Big changes from warming climate boost risk of toxic algae blooms off Alaska coasts, report says

Record-low levels of sea ice and higher risk of harmful algae blooms that can poison people and animals are among the “profound” changes taking place in Alaska as the climate warms, according to the annual Arctic Report Card released by the National Oceanographic and Atmospheric Administration on Tuesday.

“One of the more remarkable features of Arctic sea ice in 2018 was the dearth of ice in the Bering Sea, which was at a record low extent for virtually the entire 2017/18 ice season,” the report said.

The warming conditions have led to a tremendous increase in productivity levels in some parts of the Bering, the report said. A downside is the expected expansion of harmful algae blooms, commonly called “red tides," including those that cause paralytic shellfish poisoning after toxins enter the food chain, the report said.

“It appears these blooms are going to be able to go into new areas because of the changing environment,” said Kathi Lefebvre, a research biologist with NOAA and contributor to a section of the Arctic Report Card. “That’s a risk, because if they go into areas they have not been before, people may not be prepared for that.”

High concentrations of algal toxins have been found in Arctic clams, seals, walrus, and whales, animals harvested for subsistence in the Arctic, the report said.

Reports of sickness and deaths from PSP in Alaska date back decades, but they’ve been primarily limited to southern coastal waters, such as Southeast Alaska and the Aleutian Islands.

“We are seeing more harmful algae blooms, and we are seeing them propagate to the north,” said Bruce Wright, senior scientist with the Aleutian Pribilof Islands Association who has studied PSP in Alaska since 1978.


A “recent significant observation” are “extremely high numbers” of bloom-producing spores found in the Chukchi Sea sediment off northwest Alaska, the report said.

It’s “among the highest densities ever reported” for that particular species, the report said.

Wright said he believes a massive bloom in 2015 centered in the Gulf of Alaska caused paralytic shellfish poisoning in animals, severely disrupting the food chain and causing many thousands of murres to starve to death, after the small fish they eat had died from ingesting PSP.

[Hundreds of mysteriously stranded seabirds crowd Alaska rescue center.]

Samples of dead sand lance fish tested in 2015 showed incredibly high levels of PSP in their system, enough to kill birds, he said.

A new “blob” of warm water re-emerging in the Gulf of Alaska could lead to another dangerous algae bloom, he said.

“I’m worried,” he said.

Alex DeMarban

Alex DeMarban is a longtime Alaska journalist who covers business, the oil and gas industries and general assignments. Reach him at 907-257-4317 or