Vigilance advised after saxitoxin found in clams

December 6, 2019

Scientists have detected toxic algae in clams from the Bering Strait and Chukchi Sea regions of northern and western Alaska, according to a new bulletin.

It’s an indication that ocean warming is moving northward, allowing the growth of Alexandrium catenella, a type of algae that can produce saxitoxin. If ingested, saxitoxin targets the nervous system and blocks nerve function. It can cause potentially deadly paralytic shellfish poisoning, a risk to people harvesting and consuming shellfish in affected locations.

The new bulletin comes from a collaboration of the National Oceanic and Atmospheric Administration, North Slope Borough Wildlife Department, Alaska Sea Grant, Woods Hole Oceanographic Institution, Alaska HAB Network, and Alaska Ocean Observing System.

The affected clams were part of a larger sampling effort throughout the Chukchi Sea and the Bering Strait region. The clams were collected at two offshore locations 70 miles north of Saint Lawrence Island in the Bering Strait region, and 50 miles north of Cape Lisburne in the Chukchi Sea, and contained levels of saxitoxin over the regulatory limit.

Kathi Lefevbre with NOAA Fisheries analyzed the clams and deemed them unsafe for human consumption.

(This clam was among a sample taken from a site about 70 miles north of St. Lawrence Island.
Photo courtesy of NOAA Fisheries.)

These significant findings indicate that high levels of Alexandrium catenella can be present in shellfish far north into the Bering Strait region and Chukchi Sea. They reveal that paralytic shellfish poisoning should be a concern for people in western and northern Alaska who depend upon healthy ocean resources for their food security and culture.

Vigilance by residents of the affected regions is needed because no amount of cleaning, freezing or cooking can remove algal toxins. The bulletin is being provided to tribes and other residents throughout the Bering Strait region as well as healthcare providers, and lists people and agencies to contact for more information.

“Thanks to the teamwork and concern shown by NOAA Fisheries and Woods Hole Oceanographic Institution, the coastal communities of northern and western Alaska got this information first. The communities closest to these offshore results rely on the ocean for nutritional, cultural and economic well-being, “ said Gay Sheffield, Alaska Sea Grant’s Marine Advisory agent in Nome.

Download the bulletin from Alaska Sea Grant.