It's a Bay Area tradition to find Dungeness crab starting to appear on local menus this month, and on Thanksgiving tables in a few weeks, but the crabbing season may not start on time this week depending on test results from the California Department of Public Health. As the Chron and CBS 5 are reporting, they're testing crabs from crab beds near eight different local ports — Crescent City, Trinidad, Eureka, Fort Bragg, Bodega Bay, San Francisco/Half Moon Bay, Monterey Bay, and Morro Bay — for the presence of domoic acid, a dangerous neurotoxin that comes from red algae which has been blooming along the warmer-than-usual Pacific coast this year.

It is, in fact, the biggest algae bloom of its kind ever observed, and this has already affected crab fishing on the Washington coast, where Dungeness crab season starts in the summer.

California Fish and Wildlife Department spokeswoman Jordan Traverso told the Santa Rosa Press-Democrat Friday, "everything kind of is up in the air right now" as test results won't come in until later this week.

The big trouble with domoic acid is that it survives cooking at high temperatures, and it can be very harmful, and even fatal, in humans. The algae can accumulate in fish and rise up the food chain, and because of the current algal bloom, there are a bunch of local fish that are on a current no-eat list, including Monterey Bay sardines, and any recreationally harvested mussels, clams, or whole scallops from anywhere along the Central Coast.

Worse than crabs, even, when it comes to potential health risks from the algae are bivalves like clams and mussels, and small fish like anchoves, because the toxin accumulates in their digestive tract and they are typically consumed whole, without being gutted.

Per the Press Democrat:

Symptoms of mild [domoic acid] poisoning include vomiting, nausea, diarrhea, abdominal cramps, headache, dizziness and confusion beginning 30 minutes to 24 hours after consuming toxic seafood.

Severe cases may cause difficulty breathing, seizure, coma and even death. Survivors in some cases may experience permanent short-term memory loss.

For the seafood-anxious, this is likely to mean that these fish and shellfish are going to be on a no-eat list for the foreseeable future.

Recreational Dungeness crab season would begin, if it's not delayed, on November 7, while the commercial season will begin later this month on different parts of the coast.

Earlier Dungeness crab season coverage on SFist.