A new DOC report predicts that climate change could have a major impact on some of New Zealand’s marine mammals.
Co-authored by Jim Roberts, Anemone Consultants, and Hannah Hendriks, DOC’s Marine Technical Advisor, the research paper examines climate change in relation to marine mammals’ habitat, distribution, food sources and predators.
It looked at how specific climate change hazards, such as increasing sea temperatures, rising sea levels, changes in ocean circulation and effects on prey species, would impact marine mammals around New Zealand.
The report identifies changes in food supply as the biggest threat to marine mammals in New Zealand waters.
“This is likely to impact populations including kekeno/New Zealand fur seal in the Westland region and blue whales foraging at the South Taranaki Bight,” says Hannah Hendriks.
“Māui dolphins also appear vulnerable, based on their location at the warm end of the species’ range and an apparent low availability of prey species.”
Projected changes to the New Zealand environment include sea surface temperatures rising more than 3oC, changes in atmospheric climate and oceanographic circulation, rising sea levels, and widespread ocean acidification.
“As a result, it is possible species normally living in warmer subtropical waters like the dense-beaked whale, dwarf sperm whale, pan-tropical spotted dolphin, short-finned pilot whale and pygmy killer whale, will become more common around New Zealand, and potentially outcompeting some of the marine mammals we currently see,” says Hannah.
“Similarly, species that live in cooler subantarctic waters could become sparser around New Zealand as they move south.”
This review shows changes to the environment won’t be felt equally in all parts of New Zealand.
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Department of Conservation: The Papa Atawbai, 16 September 2022. Press release.
