Skokomish Tribe Monitors Harmful Algal Blooms in Hood Canal

The Skokomish Tribe is measuring the amount of toxins in harmful algal blooms in Hood Canal as part of an early warning system for shellfish poisoning.

While the state Department of Health and National Oceanic and Atmospheric Administration’s SoundToxins program monitors shellfish and algae regularly for toxin levels, the tribe is adding another level of precaution.

“The concept is to quantify the toxins in the water and algae before they get into shellfish tissues so we can share that information with the researchers at DOH and SoundToxins and say, ‘Hey, look for this in your samples,’” said Seth Book, the tribe’s environmental biologist.

Toxins associated with algal blooms can cause sickness and even death when contaminated shellfish are eaten.

During the first year of the tribe’s harmful algal bloom monitoring program, water and phytoplankton samples were taken weekly from 13 locations between the Hood Canal Bridge and Belfair, from May to September. Bloom events and associated toxins in Hood Canal were identified and categorized.

The tribe hired Dr. Sang Seon Yun to use the tribe’s newly developed water quality lab to analyze the samples on site instead of sending them away for testing.

The biggest success so far has been seeing the tribe’s testing methods work, since they were able to find toxin quantities as low as parts per billion, Book said.

“Although the levels we found were extremely low, shellfish concentrate these toxins in their flesh,” he said.

If a bloom occurs in Hood Canal during the winter months, the tribe’s lab will be able to analyze samples associated with those events immediately, said Ron Figlar-Barnes, the tribe’s lab manager.

The tribe looks for eight main toxins, including domoic acid, which causes amnesic shellfish poisoning and can result in permanent loss of short-term memory, or even death in severe cases. Other algal toxins of interest to the researchers are associated with diarrhetic and paralytic shellfish poisoning.

These toxins are often associated with the term “red tide,” which occurs when certain phytoplankton species with reddish pigments bloom, resulting in water that appears red.

“Not all harmful algae are colored red though and not every algae bloom is harmful, but it is still a mystery what triggers algae to produce the neurotoxin,” Figlar-Barnes said. “When the toxin occurs, the poisonings can affect sea animals, birds and humans.”

Skokomish Tribe intern Aaron Bentson-Royal takes water samples from Hood Canal this summer as part of the tribe’s harmful algal bloom monitoring program. Photo: Tiffany Royal