Ocean plastic boosts sea skater numbers

The amount of plastic swirling around in the Great Pacific Garbage Patch has increased 100-fold since the 1970s, altering marine habitats.

And while the tiny pieces of plastic littering the ocean one thousand miles west of California are a known risk to many species, it’s actually been good news for one.

Creatures such as the marine insect Halobates sericeus – also known as sea skaters or water striders — live on the surface of the water and lay their eggs on floating objects. Normally, this means objects such as seashells, seabird feathers, tar lumps and pumice.

However, a new study from the Scripps Institution of Oceanography at UC San Diego shows that sea skaters are now using the plastic garbage as a surface for their eggs, triggering a sharp rise in densities in the region.

It’s the first time such an increase has been documented in a marine invertebrate in the open ocean, and could have consequences for animals across the marine food web, such as crabs that eat sea skaters and their eggs.

“This paper shows a dramatic increase in plastic over a relatively short time period and the effect it’s having on a common North Pacific Gyre invertebrate,” says Scripps graduate student Miriam Goldstein.

“We’re seeing changes in this marine insect that can be directly attributed to the plastic.”

The plastic, though, is bad news for most species. Last year, Scripps researchers found that nine percent of fish in the region had plastic waste in their stomachs.

“Plastic only became widespread in the late ’40s and early ’50s, but now everyone uses it and over a 40-year range we’ve seen a dramatic increase in ocean plastic,” says Goldstein.

“Historically we have not been very good at stopping plastic from getting into the ocean so hopefully in the future we can do better.”