Bowhead Whales Are Adapting to Warming Arctic
So far at least, bowhead whales off Alaska may be benefiting from a warmer Arctic. Continue reading →
Few if any parts of the world are experiencing the impacts of climate change to the extent of the Arctic. But teasing out the precise effects of that change on the region's wildlife isn't always straightforward.
For some species, notably polar bears, the basic math isn't difficult: Polar bears need sea ice, and as that sea ice declines so most likely will they. Although even here, there is nuance: whereas populations in the southern Beaufort Sea and western Hudson Bay have experienced declines in numbers and body conditions there is some evidence that bears in the Chukchi Sea region are faring comparatively well. For other species, the picture is murkier.
In a landmark 2008 overview of the likely impacts of climate change on Arctic marine mammals, Sue Moore and Henry Huntington classified resident Arctic species into two groups: ice-obligate and ice-associated. The four species in the former group - polar bears, walruses, ringed seals and bearded seals - could be expected to be most clearly and directly affected by ice declines.
But among the responses of ice-associated species, they wrote, "there will likely be surprises." For example, for bowhead whales - which are found only in Arctic seas - "reductions in sea ice may actually enhance feeding opportunities."
Eight years on, there's some evidence this prediction is proving accurate, as Matthew Berger notes in a blog post for Nautilus. Berger quotes Moore, a NOAA biologist, as saying that, "At least for now, it's a very good time to be a bowhead whale. In terms of resiliency, bowheads could be near the top because they're already built to survive in tough conditions."
Moore cites as supporting evidence a 2015 study that found the body condition of bowheads hunted by Alaskan Eskimos to actually be improving, and Berger notes separate research that suggests habitats will "generally become more suitable for bowheads both earlier and later in the year in the Beaufort Sea, due to increases in the availability of krill and copepods, a group of microscopic crustacean."
Here, too, however, there are caveats, in that what may be true for bowheads in the Beaufort Sea region may not hold for those off northeastern Canada and western Greenland. There, warming waters may see an increase in Atlantic copepods at the expense of the larger and thus more calorie-rich Arctic ones - although it's possible that a greater abundance overall will counteract any declines in food quality.
As Berger observes: "There are a lot of unknowns when an ice-adapted world suddenly loses its ice."
Bowhead whales may see more feeding opportunities in a warming Arctic.
The new IMAX 3-D film "Humpback Whales" follows the marine mammals during their 10,000-mile migration. The film opens nationwide on Friday, Feb. 13. Pictured: A whale and her calf show their flukes off the coast of Maui. Baby humpbacks emulate their mothers’ social behavior as they learn important survival skills.
A mother humpback whale and her calf. The baby may grow to a length of nearly 60 feet and weigh as much as 50 tons.
A humpback whale and calf surface off the coast of Maui.
Director Greg MacGillivray films humpbacks with an IMAX camera while on location in Maui, along with assistant cameraman Robert Walker (left) and marine biologist Jim Darling.
A group of humpback whales bubble-net feed off the coast of Alaska. This is the one of the most complex social behaviors of any marine mammal.
An adult humpback whale breaches off the coast of Maui. Males create a song that lasts as long as 20 minutes at time, sometimes for hours, and is believed to be used in mating.
Marine biologist Jim Darling observes a humpback whale from a research vessel off the coast of Maui.
A humpback whale surfaces off the coast of Tonga.
Two humpbacks swim gracefully together.
The whales, now considered endangered, where hunted nearly to extinction until a moratorium on humpback whaling in 1966.
A humpback whale breaches in Alaska’s Inside Passage.
Humpback whales typically travel in pods. An estimated 80,000 humpbacks live today in every ocean.