Sport crabbing returned Monday to Oregon's South Coast after the region's Dungeness received an all-clear grade for eating after yet another closure caused by domoic acid levels.
All six Dungeness pulled Feb. 27 off Brookings tested well below the alert level for the marine biotoxin, allowing state fishery and health officials to lift the regional closure enacted Feb. 16, according to the Oregon Department of Agriculture, which governs crustacean edibility in Oregon.
The crab made a quick turnaround from a similar sampling off Brookings on Feb. 13, when three of six Dungeness sampled sported domoic acid levels as high as 55 parts per million, according to Judy Dowell from the ODA's food-safety program in Salem.
The safety alert kicks in when any crab sampled in an ocean zone eclipses 30 parts per million of domoic acid, Dowell said. Since crab are so mobile, the ODA not only closes the zone where the offending crab was sampled but also adjacent zones, which stretched the closure to Cape Blanco, Dowell said.
Dowell said food-safety officials were not surprised by this week's test results, which represented the second straight week of passing domoic levels.
"Crab seem to get rid of the toxin pretty fast," Dowell said. "They're not like razor clams; they hold onto it for a long time."
Dungeness most commonly get domoic acid from eating infected razor clams.
The sport season had been open only 16 days before the latest domoic acid-related closure, records show. The recreational season was closed Oct. 22 from Cape Blanco south to the California border, and the commercial season here did not open until Feb. 4.
The commercial crabbing season has remained open but all harvested crab had to be eviscerated because that is where domoic acid accumulates in crab, according to the ODA.
That's why health officials recommend always eviscerating all crab before cooking. When whole crab are cooked in liquid, domoic acid may leach into the cooking liquid.
Domoic acid can cause minor to severe illness and even death in humans. Severe poisoning can result in dizziness, headaches, vomiting and diarrhea.
More severe cases can result in memory loss and death. Shellfish toxins are produced by algae, and are most readily absorbed by filter-feeders such as razor clams.
Dungeness is by far Oregon's most valuable commercial fishery. Last year's season opener was also delayed, but the 20.4 million pounds of Dungeness landed fetched a record $62.7 million for the fleet. Last year's landings were about 22 percent higher than the 10-year average, according to the Oregon Department of Fish and Wildlife.
— Reach Mail Tribune reporter Mark Freeman at 541-776-4470 or firstname.lastname@example.org. Follow him on Twitter at www.twitter.com/MTwriterFreeman.