Farmed Oysters Aren't Dirty Filters

I have loved shellfish for a long time. Oysters most of all. So when people call them dirty sewage filters, it gets under my skin.

Sydney rock oyster on the half shell with two empty shells — Oysters on the half shell. Photo: Pelagic / Wikimedia Commons. CC BY-SA 4.0. Commons file.

Most oysters you eat are farmed. That is usually a good thing. They are not pulled from random ocean water. In Canada, farmed oysters fall under the Canadian Shellfish Sanitation Program. The water gets tested before harvest. If the water looks bad, the area shuts down. Same idea in BC, PEI, and the other growing spots.

Stacked oyster farm boxes from Cap Ferret — Oyster farm boxes. Photo: Víctor Perea Ros / Wikimedia Commons. CC BY-SA 4.0. Commons file.

They do not “eat” sewage the way that myth sounds. Oysters filter tiny plants and bits of food from the water. They spit out a lot of what they do not want. Farms also stay away from sewage pipes and dirty industry on purpose. Bad oysters would fail the tests. They would not make it to the plate.

There is still risk if your immune system is weak. I am not waving that away. But oysters are also one of the most filling, healthy foods you can eat. And when they are good, they taste great. BC and PEI farms are the ones I think of first.

I am not a scientist. I am not quoting exact legal limits here. For me the short version is simple: farmed oysters are not the dirty-filter story people like to tell.

Next time someone turns up their nose at oysters, I will keep eating mine.

Stay tuned… happy to point people at places that do shellfish right.