Red tide toxins shut down crabbing on Pacific Ocean coast

A large ribbon of red tide algae stretching from California to Alaska is prematurely ending crabbing season in some parts of the Pacific Ocean coast of Washington. Marine area 7 north, which includes Point Roberts, Blaine and Birch Bay, is still expected to open for crabbing season on Thursday, August 13, according to the WDFW.

On August 4, the Washington Department of Fish and Wildlife (WDFW) barred crab fishing in the 45 miles of coastal waters between Point Chehalis west of Olympia to the Queets River. The shutdown is an expansion of a closure between Point Chehalis and the Columbia River that has been in effect since June.

Dan Ayres, WDFW’s coastal shellfish manager, said more than half of the state’s 157-mile long Pacific coast has been shut to crab fishing.

The shutdown was prompted by an increase in domoic acid levels. Domoic acid is a natural toxin that affects certain types of marine algae and can trigger what is known as amnesiac shellfish poisoning (ASP) in humans. Symptoms of ASP include vomiting, nausea, diarrhea and abdominal cramps. In more extreme cases, patients can experience headaches, dizziness, disorientation, short-term memory loss, coma or, in highly concentrated doses, death. Cooking or freezing does not affect the toxin.

The ribbon of red tide algae, which is 40 miles across and 650 feet deep in places, has been thriving in the unusually warm waters of the Pacific Ocean for the last several months. While red tides are common this time of year, researchers from the National Oceanic and Atmospheric Administration say this ribbon is much larger and has lingered much longer than usual, and it is taking a toll on fisheries up and down the west coast.

The algal blooms appear to be receding, but harmful toxins can persist in shellfish for months, particularly in razor clams, Ayres said. Since razor clams are a major food source for crab, it’s likely the effect of the biotoxin will linger.

“At this point, this is strictly a coastal issue,” Ayres said. “We’ve seen no evidence of poisoning in Puget Sound and we have no reason to think it’ll affect the area.”

However, the season is effectively closed for waters affected by the toxins.

“This closure likely marks the end of this year’s coastal commercial crab fishery, which was already set close in September,” Ayres said.

The WDFW has order all commercial crab gear removed from the waters between Port Chehalis and the Queets River by Monday, August 10.

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