A couple of Old Harbor students recently won recognition for their scientific experiments, one which tests for PSP.
In late March, the 62nd Alaska Science & Engineering Fair in Anchorage brought in over 200 submissions. Among them were Ruby Taylor’s examination of the process of extracting sea salt from salt water and Joan Barnowsky’s test for PSP in shellfish.
Both students received awards. Joan won first place in Health and Medicine and also received a Broadcom Masters Award, which pushes her project onto the national level.
Joan’s project is an investigation into the high level of PSP found in shellfish around Kodiak. She says a Kodiak-based scientist comes to Old Harbor frequently to test for PSP and that inspired her project.
“I was interested in clams ‘cause she had a chart that shows the toxicity of the clams, and I saw that, and I saw that they were unsafe, so I decided to test clams myself and help the scientist.”
The scientist is Julie Matweyou with the Marine Advisory Program.
Matweyou says shellfish release more toxins in the spring and summer, and butter clams will retain the toxin and test positive for PSP even during winter months.
She says researchers focus on butter clams because of their popularity for harvest on the island, and she suggested Joan check out other shellfish in the area.
“The idea behind that is that each of these shellfish species are up-taking and retaining and releasing the toxins at different rates. In Kodiak we have more information for the butter clams, so it was of interest to take a look at the other species such as littleneck, cockels, and mussels that Joan was able to find in the same location of collection.”
Joan tested the shellfish for PSP using a commercially available kit called the Scotia Rapid test, and says all of the shellfish tested positive for PSP.
While the test indicates the presence of PSP, it can’t give the tester certainty about whether the shellfish has a safe harvest level of 80 micrograms of toxin for every 100 grams of shellfish.
Matweyou says butter clams consistently do test positive for PSP and never reach a threshold of zero for the toxin.
Therefore, sensitive, yes-or-no tests like the Scotia Rapid Test will be positive even when the shellfish is slightly below the safe harvest level.
“In Kodiak, where we consistently see elevated levels of toxins, the test is less useful because it gets a pass-fail and it doesn’t give us the exact number or toxin concentration that we need to better determine what exactly the test is reading at. It’s sensitive, so it’s reading possibly below the regulatory level at about 60 micrograms of toxin.”
Due to the constant of presence of PSP in Kodiak shellfish, Matweyou says she can’t recommend that people harvest them. Although, of course, they frequently do.
With that in mind, she says she’s partnering up with the Sun’aq tribe of Kodiak, the Native Village of Old Harbor, and the City of Ouzinkie on a new and improved test that people for a safe harvesting routine.
They’re at the beginning of the three-year project and she says the new test will provide a numerical value for the toxin level, rather than just a pass or fail result.
Matweyou says they hope to come up with a marketable test and provide it to local harvesters by the end of the three-year study.