The California Department of Public Health has released an urgent statement warning against the consumption of Dungeness and rock crabs caught along the California coast until further notice, due to potentially lethal levels of domoic acid, which can cause amnesic shellfish poisoning, in both varieties.
The warning was released just days before the start of recreational Dungeness crabbing season in California, which was slated to begin on Saturday. The season has been postponed indefinitely, and rock crab farms, usually open all year, have been closed until further notice.
Many boat owners believe the problem is linked to warmer water temperatures in the Pacific this summer, reports The San Francisco Chronicle. Temperatures were measured at an average of over 60 degrees along the coastline, a full 6 degrees warmer than usual. These warmer temperatures are due to the “warm blob phenomenon," first observed in 2013 in the Pacific Northwest, a recent problem linked to climate change that's also responsible for the California drought this year. Recent warm ocean temperatures can also be attributed to the arrival of El Niño.
While warm temperatures are likely a contributing factor to the outbreak, as of this writing, officials do not know what caused the uptick in domoic acid in these crabs, nor do they know when it will subside. Troubling levels of domoic acid were noticed by researchers as early as May of this year. The California Department of Public Health has reported they will maintain the warning until domoic acid levels return to normal.
Domoic acid is a toxin that's produced by a type of microscopic algae known as pseudo-nitzchia and accumulates in the bodies of shellfish and fish. It's only once the toxin reaches a certain level that the fish can become harmful to predators, including human consumers.
Symptoms of mild domoic acid poisoning include vomiting, diarrhea, abdominal cramps, dizziness, and headaches; moderate domoic poisoning has resulted in confusion, seizures, trouble breathing, and permanent short-term memory loss, known as amnesic shellfish poisoning, in some patients. Severe domoic acid poisoning can be lethal. Symptoms can appear anywhere between 30 minutes to 24 hours after consumption of the seafood. As of Thursday, no consumption-related illnesses have been reported.
Dungeness crabbing season in California has brought crabbers from as far as Alaska to the Bay Area. Crabbers typically earn half their annual income during this period, and local chefs tend to serve between 40 and 60 Dungeness crabs a day in season.
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Dungeness crab image via Shutterstock