By Michelle Gamage, Local Journalism Initiative Reporter THE TYEE
When it香蕉视频直播檚 feeding time, Vancouver Island University biology student Chloe McLaughlin carefully scoops a palm-sized green sea urchin out of a tank.
Flipping it upside down, she exposes the creature香蕉视频直播檚 mouth and gently feeds it a biotoxin that is highly poisonous to humans.
The biotoxin, also known as paralytic shellfish poison, affects only creatures with central nervous systems, she says. Potentially lethal to humans, it doesn香蕉视频直播檛 hurt sea urchins or other bivalve filter feeders such as oysters, clams, scallops, mussels and cockles.
This experiment is part of a larger collaboration between the Canadian Food Inspection Agency and Vancouver Island University to improve testing for biotoxins in seafood and ultimately improve food security for remote and Indigenous communities along the coast, says lead researcher Timothy Green, VIU香蕉视频直播檚 Canada Research Chair in shellfish health and genomics.
Coastal Indigenous communities are at higher risk of being affected by paralytic shellfish poison because their diets rely more heavily on seafood than those of the general population, Green says. A person in Bella Bella, for example, eats about 24 times more seafood than someone in Kelowna.
Harvesting, eating and sharing traditional foods supports the culture, community and public health of First Nations. And there may not be other healthy or affordable food sources available. A study published this winter also found that reducing how much seafood a First Nations person could eat in B.C. increased their risk of heart disease.
There are ongoing Indigenous-led initiatives working to test and identify hazards in their own waters too, like the We All Take Care of the Harvest project run by the First Nations Health Authority, and biotoxin testing labs set up by Southeast Alaska Tribal Testing program.
McLaughlin is exposing sea urchins to paralytic shellfish poison, or PSP, to see if they bioaccumulate the toxin to dangerous levels. If they don香蕉视频直播檛, sea urchins can continue to be relied on as a safe, alternative food source for Indigenous communities when shellfish harvesting gets shut down due to biotoxin risk, Green said.
The ultimate goal is to create a portable and accessible testing kit that can be widely distributed to remote communities to accurately test for biotoxins that can be lethal when consumed but have no taste or smell and can香蕉视频直播檛 be cooked off, Green said.
These biotoxins can remain in clams for two years after the animals are exposed, he added.
香蕉视频直播淐ould we eventually get a test that香蕉视频直播檚 reliable and easy to use like a pregnancy test or COVID RAT rapid antigen test into Indigenous communities which could tell people if the seafood is safe to eat? That香蕉视频直播檚 our aim,香蕉视频直播� Green said.
These tests would need to check for hundreds of biotoxins, but Green is optimistic. 香蕉视频直播淏right ideas happen all the time,香蕉视频直播� he said.
How biotoxin testing currently works
Currently there香蕉视频直播檚 only one lab in Western Canada that tests Pacific shellfish for biotoxins, says Carolyn Bateman, director of the CFIA Burnaby laboratory.
The lab tests for toxins that cause paralytic shellfish poisoning, amnesic shellfish poisoning and diarrhetic shellfish poisoning.
When an area is declared safe, harvest can be allowed 香蕉视频直播� so long as it香蕉视频直播檚 the right season and harvesters have rights or a licence to harvest in an area. The BC Centre For Disease Control and Fisheries and Oceans Canada both have maps that show what areas are open for harvest. The Can U Dig It app is a free, mobile-friendly version of the DFO map.
Bateman said the current testing method is 香蕉视频直播渆xpensive, complex and infrastructure heavy香蕉视频直播� and requires highly trained chemists to prepare live samples for testing on 香蕉视频直播渧ery expensive chemistry instruments.香蕉视频直播�
Adding to the overall cost, it香蕉视频直播檚 beneficial to have a couple of backup machines in case one goes down and takes days to repair, she said.
While the test results are accurate, Bateman says, the testing process is slow, and cost-prohibitive for remote communities. The remoteness of some communities also creates barriers to shipping live samples to the lab, she added.
Testing for PSP means testing for 12 toxins and seeing how each one contributes to overall toxicity in people, Bateman said. In mild cases it can cause numbness in the mouth and limbs, and in severe cases it can cause incoherent speech, respiratory paralysis and death, according to DFO.
PSP is one of the most potent natural poisons in the world and has no known antidote, DFO says.
Amnesic shellfish poisoning, also known as domoic acid poisoning, causes severe nausea, vomiting and diarrhea within six hours, and within 48 hours can progress to neurological symptoms like disorientation, memory loss, coma and death, according to the Washington Department of Fish and Wildlife.
Diarrhetic shellfish poisoning 香蕉视频直播渇eels like you香蕉视频直播檙e going to die but you will survive,香蕉视频直播� Bateman said. It causes diarrhea, nausea, vomiting and cramps.
PSP is caused by red tide, which happens when there is a bloom, or explosion in population, of single-celled plants known as phytoplankton that live in the ocean. As bivalves feed on the phytoplankton, the toxin accumulates in their bodies.
