual whales from all North Atlantic breeding and feeding regions. Transition probabilities between all major feeding and breeding/calving areas were estimated to detect differences between breeding regions. These analyses further divided the West Indies into two distinct breeding populations: the Greater and Lesser Antilles. Breeding-to-feeding area transition probabilities were highest from the Greater Antilles to western feeding grounds (Gulf of Maine, Atlantic Canada and West Greenland), from the Lesser Antilles to eastern feeding grounds (Norway and Iceland), and from CVI to eastern feeding grounds. Migratory patterns between feeding areas and the Lesser Antilles were more similar to those from the CVI breeding segment than the geographically closer area in the Greater Antilles, suggesting that humpbacks from these two regions within the West Indies are behaviorally distinct and may best be managed as such.

Publisher

IWC

Keywords

Publication Year

2023

Abstract

The spatial structure of the North Atlantic humpback whale population has not been studied on an ocean-basin scale in three decades. Larger sample sizes now available throughout their range and regional changes in their spatial patterns in the North Atlantic necessitate a re-evaluation and expansion of past movement analyses. Additional information on the movements and population spatial structure of humpbacks across the North Atlantic Ocean basin is needed considering their various listing statuses under the International Union for the Conservation of Nature, United States’ Endangered Species Act (ESA) and International Whaling Commission. Within the North Atlantic, one subpopulation off the Cape Verde Islands/Northwest Africa (CVI) is currently considered endangered under the ESA, while the other subpopulation, breeding/calving in the West Indies, is not considered at risk. The work presented here quantifies the ocean-basin-wide movement patterns of humpbacks from 1980 through 2015 from collections contributed to the North Atlantic Humpback Whale Catalog, a dataset of 37,259 photographic-identification images of 9,566 individual whales from all North Atlantic breeding and feeding regions. Transition probabilities between all major feeding and breeding/calving areas were estimated to detect differences between breeding regions. Based on emerging trends, our analyses further divided the West Indies into two distinct breeding populations: the Greater and Lesser Antilles. Breeding-to-feeding area transition probabilities were highest from the Greater Antilles to western feeding grounds (Gulf of Maine, Atlantic Canada and West Greenland), from the Lesser Antilles to eastern feeding grounds (Norway and Iceland), and from CVI to eastern feeding grounds. Migratory patterns between feeding areas and the Lesser Antilles were more similar to those from the CVI breeding segment than the geographically closer area in the Greater Antilles, which suggests that humpbacks from these two regions within the West Indies are behaviorally distinct and may be best managed as such.