Now a lecturer in Zoology at the University of Pretoria in South Africa, Dr Wege says the interesting part of their findings relates to how climate change will affect breeding locations differently.
鈥淏ecause of climate change, in addition to having less food, crabeater seals will be increasingly challenged to find a place to rest and raise their young. Surprisingly, Weddell seals are expected to be minimally affected, which is the opposite of what is happening elsewhere around Antarctica.鈥
The study鈥檚 goal was to use these two unique datasets, created in New Zealand by University of mini传媒 scientists, as part of a set of monitoring techniques for marine protected areas in the remote and mostly ice-covered Southern Ocean to conserve seals and other wildlife.
These findings provide 鈥渆vidence that different species will be exposed to impacts from climate change differently,鈥 says the principal investigator of the study, Dr LaRue from the University of mini传媒听School of Earth and Environment.
鈥淥ur takeaway message 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,鈥 Dr LaRue says.
Dr Wege says the findings shed light on how these marine predators respond differently to climate change based on their unique ecologies. 鈥淢ost importantly, our study again shows how these species can provide information about the entire ecosystem, and how valuable they are as sentinel species, especially when we are thinking of ways to monitor the effectiveness of marine protected areas. They certainly are more than just cute faces.鈥
Life on the Ice
The research team鈥檚 results point to the specialist nature of the crabeater seals making them more vulnerable to climate change impacts. Crabeater seals prefer to breed on the unstable and short-lived ice drifting on the sea, called pack-ice. They raise pups on these ice floes in the middle of the ocean 鈥 when pack-ice melts, that鈥檚 less space to raise their young. Weddell seals breed on fast-ice, which is ice fastened to the Antarctic continent 鈥 a more stable breeding platform.
Crabeater seals are picky eaters, most of their diet (>90%) consisting of Antarctic krill.听 If climate change affects the seals鈥 prey in the ocean, crabeater seals are more likely to suffer. Crabeater seals can鈥檛 switch to eating anything other than krill. Evolution has made them a specialised predator. Their teeth are shaped to be perfect sieves for krill. The unstable ice floes and specialised diet together are not good signs for the future of the species. Although the Weddell Sea is not as harshly affected by climate change as the Antarctic Peninsula, current research shows that even in this relative haven crabeater seals are already at risk of losing breeding and feeding habitat.
Weddell seals are more flexible in their diet, eating fish, krill, and squid. Their presence is mostly influenced by non-climate related factors such as distance to the continental shelf where prey tend to aggregate. The Weddell Sea may still have enough food resources to sustain the current populations of Weddell seals.
鈥淐learly, any planning to protect the Southern Ocean ecosystem should take into consideration these differences. There are no easy answers,鈥 says study collaborator听听from Point Blue Conservation Science, a non-profit organisation in California, United States, dedicated to developing climate-smart science for conservation.
Global leaders are considering听听in October at the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) annual meeting.
- The research article 鈥業ce matters: life-history strategies of two Antarctic seals dictate climate change eventualities in the Weddell Sea鈥 was published 7 September 2021 (Wed 8 Sep NZTime) in听Global Change Biology:听
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