There’s a lot of plastic waste out there in our oceans, and fish are eating a disturbingly high amount of it. And, it turns out, a good bit of that consumption may not entirely be by accident.
A recent article in Popular Science magazine describes research that Matthew Savoca, a California Sea Grant State Fellow at the National Oceanic and Atmospheric Administration’s (NOAA) Southwest Fisheries Science Center, conducted to help us understand better why fish appear to be attracted to plastics, and don’t merely consume them unwittingly as they eat other foods contaminated with tiny bits of plastic. It may have something to do with smell.
Savoca and his team, including researchers at the University of California-Davis and Aquarium of the Bay, actually began by looking into data on sea birds and how they pursue the food they eat. Some birds appear to be attracted to the smell of a compound in algae called dimethyl sulfide, and those birds that are drawn to this compound eat much more plastic than birds and other animals that don’t rely on it to detect the presence of available food.
Dimethyl sulfide often emerges when the cell walls of algae die, and the compound can infuse plastic materials with its aroma. Algae like to attach to hard, smooth surfaces, and as they float to the surface of the ocean to collect sunlight, they attach to bits of plastic that are floating around with the garbage we human beings negligently discharge into the ocean in large quantities.
What’s this got to do with fish? Savoca and his team turned to anchovies to see if they were attracted to dimethyl sulfide in the same way that certain sea birds are. To make a long story short, it turns out they are. Then, of course, these smaller aquatic animals are eaten by larger fish, and then by humans (and we eat anchovies ourselves).
So it seems that, as the article in Popular Science put it, “something happens to plastic in water that turns it from junk into junk food.” Of course, there’s still more work to do to find out whether other fish are attracted to plastic in this way. I leave it to you to read the article for the full story.