From mislabelling to plastic contamination, eating fish isn’t as safe or healthy as most diners would like to believe.

Laura McDonnell is a young fish biologist from Montreal, Canada. Last year she wrote an article for The Walrus, explaining why she no longer eats any fish. It is particularly interesting to read her reasons, coming from the perspective of a scientist who knows fish intimately.

Her primary concern is mislabelling, a rampant problem worldwide. One example:

“Oceana, a United States–based environmental advocacy group, recently compiled the findings of 200 studies and determined that out of 25,700 seafood samples from fifty-five countries, one-fifth were mislabelled.”

Mislabelling is problematic not just because it’s unethical, but also because it is dangerous. Some fish carry toxins and require special handling in the kitchen. Some diners may have allergies and yet not know exactly what they’re eating.

McDonnell’s second concern is plastic. We’ve written about this countless times on TreeHugger, but it’s a message that bears repeating. There is so much plastic in the world’s oceans now — an estimated 244 million kilograms — that fish can’t help but eat it. In fact, research has shown that fish actually prefer plastic to real food.

“For most aquatic animals, finding food while avoiding predators is a struggle, so being picky or discerning is not evolutionarily beneficial; most species grab their desired snack quickly and head right back to their hiding place. As a result, aquatic animals often ingest floating bits of plastic, either by confusing colourful microplastics for something else, or by ingesting plastic-contaminated prey.”

While we don’t yet know what effect ingested plastic will have on our human bodies, it’s not an experiment anyone really wants to try — although, sadly, we’re well on the path to discovering what it will look like.

For those of us living in Canada, the United States, and Europe, we are fortunate to have access to alternative forms of protein, whether it’s meat, tofu, dairy, or beans. But there are many people in the world who do not have the luxury of choice. In her work, McDonnell has visited African villages where fish is the primary source of protein and other options are limited. For these people, the repercussions of pollution, contamination, and dwindling stocks are far more severe.