Alaskan whale deaths in 2015 could have been due to toxic algae

Current climate trends and increasing ocean surface temperatures are already expanding the northern geographic range of harmful algae blooms (HABs) in the Pacific Ocean. The world witnessed this in 2015 with the mass of warm water known as “the blob” that sat in the northern Pacific Ocean at that time.

In August of 2015, Digital Journal reported on the whale die-offs in Alaska, described by NOAA as an “unusual mortality event.” The deaths of the 11 fin whales,14 humpbacks, one gray whale, and four unidentified whales triggered investigations in the U.S. and in British Columbia.

The west coast toxic algae blooms started in May, 2015, and have been linked to die-offs of birds and mammals,including crabs and seals.

UC Santa Cruz

From August 2015 up through today, hundreds if not thousands of sea creatures, mammals, birds, walruses, and seals have died, usually from the effects of toxic algae blooms. Shellfish seasons have been put on hold because of increased levels of domoic acid and saxitoxin, both of them very common and potentially lethal algae-producing toxins.

Around the same time as the Alaskan whale die-offs, a similar event took place on the coast of British Columbia, Canada. Digital Journal reported on an investigation into the Canadian whale deaths done by scientists at the University of British Columbia.

Researchers at UBC were lucky to have intact whale carcasses to work with and did find toxic algae in the marine mammals. But CTV News Canada is reporting that NOAA researchers could not perform the tests needed on the Alaskan whale carcasses because they were too decomposed.

Toxic algae blooms can wreck havoc on the environment.
Photo by: Dr. Jennifer L. Graham USGS

USGS

NOAA fisheries veterinarian Kate Savage said it was possible the whales found off the coast of Alaska could have died because of toxic algae poisoning, but other factors could not be ruled out, like predation, vessel strikes or infectious disease.

Dr. Andrew Trites, director of the UBC Marine Mammal Research Unit says the domoic acid, found in these toxic algae blooms is a neurotoxin and is likely passed on to krill, a common food source for both fin whales, humpbacks and other whales. When ingested in large amounts, the neurotoxin can cause brain damage or even death in birds and mammals.