Whether shellfish harvested from rich clam beds from Ninilchik to Port Graham on Alaska’s Kenai Peninsula is safe from various toxins has never been extensively tested before this summer. But thanks to a three-year study and $120,000 awarded to the Kachemak Bay Research Reserve (KBRR), shellfish on all the main beaches were tested in July and August and will continue to be the next three years.
Terry Thompson, director of KBRR, said the project is significant because for the first time, the data will form a baseline study serving for years to come. So far, so good – tests for paralytic shellfish toxins showed no significant levels in shellfish tested for paralytic shellfish toxins.
“Last spring, the (Department of Environmental Conservation) put out a call for proposals looking for three coastal communities to do a baseline study of PSP in recreationally harvested shellfish, because these aren’t tested in Alaska for toxins,” Thompson said. “The DEC will always tell people ‘if you harvest shellfish, you do so at your own risk. To be safe, you need to buy them from a retail outlet that has their product tested.’ But thousands of people harvest shellfish in Alaska. The Legislature put some funds out to do (tests).”
Monthly monitoring in summer
Alaska Department of Environmental Conservation, Division of Environmental Health, solicited proposals from government organizations. KBRR was selected to conduct the program. Partners include the Ninilchik Traditional Council, Port Graham Village Council, Seldovia Village Tribe and NOAA’s Kasitsna Bay Lab and Department of Fish and Game in Homer – as well as local volunteer Nicki Szarzi and the Kachemak Bay Wilderness Lodge.
“They all go out once a month during the lowest tides from May to September to harvest shellfish,” Thompson said. They harvest razor clams, butter clams, little neck clams or mussels. So far, after a session in July and another in August, the news has been good.
Shellfish must have fewer than 80 micrograms of paralytic shellfish toxins to be considered safe for human consumption. Using what’s called the mouse bioassay test, PSP levels below 34 micrograms cannot be detected. Anything below 34 micrograms is undetectable, meaning the food is safe. Shellfish containing more than 80 micrograms of PSP are unsafe for humans.
“Another aspect that made this study exciting was the timing. I had received an email from Chief (Patrick) Norman out of Port Graham (Village Council). He said they hadn’t been harvesting clams. Now that they hadn’t harvested for many years, they were starting to see more clams, and wanted to start harvesting again as a subsistence foods. They were curious to see if there was potential problems with PSP,” Thompson said.
Chief Norman is one of the shellfish monitors. “We haven’t harvested them here for 25-30 years. On minus tides, we used to get cockles and butter clams. Then they suddenly they disappeared,” Norman said. “We haven’t figured out what happened. This testing will help in one question. We want to know if they are safe.”
Testing has limitations, and even a result clean of toxins doesn’t guarantee that entire beaches are clean. “That’s because the test is only as good as the tide we collect it on. If we do it on Saturday, it may be 10 days before we get results back,” Thompson said. “Each tide changes the dynamics of potential toxins in clams.”
Scientists know Kachemak Bay waters are safe when it comes to oyster harvests because oysters are always tested. “But we don’t know if the clams take on toxins the same way as an oyster,” he said.
It’s also important to become familiar with PSP levels in Kachemak Bay and along Cook Inlet, Thompson said, because there have been several deaths to PSP in the past on nearby Kodiak Island. Up to 20,000 micrograms of the toxin have been measured in shellfish there – far more than the 80 microgram level, the point where human consumption should be avoided.
“These were tested at very high levels,” Thompson said. “We’ve taken our assumptions based from oyster farmers, but we don’t know if they take on PSP at the same rate. We have very heavy use of our shellfish. A lot of the folks from Anchorage and the Mat Su come down, as well as people on the Peninsula, to harvest.” People may have gotten sick at times from Kenai Peninsula shellfish, but there have been no visible, dramatic outbreaks, Thompson said. “It’s a pilot project. As we learn more, we can modify what we are doing. One of the things of real interest, because there have been no tests of butter clams, is that they can hold their toxins for two years. By studying them, we can look into a window in the past.”
The previous report was first published by The Homer Tribune and is republished here with permission.