As domoic acid kills wildlife, officials issue shellfish alerts, quarantine for humans

As untold numbers of sea mammals and birds suffer and die from exposure to toxic algal blooms along California coastlines, including Orange County, state officials urge residents to exercise caution with their shellfish consumption.

Each year, California’s Department of Public Health, in conjunction with the Department of Fish and Wildlife, implements an annual quarantine on recreationally harvested mussels, due to the rise of potentially harmful levels of biotoxins during warmer months.

Commercially available shellfish from state-certified harvesters or dealers is not impacted by the quarantine, health officials assured in an April 24 release.

Extending from May 1 through Oct. 31, the sports harvested shellfish ban aims to stave off human cases of paralytic shellfish poisoning PSP, a condition that causes a loss of control in the arms and legs that can spread to the chest and abdomen, potentially causing fatal respiratory dysfunction.

Mollusks and crustaceans are known to absorb and store toxic microscopic algae in their digestive systems. Mammals who rely on such species to exist similarly ingest the toxins and, because cooking does not neutralize the poison, humans who ingest affected shellfish may also become sick.

While PSP is rare, about 582 people have had the foodborne illness since 1903, so far 39 deaths from poisoning have been recorded.

This year’s mussel quarantine arrives as another, wider public warning applies to sport-harvested bivalves, such as clams, scallops and oysters from Santa Barbara and Ventura counties southward to Los Angeles, Orange and San Diego counties.

Consumption of those species, along with mussels, could cause domoic acid poisoning, also called amnesic shellfish poisoning, which can take effect from 30 minutes to 24 hours after the eating of toxic seafood.

People show up with buckets to harvest marine creatures at White Point on Tuesday, July 7, 2020 in San Pedro. State health and wildlife officials Thursday announced a quarantine on recreationally harvested mussels on top of a similar bivalve shellfish warning issued last month.

(Myung J. Chun / Los Angeles Times)

Mild symptoms range from vomiting and diarrhea to abdominal cramps, headache and dizziness, while more seriously impacted victims may experience labored breathing, confusion, cardiovascular instability, seizures, short-term memory loss, coma or death.

Orange County has recently become one epicenter along California’s coastline for the discovery of ill, injured and stranded marine mammals and seabirds who are thought to have consumed toxic fish and shellfish.

A dead gray whale that washed up on Huntington Beach’s shoreline last month and a minke whale discovered in Long Beach’s Rainbow Harbor a week earlier, were found with toxic levels of domoic acid in their systems, ABC7 reported last week.

Huntington Beach’s nonprofit Wetlands and Wildlife Care Center Monday reported volunteers were treating 75 brown pelicans for domoic acid toxicity.

Residents seeking to access up-to-date information on shellfish advisories and quarantines can call the California Department of Health’s Shellfish Information Line at (800) 553-4133 or visit the agency’s Marine Biotoxin Monitoring website.