VICTORIA -- A massive marine heatwave off the West Coast of Canada and the U.S. killed one million seabirds between 2014 and 2016, according to new study published Thursday.
Approximately 62,000 dead or dying common murres – a species of small Pacific seabird – washed ashore between California and Alaska from the summer of 2015 to the spring of 2016.
Over just two days in 2016, investigators say 6,540 dead murres were found on a beach near Whittier, Alaska, amounting to 8,000 bodies per mile of shoreline, according to the study.
Researchers with the U.S. Geological Survey say the birds were clearly starving, and their numbers represent just the tip of the iceberg.
"The unprecedented loss of about a million common murre seabirds in the Northeast Pacific during the severe and prolonged marine heatwave of 2014-16 raised a red-flag warning about the state of marine ecosystems on the continental shelf of western North America," the study's authors said in a statement Thursday.
The study, published in the science journal PLOS ONE, says a mass of warm water, which came to be known as "the Pacific Blob," killed off vital fish and plankton feedstocks and led to the largest toxic algae bloom in history.
"The murre die-off revealed the onset of a major disruption in the flow of energy through marine food-webs which led ultimately to alarming declines in reproductive output and population size of murres, other seabirds, commercial fish, and great whales during 2016-19."
Researcher John Piatt and his colleagues at the U.S. Geological Survey collected data on thousands of bird carcasses collected from West Coast beaches.
In Alaska, where many of the dead birds were found, researchers recorded sightings of dead murres at a rate 1,000 times higher than normal.
The study also found an unprecedented failure among murre breeding colonies to produce any young between 2015 and 2017.
"Researchers are only beginning to understand the mechanisms and full magnitude of effects of the 2014-16 heatwave, and what it portends if such heatwaves become stronger and more frequent, as predicted," the authors said.
