North Coast residents hoping to kick off recreational Dungeness crab season this month will have to wait a little longer. On Nov. 5, the California Department of Fish and Wildlife announced that state health agencies recommended delaying the recreational Dungeness crab fishery after determining that elevated levels of domoic acid in local crab posed a risk to human health. The closure area now extends from Reading Rock south to Ten Mile, and recreational take and possession of Dungeness crab is prohibited within those waters.The closure will remain in place until OEHHA, in consultation with CDPH, determines that domoic acid “no longer poses a significant public health risk.”Domoic acid is a strong neurotoxin produced by Pseudo-nitzschia, a naturally occurring single-celled marine alga that can proliferate under certain ocean conditions. The toxin can accumulate in shellfish, other marine invertebrates, and some fish without causing illness in the animals themselves. In humans, low-level exposure can cause nausea, diarrhea, and dizziness, while higher exposures may lead to persistent short-term memory loss, seizures, and, in some cases, death.Jennifer Kalt, executive director of Humboldt Waterkeeper, said marine heat waves can contribute to the growth of algae that produce domoic acid.“The warm ocean waters are really what drives the domoic acid levels to toxic levels. My understanding is that there’s always some of the algae that produce domoic acid around, but their levels get exacerbated when there’s a marine heat wave,” said Kalt. “It’s kind of like the toxic algae in the rivers. They’re always around, but somehow, you know, when there are higher water temperatures, their populations explode, and then they are causing high levels of neurotoxins.”While the recreational fishery has been delayed due to domoic acid concerns, the commercial Dungeness crab season remains delayed due to whale entanglement concerns.State officials have not announced when recreational crabbing may resume. The fishery will remain closed until testing shows that domoic acid levels have decreased and no longer pose a significant public health risk.Even after the fishery reopens, Humboldt Waterkeeper encourages crabbers to remove the internal organs, often called “crab butter,” before cooking. The organization’s cleaning guidance notes that marine biotoxins such as domoic acid, as well as contaminants like dioxins, tend to accumulate in those tissues.State officials encourage anglers to monitor fishery updates and public health advisories before harvesting crab. Until health agencies determine that the health risk has passed, recreational Dungeness crabbing along the Humboldt County coast will remain closed.Read More