The Burnaby CFIA lab tests all shellfish in B.C. If you香蕉视频直播檝e enjoyed local mussels at a restaurant or bought oysters from a fishmonger, you香蕉视频直播檝e got Bateman香蕉视频直播檚 team to thank.
Shellfish testing has largely been built around the commercial harvest, Green said. Shellfish farms tend to be set up along accessible shipping routes, making it easier to ship animals in for regular testing. By comparison, shipping seafood from remote communities takes a week at best, which increases the chances the shellfish arrive dead and can香蕉视频直播檛 be tested.
Warming oceans are supporting more frequent red tide blooms and the season is getting longer, starting during a warm spring and lasting into the fall, Bateman said.
It香蕉视频直播檚 also possible to have a red tide that doesn香蕉视频直播檛 produce any biotoxins or a very minor bloom that produces a lot of toxins, she said.
Different bivalve species take up the toxin differently. Mussels are quick to absorb the biotoxins but also quick to purge them from their system, Bateman said, while butter clams hold on to toxins for quite a long time.
If someone is poisoned by PSP and is able to get emergency medical care, it香蕉视频直播檚 possible to be put on a respirator while your body works through the toxin, Bateman added 香蕉视频直播� but remote communities might not have access to these emergency health services.
Anyone who eats shellfish and experiences tingling in their mouth, jaw or hands should call 911 or poison control right away.
Canada is a bit of a 香蕉视频直播渉ot spot香蕉视频直播� for marine biotoxins, Green said, 香蕉视频直播渁nd it香蕉视频直播檚 getting worse.香蕉视频直播� Marine heat waves like the Blob are associated with biotoxin blooms.
Without accessible and reliable testing, Green said, remote communities are forced to adopt strategies like having the largest member of the community take a 香蕉视频直播渘ibble香蕉视频直播� to see if they get sick 香蕉视频直播� the safety measure being that their larger body means they can handle more toxins.
It香蕉视频直播檚 not fair to force communities to resort to this in the 2020s, Green said. 香蕉视频直播淲ithin the decade we hope to have something better to mitigate risks.香蕉视频直播�
Improving testing
One big bottleneck Green and Bateman both pointed to is how shellfish samples have to be shucked and prepared at the Burnaby lab.
Shucking needs to be done carefully. If a bivalve香蕉视频直播檚 guts are ruptured, it can change the pH of the tissue and create false test results, Bateman said.
The Canadian Food Inspection Agency is working with Vancouver Island University to create a second lab where shellfish can be processed and then shipped to the Burnaby lab for testing.
Bateman said this second lab will also be used to train new chemistry analysts who can help speed up testing.
Green said another possible solution that is being explored at VIU is using mass spectrometry to test samples dabbed onto paper. Mass spectrometry creates a reading of every single molecule in a sample, allowing researchers to then check for the presence of toxins.
Mass spectrometry is used as the gold standard for drug testing.
Dabbing a sample on paper could mean only the paper needs to be shipped to a lab for testing, Green said.
McLaughlin is trying to see if green sea urchins absorb PSP into their gonads, also called 香蕉视频直播渦ni,香蕉视频直播� which can be a valuable food source as they are high in protein and omega-3 fatty acids, similar to salmon.
Sea urchins are herbivores, grazing on kelp and other seaweed. Under normal circumstances, they don香蕉视频直播檛 eat food sources that contain biotoxins, so toxins don香蕉视频直播檛 bioaccumulate in their bodies, McLaughlin said.
They can be harvested year-round, according to DFO, with a valid B.C. tidal waters sport-fishing licence. Some Indigenous fishers may have rights to harvest without a licence.
In recent years there香蕉视频直播檚 been a huge die-off in sea urchins香蕉视频直播� natural predators, such as sunflower sea stars, which has allowed sea urchin populations to explode. Urchins will eat all the seaweed in an area, creating what is known as an urchin barren, with no food sources left.
McLaughlin said a handful of urchins have been found around the world with biotoxins below the reportable limit of 80 micrograms per 100 grams of tissue 香蕉视频直播� any higher and there could be a risk to humans, she added.
How those urchins bioaccumulated those toxins and whether it香蕉视频直播檚 possible for urchins to contain dangerous toxin levels are some of the many questions McLaughlin is hoping to answer through her research.
If sea urchins are starving, they will adopt an omnivorous diet and will eat dead things or forage for whatever they can find, such as algae and other animals, McLaughlin said, which could increase their risk of containing paralytic shellfish toxin.
香蕉视频直播淲e need to know how to inform people whether it香蕉视频直播檚 safe to harvest,香蕉视频直播� Green said.
香蕉视频直播淚f you say `Don香蕉视频直播檛 eat clams,香蕉视频直播� what is the alternative food source? Is it healthy? Clams are healthy.香蕉视频直播�
