Examining Microplastic Occurrence in the Gut Contents of Sargassum-Associated Juvenile Fishes

The University of Southern Mississippi investigated the ingestion of marine microplastics in juvenile fish that use floating Sargassum (brown algae) as nursery habitat in the Gulf of Mexico.

Project Dates: July 2014 - August 2016

Who is involved?
Researchers from the University of Southern Mississippi conducted field collections and research out of the Dauphin Island Sea Lab, with funding from the NOAA Marine Debris Program through a NOAA Cooperative Institute with the Northern Gulf Institute.

What is the project and why is it important?
Sargassum, a floating brown algae, creates structure in the open ocean which serves as a nursery habitat for many larval and juvenile fish species, providing both protection from predators and enhanced feeding opportunities. These habitats are used by over 80 species of fish, many of which are commercially and ecologically important such as mahi-mahi, grey triggerfish, butterfish, and flying fish. As a near-surface habitat, Sargassum is subject to the same oceanographic processes that aggregate floating objects including marine debris.

With funding and support from the NOAA Marine Debris Program through a NOAA Cooperative Institute with the Northern Gulf Institute, this research project by the University of Southern Mississippi examined if Sargassum-associated juvenile fish in the Gulf of Mexico are ingesting microplastics, and if so, how frequently this occurs for different species. In addition, this study described the natural diet of Sargassum-associated fish species; this identified prey species that should be examined in the future for a possible role in introducing microplastics into the food chain.

The results of this study identified the species-specific risk of microplastic ingestion. It helped the NOAA Marine Debris Program to further determine and assess the impacts of marine debris on the marine environment in the Gulf of Mexico.