Advisories have been in place for the better part of the summer at two Kodiak beaches due to concerns over paralytic shellfish poisoning. Environmental staff with the Kodiak Area Native Association (KANA) test water samples along with a variety of species once a week to monitor toxin levels in shellfish and update these advisories.
Kasey Jo Wright wades into the water at Mission Beach on the morning of July 10. High tide is coming in as Wright, an environmental technician with the Kodiak Area Native Association, drags a cone shaped mesh net that looks like a wind sock through the water, at a specific depth in the water column without touching the bottom.
“These nets are 20 micrometers wide, the weave between them. So that’s small enough for your basic bacteria, water, and other tiny micro particles are going to go through," Wright explained.
Wright and her colleague Celeste Ossowski, do a net tow for three minutes once a week at three locations around Kodiak. Those include Mission Beach, South Trident Basin at Near Island, and Frye Point, which is also known as Sometimes Island. She is testing the levels of phytoplankton in the water to see if saxitoxin, which causes paralytic shellfish poisoning, or other types of toxins from phytoplankton are showing up in areas where shellfish are harvested.
“The purpose of these is not to collect the water but to collect the phytoplankton. So we aren’t going to dry them, so we get the water with them. We do two different processes," Wright said.
Part of that process is filtering water through the net with the phytoplankton and filling about 250 ml of water into a bottle at the bottom. There are two bottles for each of the three sites, and each is labeled with the name of the site it came from. Wright also records the water temperature and salinity along with conductivity before leaving each of the three sites.
The environmental technicians also use a PH monitor at each beach, along with a refractometer to read salinity, which involves putting water droplets on the instrument and then pointing it at the brightest point in the sky while looking through the lens.
During one of these weekly tests at South Trident Basin at the end of May, Wright found evidence of a harmful algal bloom which can cause paralytic shellfish poisoning (PSP). PSP can be fatal for humans. So a warning was issued to residents about the potential dangers of eating shellfish from the area. Harmful algal blooms are due to a higher concentration of various phytoplankton that produce toxins, like the ones Wright is monitoring for.
An advisory for all shellfish species at both South Trident Basin and Mission Beach has been in effect most of July and for the majority of the summer. That’s because the toxin levels found in sampled shellfish at both of those areas exceeded the federal Food and Drug Administration’s regulatory limit of 80 micrograms per 100 grams. But so far no advisories have been reported at Frye Point or Sometimes Island.
This level of toxins can cause PSP if the shellfish is consumed. Wright said her tests would have to result in levels below the regulatory limit before any advisory is lifted at a local beach.
“I think for South Trident Basin, even if it goes under this week, we would keep just an advisory on the phytoplankton updates," Wright stated. "Simply because blue mussels are the fastest one to expel it. So we don’t want to give a false sense of security.”
Wright also takes about a hundred grams of a tissue sample from blue mussels at each of the three sites to test for toxins.
Steve Kibler is an oceanographer at NOAA’s National Ocean Service Lab in Beaufort, North Carolina. He has worked on various projects involving harmful algal blooms and shellfish in Kodiak in the past. Kibler said blue mussels are used for local sampling mainly because of how quickly they release toxins out of their systems.
“They don’t tend to hold on to toxins for long periods. I think in general mussels respond to a bloom, you can detect toxicity within a week or so, just a few days sometimes. And after the bloom goes away, the toxicity drops off very quickly so they are a good sentinel for that,” Kibler explained.
Blue mussels are very different from butter clams, which are popular to harvest on Kodiak Island as well. This species retains some level of toxicity for months, even a year, according to Kibler.
Residents can test their harvested shellfish through KANA’s harvest and hold program. Wright and her colleagues send the samples to a lab in Sitka for free testing. The Environmental Team notes that testing is the only way to know for sure if your wild shellfish harvest is safe from toxins. However, the results from the Southeast Alaska Tribal Ocean Research, or SEATOR, typically take at least two days to come back to Kodiak. And Wright said blue mussels usually aren’t able to survive out of water for that long.
So in some cases, she said residents just harvest the shellfish anyway and risk it. Wright said someone recently asked her for a testing kit that they could use by themselves, but she said KANA Environmental doesn’t have something like that.
“Wright: Here’s what we can do - I can’t do that [testing kit]. Let’s meet halfway. What you harvest, we can get you the results back. He’s like uh, no thanks. And I said ‘I know, I’m sorry.'
KMXT: So then, they would rather risk it at that point?
Wright: They would rather risk it than wait or go through these extra steps, even if it’s free."
Wright and her team encourage residents to check KANA’s latest phytoplankton update before harvesting shellfish from Mission Beach, South Trident Basin, or Frye Point.
Anyone can also submit a portion of their harvested shellfish for free testing by contacting KANA’s Environmental Team via email environmental@kodiakhealthcare.org or 907-486-1362.
