Even among people who identify as vegan, there can be a spectrum of what they will or will not do. Many vegans don’t consume or use anything derived from any animal under any circumstances, but others will eat honey or wear vintage leather. And there’s a small but growing subset of people who are otherwise vegan that are opting to consume oysters and other bivalves (mussels, clams, and scallops).
These people are officially called ostrovegans or bivalvegans and their stance is, essentially, that these hinged-shell-dwellers lack the sentience of other animals so no suffering is caused by eating them.
Sentience means a creature can perceive or feel things due to a central nervous system. An animal must be sentient to perceive their surroundings and feel sensations. Bivalves are categorized as being non-sentient because they don’t have central nervous systems. They have nerves, but they don’t have brains. Just as scientists have concluded that plants don’t experience pain, the same is believed to be true for bivalves.
Oysters and mussels are sessile (unable to move by themselves) while clams and scallops are motile (able to move). The latter can respond to external stimuli, such as a scallop swimming, but scientists consider that movement similar to the way a venus fly trap opens and closes or how sunflowers follow the sun.
“I’m comfortable eating all bivalves, I was raised in a coastal town so they’ve always been a part of my diet,” says Essie Somma. Somma went vegan in 2018 and started eating bivalves in 2020. “Knowing they’re non-sentient allows me to reincorporate them into my diet without abandoning my morals. I’ve chosen to be plant-based and consume bivalves because it’s morally, ethically, spiritually, and physically comfortable for me.”
Understandably, it’s not a stance everyone in the community agrees with. For many, the very definition of veganism is avoiding consuming anything that was once a living animal, regardless of sentience.
“I went vegan to expand my compassion to all living beings,” Iye Bako says. “I wouldn’t eat oysters because while people debate their sentience, the truth is all of Mother Nature is living. It’s not vegan to intentionally look for gray areas and loopholes and exploit them.”
Lauren Yakiwchuk is a life-long plant-based eater and says she too would not consider bivalves. “I feel that it’s a more eco-friendly decision to not eat any seafood,” she says. Other vegans echo a similar sentiment about sustainability. “I prefer not to disrupt the ecosystem bivalves are a part of helping, as they’re an important part of water filtration,” writer Sara Blair says.
Nonetheless, the idea that consuming bivalves could be ethically consistent with veganism has been around for decades. It was popularized by philosopher and activist Peter Singer in 1975 when his influential text on animal rights, Animal Liberation, debuted. In the book, Singer argued that eating sessile bivalves is acceptable on a vegan diet. However, in later years, Singer changed his mind on the matter. He has updated the text in recent printings of Animal Liberation to clarify that he no longer endorses bivalveganism, taking the stance that we might not know enough about their ability to feel pain.
For some ostrovegans, there are nutritional motivations. Oysters are dense with nutrients that can be difficult for vegans to consume through plants. “There are many reasons to love oysters,” Rima Kleiner, MS, RD, and blogger at Dish on Fish, says.
“Nutritionally speaking, oysters are rich in protein, vitamin D, zinc, iron, and copper,” Kleiner adds. “Oysters are packed with protein, 8 grams, and provide about 70 calories in a 3-ounce serving. Plus, oysters are low in fat and carbohydrates, yet full of beneficial nutrients, like omega-3s, selenium, and vitamin B-12.” Bivalves are also a source of heme iron, magnesium, vitamins C and E.
Oyster-eaters also note the importance of the creatures to their aquatic environments. Oysters filter out excess nitrogen and purify the water they’re in since they eat phytoplankton and algae which filters pollutants from the water and supports the ecosystem.
That’s the philosophy behind plant-forward but bivalve-embracing restaurant Oyster Oyster in Washington D.C. It takes its name from the idea of oysters being served alongside oyster mushrooms. Chef Rob Rubba explains that oysters are a critical part of the ecosystem in the Mid-Atlantic.
“For the past century, oysters were overharvested, which lead to a snowball effect of environmental collapse of our watersheds,” he notes.
“Oysters need a ‘reef’ to grow on and that reef needs oyster shells, as an oyster will only attach and grow to another oyster,” Rubba explains. Oyster reefs are not made of coral, but gatherings of linked oyster shells growing together, typically attached to rock formations. Once common around the world, these reefs have disappeared or been damaged by unsustainable practices. “Eating local, ‘farmed’ oysters allows us to not impact the current wild reefs, while also allowing us to rebuild a stock of oyster shells to return to the water and contribute to rebuilding these oysters reefs.
Chantale Lamarche went vegan four years ago over environmental concerns. Recently, she has added bivalves, mostly oysters and occasionally mussels, to her diet. “Finding out that oysters and mussels clean the water was the ticket to them coming back on the menu,” she says. “Oysters filter water to feed, and farming oysters helps the environment twofold because farmed oysters help the wild populations replenish.”
When farmed and harvested responsibly, commercial oyster, clam, and mussel cultivation avoids the bycatch and harm to sentient aquatic life associated with other seafood, and is typically done without the use of antibiotics or animal-based feeds. Scallops, it should be noted, are often wild-caught and therefore may not be considered as environmentally sound to consume.
If one does decide to consume oysters, Rubba recommends seeking out responsible providers close to where you live. “It’s important to support and eat local oysters, as it cuts down on carbon emissions and other waste involved in shipping.”
Ultimately, it is up to each individual to decide what kind of consumption they feel is appropriate, and that may differ by what inspired one to go vegan in the first place. People motivated by personal health, environmental sustainability, or concern for animal rights may find they land in different places on the issue. According to The Vegan Society, the best definition of veganism is “a philosophy and way of living which seeks to exclude — as far as is possible and practicable — all forms of exploitation of, and cruelty to, animals for food, clothing or any other purpose.”