Concerns about shellfish safety, an age-old problem in Puget Sound and Hood Canal waters, are growing along with the microscopic algae that produce them. Summer closures for recreational shellfish are coming sooner, and in more areas.
As of June 19, for example, almost all Hood Canal recreational shellfish beaches are under some type of closure or advisory. The most recent closure came June 17 along the Jefferson County shore from the Hood Canal Bridge to Brown’s Point on the Toandos Peninsula. There are also recurring shellfish closure issues for Discovery Bay.
At a meeting earlier this month in Quilcene, members of the public asked a state Department of Health official what could be done to prevent or counter the issues leading to closure. The answer: nothing, because it is a naturally occurring problem.
NOTHING NEW
Biotoxin issues are not new.
A sailor named John Carter, 24, died at 1:30 p.m. on June 15, a victim of paralytic shellfish poisoning. At 8 a.m., Carter ate some roasted mussels as part of his breakfast, along with some of his work crew, their usual practice when finding shellfish on the beach.
Soon after they left the cove where they had breakfasted, several of the crew experienced numbness in their faces and extremities, quickly extending to their whole bodies, accompanied by sickness and giddiness, reported supervisor Robert Barrie.
Carter’s pulse gradually grew weaker until he died, when his lips turned black, his hands, face and neck considerably swollen. Three others who were stricken survived.
The cause of affliction was not in the number of mussels eaten, but in their location, said Barrie, who had eaten as many as any in the party and was not the least affected by them. Mussels gathered on the sand were lethal, but not those taken from the rocks, he reported.
This account, from English Capt. George Vancouver’s 1793 journal, could have happened today.
SHELLFISH TOXICITY
Levels of shellfish toxicity vary enormously from place to place, among species, and across time, both seasonally and through the centuries, for a variety of reasons.
Mussels, clams, oysters and other hinged shellfish are filter feeders, taking in nutrients from the water surrounding them and in the process, cleaning the water.
During this process, marine biotoxins produced by certain kinds of microscopic algae, naturally present in marine waters, are taken in by shellfish, which remain unaffected. Normally, the levels of biotoxin are too low to affect those who eat them, but when algae growth increases, so does the level of biotoxins taken in by shellfish.
The higher the concentration of biotoxins in shellfish, the larger the effect on humans and other mammals eating them. Death can come as quickly as 15 minutes after consumption.
Unfortunately, toxin levels are undetectable by taste or visual inspection, and cannot be neutralized by cooking or freezing. The same shellfish on a beach can be safe or not, depending on their food source, without any change in appearance or taste.
The toxin levels increase, as algae reproduce quickly in warm temperatures, sunlight and nutrient-rich waters, a state called a bloom. This has been called a red tide, but the toxin levels are not indicated by the color of the water: Clear water may be in a bloom, and murky water may be toxin-free. Studies have shown that biotoxins are not related to water pollution.
The Washington State Department of Health uses laboratory testing, and has been operating a testing program since 1957. The operation was scaled up in 1991 with the Sentinel Mussel Monitoring Program.
CAGED MUSSELS
Functioning much like canaries in coal mines, caged mussels are checked regularly at 72 sites, with frequency increasing when toxins are present. Different types of shellfish absorb, and eject, the toxin at different rates, and mussels are one of the quickest.
“They take it in quickly and they can flush it quickly,” said Clara Hard of Washington State Department of Health’s Office of Environmental Health and Safety, who spoke at a public meeting in Quilcene in early June.
Patterns of biotoxin presence can change quickly. “Toxins can be very spotty,” noted Hard. “It does seem earlier in the year and toxin levels are increasing. In 10 days, we saw razor clams go from nothing to three times our limit.”
Commercial shellfish are regularly tested to ensure purity, but recreational shellfishing occurs in broad areas.
“We don’t have the lab capacity to test for all beaches. I wish we could,” said Hard. “We use the data to close the smallest area possible.”
Sites must have two consecutive clear tests to be reopened.
There are three known types of biotoxins transmitted by eating shellfish.
PSP
Paralytic shellfish poisoning (PSP) affects the nervous system, causing a tingling of the lips and tongue that may progress to tingling of the fingers and toes, then loss of control of the arms and legs, and, finally, paralysis of the muscles of the chest and abdomen, causing death by respiratory arrest. Onset may be from five minutes to 10 hours after ingestion.
ASP/DSP
Amnesic shellfish poisoning (ASP) is a result of domoic acid biotoxin, which was first detected in Washington in 1991. It causes vomiting, nausea, diarrhea and abdominal cramps in the first 24 hours. Neurological symptoms of dizziness and confusion develop within 48 hours in more severe cases. Short-term memory loss can be permanent; death is the most extreme outcome.
There was a sharp increase in domoic acid this spring.
“It doubled in almost two days, which is very scary,” said Hard.
Prior to this year, the last closure in Jefferson County was in 2006.
Diarrhetic shellfish poisoning (DSP), caused by okadaic acid biotoxins, produces diarrhea, vomiting and intestinal discomfort, but is not lethal. Complete recovery in three to four days is the norm, but there is some concern that the toxins may promote tumors long-term.
There is no antidote for marine biotoxins. Patients simply have to wait for the toxins to naturally flush from their bodies. In severe cases, victims can be placed on life support until effects subside. The last death caused by toxic shellfish in Washington was contracted at Sekiu Point in 1942. However, there were nine confirmed illnesses in 2012.
In September 2012, a woman in Kingston, in nearby Kitsap County, experienced tingling shortly after eating some oysters. She called the friend who had supplied them to her; he advised her to go to the hospital. She called 911, was airlifted to Harborview Medical Center in Seattle, where she was on life support for two days. She emerged from her coma to recover, but had she been slower in reporting, she would have died, according to medical officials.
Recreational shellfishers are advised to check for shellfish safety on the intended harvest day, since conditions can change quickly. Check online at
doh.wa.gov/shellfishsafety.htm, call 800-562-5632 toll-free, or contact the local health department; for Jefferson County, call 385-9444.
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