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Toxins Found in Crabs Along Pacific Coast


Toxins found in crabs along the Pacific Coast have prompted health advisories.

Just prior to this Saturday’s California recreational crabbing season, the California Department of Public Health issued warnings of potentially deadly levels of domoic acid found in Dungeness crab and rock crab caught along the coastline between Oregon and the southern border of Santa Barbara County.

Toxin levels exceeded the state’s action level for the crabs’ body meat as well as the viscera, commonly referred to as “crab butter” or the guts of the crab. As a result, the state Office of Environmental Health Hazard Assessment is recommending the Dungeness season be delayed and the rock crab fishery be closed.

The 600-boat commercial crabbing season is scheduled to begin November 15.

The Fish and Game Commission will hold an emergency public meeting at 8 a.m. Thursday in Sacramento, to be live-streamed on Cal-Span.

The San Francisco Gate ran a report detailing the matter.

“Delaying or closing the season is disappointing,” said Craig Shuman, marine regional manager of the state Department of Fish and Wildlife, which sets the dates for the season. “But public health and safety is our top priority.”

The toxins cannot be removed by cooking, freezing or any other preparation. Health officials say symptoms of poisoning can appear within a half hour to a day after someone has eaten toxic seafood, although no illnesses have been reported.

crab legs

Domoic acid is a naturally occurring toxin related to a large bloom of a single-celled plant called pseudo-nitzschia that is being attributed to unusually high ocean temperatures off the Pacific Coast. While waters in the region are usually around 55 degrees, they are reaching upwards of 60 degrees or more. This year’s bloom of Pseudo-nitzschia grew into the most harmful algal bloom ever recorded on the West Coast, according to the National Oceanic and Atmospheric Administration.

Domoic acid poisoning in marine mammals was first reported in 1998. Scientists at NOAA linked the unusually warm ocean waters this year with the algae bloom. High domoic acid levels were reported as far north as Washington and as early as May, a first since reporting began.

The CDPH explains, “In mild cases, symptoms may include vomiting, diarrhea, abdominal cramps, headache and dizziness. These symptoms disappear within several days. In severe cases, the victim may experience trouble breathing, confusion, disorientation, cardiovascular instability, seizures, excessive bronchial secretions, permanent loss of short-term memory (a condition known as Amnesic Shellfish Poisoning), coma or death.”

Meanwhile, The Oregon Department of Agriculture announced an advisory for all recreational crab taken between Cape Arago, south of Coos Bay, and the California border. High levels of domoic acid have been found in the viscera, but it does not typically affect crab meat at these levels. The advisory also adds that commercial shellfish products remain safe for consumers.

Crab harvested recreationally from Cape Arago north to the Columbia River do not fall under this advisory, although it is recommended that crab always be eviscerated prior to eating them. Evisceration includes removing and discarding of the internal organs and gills.

Kathi Lefebvre, a research biologist at the NOAA Northwest Fisheries Science Center in Seattle told The Oregonian, “The toxins are commonly present in the food web but this year, with this unprecedented bloom, they’re likely having a bigger impact than ever before. Our concern is that there does appear to be a link between warm water and bigger blooms, so what does this tell us about future years with warmer conditions?”


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Toxins Found in Crabs Along Pacific Coast