Soon after Yurok Tribal member Josh Norris moved to Del Norte County eight years ago, he started sharing in a traditional Yurok practice, mussel gathering.
Every winter, Norris’s family and friends harvest dozens of mussels during minus tides, holding big mussel feeds and even canning mussels to eat the tasty shellfish throughout the year.
This winter was different.
In October, the California Department of Public Health issued a ban on collecting certain shellfish, including mussels, in Del Norte and Humboldt counties due to dangerously high levels of a biotoxin that accumulates in shellfish and can harm humans — even kill in some cases — known as Paralytic Shellfish Poisoning toxins.
The PSP toxin levels detected in mussels from Wilson Creek Beach last fall were the highest levels ever detected in Del Norte County, 75 times greater than the federal alert level and 16 times higher than the Del Norte County’s previous record.
On Friday, the state finally lifted the ban on gathering shellfish after mussels sampled from Del Norte and Humboldt coasts showed that PSP toxins had finally dropped below the level of concern.
That leaves only six weeks of harvesting before the annual shellfish quarantine kicks in from May 1 to Oct. 31, which is implemented statewide due to higher levels of the toxin found during the summer time.
“I’ve been talking about it with my family for weeks now,” Norris said. “It’s time to get down there. We’re really hungry for them.”
Norris appreciates the high nutritional value of mussels and low environmental impact of consuming a local resource that doesn’t require industrial agriculture or shipping costs.
Suzanne Fluharty, an environmental specialist for the Yurok Tribe Environmental Program, has collected mussels throughout the winter, sending them into the CDPH for testing. She also fielded inquiries from tribal members wanting to go harvest mussels.
“I’ve had numerous calls and a steady stream of tribal members concerned about it,” Fluharty said.
The monitoring of toxins, via mussel sampling like that done by Fluharty, is about the only thing that can be done to protect public health: The causes of high PSP toxin levels are varied and not fully understood.
Regardless of the causes, this winter exhibited an uncharacteristically high occurrence of PSP toxins. Just before the quarantine on shellfish harvesting was lifted in Del Norte and Humboldt counties, an out-of-season quarantine was implemented by CDPH for Marin County after high levels of PSP toxins were detected there.
Mussel harvesting in Southern Oregon was closed for five months longer than most years. The entire Oregon coast was closed to harvesting for three months longer than typical.
“Climate change, increased ocean eutrophication (high concentration of nutrients in water) and commercial shipping are believed to contribute to the increasing frequency and occurrence of these blooms worldwide,” according to a 2011 article published by the National Center for Biotechnology Information.
Kathleen Sloan, director of the Yurok Tribe Environmental Program, agreed.
“This trend is tied to climate change,” she wrote in an email to the Triplicate. “It is happening all over — and is tied to warming oceans as a result of a changing climate.”
Environmental scientists at CDPH are less willing to point to one factor, pointing to the possibility that an influx of phytoplankton of the genus Alexandrium (the genus that produces PSP toxins) may have been transported into the region and slowly traveled down the coast.
“The causes for the increase and persistence of the PSP toxins are not known and these events are therefore unpredictable. This illustrates the importance of frequent monitoring throughout the year, and the need to be aware of current conditions,” CDPH officials said in an email.
For Norris, his personal experience seems telling.
When he lived in Southern California, Norris was accustomed to seeing ‘red tides,’ an occurrence of visible-to-the-naked-eye algal blooms produced by a phytoplankton very similar to the kind that produces PSP toxins. Red tides can be an indicator of PSP toxins, CDPH officials said.
“I don’t remember ever seeing it up (in Del Norte) but this year I could actually see it with my eyes, and that was a shock to me. That was really disconcerting,” Norris said.
Due to the extreme symptoms that can result from PSP toxins, it is important to pay attention to quarantines before harvesting.
“Early symptoms following ingestion include tingling of the lips and tongue, which then progresses to the fingers and toes, followed by the loss of control of arms and legs. Difficulty in breathing ensues from paralysis of the muscles of the chest and abdomen, which results in death at high toxin doses,” according to the NCBI article.
The CDPH Biotoxin Information Line (1-800-553-4133) provides updates on current quarantines and health advisories throughout the year.
For more information about PSP toxins, red tides and monitoring, read the Triplicate report “Mussels tested for toxins: quarantine prolonged” published Dec. 21, 2012, at Triplicate.com.
The published edition of this article inaccurately stated that PSP toxins detected from Wilson Creek Beach were the highest levels ever detected in all of California. Last fall's results from Wilson Creek were the highest ever detected in Del Norte County.