What's Associated with Deep-sea Corals and Sponges?

The deep sea appears far-removed from anthropogenic impacts, yet deep-sea habitats face some similar threats to shallow-water habitats such as fishing stress, ocean acidification, and pollution. Deep-sea coral and sponge ecosystems are often hotspots of biodiversity, providing habitat for many invertebrates and several fish species, including commercially important ones. Thus, species that are vital to the U.S. economy may also be threatened by fishing activity and other anthropogenic impacts such as marine debris. Few studies examine the relationship of anthropogenic debris with deep-sea coral and sponge habitats because these ecosystems are so difficult to study. I conducted an image and video analysis of anthropogenic debris in the deep sea to examine its association with corals and sponges, mainly in the U.S. Northeast, Southeast, Gulf of Mexico, and Caribbean regions. The largest category of observed debris was plastic (27% of debris annotated). 52% of the observed debris was seen in canyons, and 49% of debris was associated with corals or sponges. Several debris items were entangled around corals and sponges or produced drag marks, suggesting they are moving with currents, potentially moving invasive species around the globe. Images of debris and managed species associated with deep-sea corals and sponges can be used to inform policy and the public on the importance of protecting deep-sea coral habitats from anthropogenic impacts using tools such as Habitat Areas of Particular Concern and Marine National Monuments.