January 24, 2022 1:19 pm

The climate crisis will not affect all Antarctic seals equally

In one of the most remote oceanic areas in the world, the Weddell Sea, several species of seals breed and feed: among them the crabeater seals (Lobodon carcinophagus) and those of Weddell (Leptonychotes weddellii). For several years, thanks to the help of thousands of citizens, a team of scientists, led by the University of Canterbury in New Zealand, tracked satellite images in search of these mammals in the Antarctic Ocean.

The findings shed light on how these marine predators respond differently to climate change based on their unique ecologies.

One of the objectives was to create techniques for monitoring marine areas for the conservation of seals and other types of fauna. “We found that Weddell seals and crabeater seals breed near the places where they can find food,” he says. Mia ways, now Professor of Zoology at the University of Pretoria (South Africa) and working at the New Zealand University.

In a new study, published in the journal Global Change Biology, the researchers reveal how climate change will affect these breeding grounds. In fact, it won’t do the same. “Due to the climate crisis, crabeater seals will find it increasingly difficult to find a place to rest and raise their young, as well as having less food available,” says lead author Wege.

But the most surprising thing is that Weddell seals, instead, they will be minimally affected in the near future, “contrary to what happens in other places in Antarctica,” adds the expert.

The findings shed light on how these marine predators They respond differently to climate change based on their unique ecologies. “Most importantly, the study shows once again how these species can provide information about the entire ecosystem, and how valuable they are as sentinel species, especially when we think about ways to monitor the effectiveness of marine protected areas,” emphasizes the researcher.

Crabeater seal on the ice near the Weddell Sea. / Ursula Rack

Some more specialized and others more flexible

The specialized nature of crabeater sealsPreferring to breed on short-lived, unstable ice that drifts out to sea, they are more vulnerable to general increases in temperatures. If these ice shelves in the middle of the water melt, this species will have less space to breed.

In addition, they are very demanding in terms of their feeding. Most of your diet (> 90%) consists of krill antártico and they hardly change prey since they have become highly specialized predators with sieve-shaped teeth that are adapted to hunting krill. If climate change affects their prey in the ocean, these animals are more likely to suffer.

Current research shows crabeater seals are already at risk of losing their breeding and foraging habitat

Although the Weddell Sea is not as affected by climate change as the Antarctic Peninsula, current research shows that crabeater seals are already at risk of losing their breeding and foraging habitat even in this relative ‘refuge’.

In the case of weddell seals, which breed in fast ice, that is, the one that forms on the Antarctic continent, they remain on more stable platforms. In addition, they are more flexible in their diet, combining fish, krill and squid, and they move based on their prey.

“If we want to mitigate the decline in the ice-loving seal population as the climate warms, we must work now to create marine protected areas that ensure the longevity of these species and their ecosystems,” concludes Michelle LaRue, lead researcher on the study. from the University of Canterbury in New Zealand.

In October the annual meeting of the Commission for the Conservation of Antarctic Marine Living Resources, where world leaders will study the possibility of protecting more than 2.2 million km2 in the Weddell Sea, and according to experts, the differences between species will have to be taken into account to better plan their protection.

Rights: Creative Commons.


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