Marine debris facilitates the long-distance dispersal of fish species

Drifting marine debris has been shown to host associated biological communities and facilitate their dispersal. Little is known about how biota engage with, and are transported by, this debris. This study characterizes debris-associated communities and explores the role of plastics in transferring fishes to new geographic regions. similar to 1500 underwater photographs were reviewed from five cruises during 2018-2020: one between Japan and Hawaii encompassing the Western and Eastern Pacific Ocean (Group I), and four passing through the North Pacific Garbage Patch in the Eastern Pacific Ocean (Group II). Debris properties were recorded and 13 associated fish species from 43 debris items were identified. Fish communities around marine debris have low diversity, individual debris items have highly dissimilar species compositions, and species composition is affected by horizontal debris item size. Debris items in Group I have significantly higher fish species diversity and differ in community composition from Group II. Four taxa (Abudefduf vaigiensis, Histrio histrio, Oplegnathus punctatus, and Petroscirtes spp.) were observed surviving east of the Hawaiian Islands, where they have not been previously reported. Marine debris is found to be a mobile natural habitat substitute that can facilitate long-distance species dispersal. While natural flotsam has long been a potential vector, long-lived and increasingly abundant plastic debris may set the stage for altering fish biogeography.