Experts pretty much agree with the overall message of a recent warning from the state Department of Health and Social Services: Don’t eat personally harvested shellfish, ever.
The science methods cited by the state, however, have raised the eyebrows of a couple of aquaculture researchers. They say high toxin levels in algae blooms don’t necessarily mean poisonous shellfish.
Ray RaLonde, aquaculture specialist for the University of Alaska Sea Grant marine advisory program, has studied PSP in shellfish since 1995. He said toxicity of algae in the ocean is variable; the cells can disperse or concentrate, depending on the current.
“Cells and cell appearances and cell numbers gives you an indication that there could be a problem, but it doesn’t necessarily mean that there is,” he said. “The only confirmational testing that will actually tell you that you have a problem is testing for the toxin in the shellfish.”
RaLonde said the state did not test shellfish for toxins, and relied on algae testing alone to issue a recent warning. He said algae testing is useful, but only to identify areas where shellfish testing might be warranted.
He had other concerns about reports he heard based on the state’s announcement, such as where to find safe shellfish.
“One of the statements was that the only place to get shellfish, or safe shellfish, was from the grocery store,” he said. “Well, our oyster farmers don’t sell to just grocery stores.”
RaLonde said shellfish farmers in Alaska sell in many places, and their product is tested.
Despite questioning the state’s methods, RaLonde said its conclusions and warning are correct.
“The general statement by the part of everyone that’s engaged in this PSP debate is that you don’t eat untested shellfish, period,” he said. “People need to be warned: This is a bad time of year to be out there harvesting shellfish.”
He said that a beach with safe shellfish one day can have toxic shellfish the next, because the next high tide might carry an algae bloom. He said there’s no way to know whether shellfish is toxic without testing, and there are no tests available for personally harvested shellfish.
Gary Freitag, a professor and marine advisory agent for the Ketchikan area with UA Fairbanks, questioned assertions that PSP levels are higher than normal or the result of climate change. He said there’s no historical information to compare with data from the last few years.
Freitag said the state’s warning could be misconstrued, leading people to believe that “unusually” high levels now means it will be safe to harvest shellfish at another time of the year. He said people should eat only commercially harvested shellfish, no matter the month or the weather.
“It doesn’t matter what plankton concentrations are telling me. It’s just dangerous to eat shellfish from this area because we just simply don’t know,” he said. “We had, in November, high levels of PSP last year in animals that were tested, and so I mean there’s no predictive capability at this point to know what is safe to eat from a shellfish sampling.”
Freitag said the state’s warning also might lead some people to stop eating shellfish completely, or extend the concern to all seafood. He said that last year, after a similar warning from the state, some people decided to stop eating salmon, which can’t contain the toxin that leads to paralytic shellfish poisoning.
“It doesn’t matter because when people hear the ocean’s toxic, with high levels, they immediately assume that everything is vulnerable,” he said. “That’s the danger. We’re hurting our fisheries and things like that by making statements that are real inflammatory: that there’s high levels out there.”
Eric Wyatt is an oyster farmer, operating since 2004 on the outside of Prince of Wales Island, near Marble Island. He said commercial shellfish farmers and harvesters deal with the specter and the reality of PSP on a daily basis. Wyatt said there are stringent regulations and tests they must follow to make sure their product is safe.
Wyatt said his farm’s location is good, so his oysters rarely show any detectable traces of PSP. He said the state’s research into algae blooms is a new method of studying the issue, and he’s worked with researchers. But he also questioned how the data was released.
“Even though there’s more information being gathered about harmful algae blooms, we still don’t know the direct correlation to how that makes our shellfish not edible or edible,” he said.
Wyatt said that warnings about algae blooms could affect his business.
“People are concerned and they don’t understand,” he said. “They think they’re being ultra-safe, so there is a negative impact. But, on the other hand, we’re producing arguably the best shellfish in the world and it’s still limited in quantity, so we’re not having troubles in sales at this point.”
Wyatt said he understands the point of the state warning, and he agrees that people should avoid the potential danger of personally harvested shellfish.
“I want to assure people that product that is purchased from professional growers or harvesters is certified safe, and they should feel confident with that,” he said.
The state Department of Health and Social Services issued its warning on June 22nd. The warning stated that large blooms of algea that lead to PSP and DSP – which produces diarrhea – were found in Southeast Alaska.
The warning stated that all locally harvested shellfish can contain toxins, including clams, mussels, oysters, geoducks and scallops. Crab guts, but not the meat, also can contain PSP.
The state warning stressed that commercial shellfish is considered safe.