Site fidelity, population identity and demographic characteristics of humback whales in the New York Bight apex

Abstract

Humpback whales (Megaptera novaeangliae) exhibit maternally driven fidelity to feeding grounds, and yet occasonally occupy new areas. Humpback whale sightings and mortalities in the New York Bight apex (NYBA) have been increasing over the last decade, providing an opportunity to study this phenomenon in an urban habitat. Whales in this area overlap with human activities, including busy shipping traffic leading into the Port of New York and New Jersey. The fidelity, population composition and demograpis of individual whales were analysed to better inform management in this high-risk area. Whale watching and other opportunistic data collections were used to identify 101 individual humpbackwhales in the NYBA from spring through autumn, 2012-2018. Although mean occurence was low (2.5 days), mean occupancy was 37.6 days, and 31.3% of whales returned from one year to the next. Individuals compared with other regional and ocean-basin-wide photo-identification catalogues (N=52) were primarily resighted at other sites along the US East Coast, including the Gulf of Maine feeding ground. Sightings of mother-calf pairs were rare in the NYBA, suggesting that maternally directed fidelity may not be responsible for the presence of young whales in this area. Other factors including shifts in prey species distribution or changes in population strucutre more broadly should be investigated.

KEY WORDS: Humpback whales · Megaptera novaeangliae · Mid-Atlantic United States · New York Bight · North Atlantic · Occupancy · Occurence · Photographic matching · Population strucute · Urban ecology.

Brown DM et al (2022). Site fidelity, population identity and demographic characteristics of humpback whales in the New York Bight apex. Journal of the Marine Biological Association of the United Kingdom 19.

Brown DM et al (2022). Site fidelity, population identity and demographic characteristics of humpback whales in the New York Bight apex. Journal of the Marine Biological Association of the United Kingdom 1-9.

 

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