Why Do Fish Eat Plastic?


When you enjoy a bite of fish, you’re probably not thinking about what your food spent its life eating. Now, however, you may need to.

Researchers have found 100 species of fish that consume plastic trash in the ocean. Because the plastic does not fully biodegrade, it becomes absorbed into their body tissue and accumulates over time. Although plastic does not generally kill the fish that eat it, it does have other negative health effects, such as reduced liver functionality and reduced overall activity.

This becomes an issue for humans because when we eat a fish with plastic in its system, that plastic is likely to accumulate in our bodies, too.

Plastic in the ocean is a well-documented environmental problem. What we don’t understand as well is why fish are drawn to eat the plastic in the first place. One study shows that smell may be a key factor.

In the experiment, anchovies responded to the smell of plastic debris in their seawater just as they did to floating krill (their typical food) and actual plastic debris — with movements indicating they were searching for food. The anchovies perceive the smell of plastic debris as a potential food signal. This doesn’t tell us exactly why they are eating the plastic. However, it does tell us that the appearance and smell of plastic is confusing to them, so they are likely to continue eating it if it remains in their habitat.