Will Climate Change Affect Arctic Whale Migration?

A study published by researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute and a team of scientists is evaluating the relationship between changing sea ice and beluga whale migration. They are also assessing the summer residency patterns of a number of populations over two decades of dramatic sea ice changes in the Pacific Arctic. Working in collaboration with Native hunters in Alaska and Canada, the researchers discovered that beluga whales showed an ability to deal with a changing environment.

In their research published in the Royal Society Biology Letters titled, "Genetic Profiling Links Changing Sea Ice to Shifting Beluga Whale Migration Patterns," scientists presented that beluga whales, popularly known as the white whale, (Delphinapterus leucas), showed a tremendous capacity to deal with greatly varying sea ice conditions from one year to the next over a 20-year time period as they return to their traditional summering grounds each year.

With the increasing concern over global warming, declines in the Arctic sea ice show the most dramatic proof of climate change on ocean systems. "It was not clear how sea ice influences beluga whale migration patterns and their summer habitat use, and climate change has added urgency to determining how environmental factors might shape the behavior and ecology of this species," said Greg O'Corry-Crowe, Ph.D., the lead author of the study and a research professor at FAU Harbor Branch Oceanographic Institute. His research focused on combining molecular genetic analysis with field ecology to study the molecular and behavioral ecology of marine apex predators.

O'Corry-Crowe and his collaborators utilized a combination of genetic profiling, sighting data, and satellite microwave imagery of sea ice in the Bering, Chukchi and Beaufort seas. This resulted in discovering dramatic shifts in migration behavior during the years with unusually low spring sea ice concentration. There was also an increase in killer whale (Orcinus orca) sightings that reportedly preyed on beluga whales.

Much of the data analyzed by O'Corry-Crowe and his collaborators were obtained using genetic fingerprinting to investigate the population of origin of whales returning to four traditional coastal sites in the Alaskan and Canadian Arctic between 1988 and 2007. They also gathered detailed beluga sightings and harvest data for the same period to assess inter-annual variation on the timing of return. Lastly, they evaluated sea ice data in the Bering, Chukchi and Beaufort seas to calculate seasonal and regional patterns of sea ice from 1979 to 2014. They also utilized data from tissue samples from 978 beluga whales that were gathered over a 30-year period.

"Continued reductions in sea ice may result in increased predation at key aggregation areas and shifts in beluga whale behavior with implications for population viability, ecosystem structure and the subsistence cultures that rely on them," concluded O'Corry-Crowe.