Course:FNH200/Projects/2026/Poisoning in Oysters

Team Introduction

This page is for GROUP 25 from FNH 200 942 (Summer T2 2026). Our team members are as follows:

• Joshua Hart
• Ahaana Mitra
• Julian Renzetti
• Leah Song
• Tyler Tran

Background Information

Our selected topic of choice was about safe oyster production and consumption in British Columbia. As noted by Statistics Canada, BC is Canada's largest producer of oysters, topping out at roughly 7,200 oysters in 2024. The BC Shellfish Grower's Association also wrote that BC is the 12th largest producer of Pacific oysters in the world, operating under strict regulations and sustainable farming practices. As a result, it is no surprise that we wanted to do a deep dive into how oysters are consumed in Canada, some of the unique processing procedures for farming and selling oysters, and noteworthy safety hazards when it comes to consuming oysters in BC.

Oyster Consumption Habits in Canada

Common raw oyster recipe

It's the question everyone asks at some point before consuming this seafood delicacy - how do you eat an oyster? In BC, most consumers eat oysters raw on a shucked half-shell, perhaps with other condiments as desired, although there are several popular recipes in eating them baked, grilled, or fried. You can find the freshest oysters in-season from October to May along the West Coast, and local companies such as Fanny Bay Oysters are renowned worldwide for their Pacific varieties, hence our interest in what sets BC's oyster industry apart from others around the world.

However, there are specified limits to how many oysters you can consume! Oysters are a known source of cadmium, given that oysters are filter feeders by nature. In particular, the BC coastline has some of the highest reported levels of cadmium in Pacific Northwest oysters, ranging from 1-4 ppm. Prolonged cadmium intake puts consumers at risk of kidney malfunction and bone density loss, as stated by the BC Centre for Disease Control. As a result, Health Canada does not prescribe high-risk groups (pregnant women, young children) to consume oysters and for adults to cap their monthly limit at a maximum of 12 oysters.

Oyster Farming in BC

Oyster tray culture

Most of BC's oyster industry focuses on sustainable farming, as opposed to wild oyster harvesting, with everything taking place on BC's coastlines. Farming first begins by breeding oyster larvae into seeds by using specialized tanks. Afterwards, these seeds are then placed in a "flupsy", or a floating containment area (as shown on the right) within ocean waters to allow oyster culture to filter for nutrients derived from algae and other marine plants. These nutrients may include calcium carbonate, which builds up the characteristically thick protective shell of the oyster. Upon reaching the juvenile stage after approximately one year, oysters are then transferred into larger "growout systems", where they will reach adult stage after another two years. These systems include separate trays and cages which can be individually handled to harvest each rack once the oysters are matured.

Current Events in BC Oyster Industry

Campylobacter jejuni bacteria

While BC is well-known for their high-quality oyster processing standards, many advocates for food safety have called out the provincial government on multiple outbreaks stemming from active oyster harvesting areas in BC such as Baynes Sound. These outbreaks range from norovirus (AKA stomach flu) to bacterial infections such as campylobacter, which is generally correlated to raw meats and unpasteurized dairy products. Further investigations have found evidence of improper sewage treatment and disposal which have contaminated oyster farming areas, thereby causing many recalls and public health concerns throughout British Columbia.

Alongside from the rising risk of consuming contaminated shellfish, there's several cases of massive oyster die-off events in BC from Pacific oyster-specific diseases. This prompted unease amongst researchers and oyster farmers alike, along with calls to improve BC's current aquaculture standards to make the BC oyster industry more resilient to the impacts of rising ocean temperatures, contamination events, and foreign spat (seed) transplants.

Paralytic Shellfish Poisoning (PSP)

Context and Origin

PSP is a type of poisoning that can occur from the consumption of various bivalve shellfish. It can also occur in lobsters and crabs that feed on infected shellfish. Because shellfish feed by filtering microscopic organisms from the water, they ingest all kinds of organisms from their environment indiscriminately. The toxins within these organisms can build up in the system of the shellfish, reaching levels that are toxic to humans. Interestingly enough, these toxins do not appear to have any impact on the shellfish themselves. PSP specifically is caused by the buildup of neurotoxins in the water, which are produced by algae from the genus Alexandrium, Gymnodinium, and Pyrodinium.

Symptoms and Treatment

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Climate Change Impact

Harmful Algae Blooms

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Future Outlook

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Regulations and Future Improvements

Quality Assurance of BC Oysters

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Canadian Shellfish Sanitation Program (CSSP)

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Improving Oyster Processing Regulations

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Addressing Climate Change Policy

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