Seals Are Helping Scientists Map the Future of Antarctic Krill
To find out, researchers tracked the movements of krill-eating crabeater seals in the western Antarctic Peninsula (WAP) to build a model of the future distribution of krill, an important food source for Antarctic animals like penguins and whales. The results, published in Nature Climate Change Monday, showed that krill populations would shrink, shift offshore from northern coastal waters and move towards the south of the WAP, with major implications for the animals that feed on them.
“It will be challenging for a lot of species,” first author Luis Huckstadt of the Institute of Marine Sciences (IMS) at UC Santa Cruz said in a university press release. “Things are changing so fast in Antarctica, the changes we’re seeing in our model might be coming sooner than we expected.”
The reason the change in krill location is such a big deal is that it will force animals to travel further from shore for food.
“The shift in krill habitat away from coastal waters in the north has big implications for species like penguins and fur seals, which can’t make long foraging trips because they have to come back to land to feed their offspring,” Huckstadt said.
In addition, the decline in krill near the northern coast is projected to occur mostly during summer, when animals like humpback and minke whales migrate south in search of food. The southern shift of the krill could force them to travel even further in pursuit.
The researchers were able to use crabeater seal movements to make these predictions because the seals feed “almost exclusively” on krill, the study explained. They also travel near the surface of the water and only dive when they locate krill, which means by tagging the seals it is easy to get a picture of where krill are located, according to the press release. Using data from tracked seals, the researchers were able to build a model of krill distribution in the WAP and then see what happened to the model under changing conditions driven by the climate crisis. The scientists used data from 42 tracked seals collected in 2001, 2002 and 2007, Earther reported.
It is unclear how the predicted changes would impact crabeater seals themselves. The seals live in Antarctica year-round and don’t live in colonies, so it is easier for them to travel further for prey, the press release said. There is also a chance they may find new food sources, according to Earther, but scientists don’t know if they could do so fast enough.
The WAP is rapidly changing. In February, it recorded Antarctica’s highest ever temperature. Its sea ice is shrinking and multiple ice shelves have collapsed, Earther pointed out.
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