Some seals will struggle more than others to survive climate change

Climate change could have a significantly different impact on two species of seals in Antarctica, the crabeater and the Weddell seals, according to a new study published in the journal Global Change Biology.

The researchers, based at the University of Canterbury, New Zealand, studied and compared large populations of crabeater and Weddell seals using satellite images. “We found that Weddell and crabeater seals breed close to where they can find food,” said study lead author Dr. Mia Wege, a lecturer in Zoology at the University of Pretoria, South Africa.

However, there are significant differences in these two species’ feeding and breeding patterns. Crabeater seals are picky eaters, with the majority of their diet consisting of Antarctic krill, and they prefer to breed on short-lived, unstable ice-floes drifting on the ocean. By contrast, Weddell seals have a more flexible diet, including fish, squid, and krill, and they breed on ice that is fastened to the shore. 

“Because of climate change, crabeater seals will be increasingly challenged to find a place to rest and raise their young, in addition to having less food available to them. Very surprising of these results are that in the Weddell Sea, Weddell seals, on the other hand, are expected to be minimally affected in the near future, which is the opposite from what is happening elsewhere around Antarctica,” said Dr. Wege.

Having such a flexible and rich diet, and preferring to breed on more stable ground, the Weddell seals have a greater chances to adapt to climate change than the crabeater seals. The latter, being highly specialized predators that prefer to breed on ice-floes which are increasingly endangered by global warming, might have significant problems to survive in the near future.  “Our takeaway message here is that if we want to mitigate population declines for ice-loving seals as the climate continues to warm, we need to be working now to set aside marine protected areas to ensure longevity of these species and their ecosystems,” concluded principal investigator Dr. Michelle LaRue.

—

By Andrei Ionescu, Earth.com Staff Writer