Monday December 16, 2024
PhysOrg —
Murres, a common seabird, look a little like flying penguins. These stout, tuxedo-styled birds dive and swim in the ocean to eat small fish and then fly back to islands or coastal cliffs where they nest in large colonies. But their hardy physiques disguise how vulnerable these birds are to changing ocean conditions.
A University of Washington citizen science program—which trains coastal residents to search local beaches and document dead birds—has contributed to a new study, led by federal scientists, documenting the devastating effect of warming waters on common murres in Alaska.
In 2020, participants of the UW-led Coastal Observation and Seabird Survey Team, or COASST, and other observers first identified the massive mortality event affecting common murres along the West Coast and Alaska. That study documented 62,000 carcasses, mostly in Alaska, in one year. In some places, beachings were more than 1,000 times normal rates. But the 2020 study did not estimate the total size of the die-off after the 2014–16 marine heat wave known as “the blob.”
In this new paper, published Dec. 12 in Science, a team led by the U.S. Fish and Wildlife Service analyzed years of colony-based surveys to estimate total mortality and later impacts. The analysis of 13 colonies surveyed between 2008 and 2022 finds that colony size in the Gulf of Alaska, east of the Alaska Peninsula, dropped by half after the marine heat wave. In colonies along the eastern Bering Sea, west of the peninsula, the decline was even steeper, at 75% loss.