Migrating Blue Whales Rely on Memory More than Environmental Cues to Find Prey
Oregon State University – Blue whales reach their massive size by relying on their exceptional memories to find historically productive feeding sites rather than responding in real time to emerging prey patches, a new study concludes.
Researchers examining records of both whale migration and oceanic conditions in the California Current Ecosystem found that blue whales almost perfectly match the timing of their migration to the historical average timing of krill production, rather than matching the waves of krill availability in any given year.
The findings suggest that blue whales locate prey by relying on memory to return to stable, high-quality foraging sites, which historically have served them well but could make it difficult for the whales to adapt if novel ecosystem changes emerge as a result of climate change.
Results of the study are being published next week in Proceedings of the National Academy of Sciences.
The concept of tracking the timing of food availability along migration routes is not unusual for land animals, but it has been more difficult to identify in marine creatures, according to Briana Abrahms, a research ecologist with the NOAA Southwest Fisheries Science Center in Monterey, Calif., and lead author on the study.
“We know that many species that migrate on land, from caribou in the Arctic to wildebeests in the Serengeti, enhance their survival by carefully adjusting the pace and timing of their migrations to find food as it becomes seasonally available along the way, rather than just migrating to get from point A to point B,” Abrahms said.
Blue whales seem to embrace that same strategy, which is enhanced by their memory, she noted. “These long-lived, highly intelligent animals are making movement decisions based on their expectations of where and when food will be available during their migrations.”
“This novel study is particularly noteworthy in that if focuses on the phenology, or timing of migration in a large marine predator,” said Sue Moore, an affiliate professor at the University of Washington Center for Ecosystem Sentinels, who was not involved in the study.
The study also raises the question of what will happen to the population if changing climate conditions cause food availability to deviate strongly from the whales’ expectations.
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