Gulf Islands Seagrass Habitat

Lead Investigator: M. Zachary Darnell, The University of Southern Mississippi (USM) (zachary.darnell@usm.edu)

Natural Resource Manager: Bruce Leutscher, National Park Service (NPS); Whitney Granger, NPS

Project Team: Kelly M. Darnell, USM; Patrick Biber, USM; Gregory A. Carter, USM; Carlton P. Anderson, USM; Kevin Boswell, Florida International University (FIU); Ben Binder, FIU; Jonathan Lefcheck, BEAR LLC; Ali Robertson, Gulf of America Alliance

Collaborators: 

Technical Monitors: Ian Zink (NOAA Southeast Fisheries Science Center, Holly Plaisted (National Park Service)

Federal Program Officer/Point of Contact: Caitlin Young (caitlin.young@noaa.gov)

Award Amount: $3,059,252

Award Period: October 2025 – September 2030

Why it matters: The Gulf Islands National Seashore (GINS) is a series of islands in Mississippi and Florida that are home to large seagrass meadows and diverse assemblages of fish and invertebrates. Seagrass meadows support fisheries by providing habitat, food, and refuge for commercially important species such as red drum and spotted seatrout. However, increases in temperature and nutrient runoff, decreases in light, and changes to salinity are causing widespread declines in seagrass cover. Seagrass loss is associated with declines in fisheries landings, prompting a need for a whole-habitat approach to managing these natural resources. The goal of this project is to identify and monitor long-term trends in seagrass habitats to detect drivers of change within GINS and inform management of these habitats.

What the team is doing: The team will conduct sampling of water quality, seagrass condition, and nekton abundance at different timescales throughout the project in order to monitor trends throughout GINS. They will add water quality sensors to an existing array of stations to continuously monitor water temperature, salinity, dissolved oxygen, and turbidity. Using satellite and aerial imagery, the project team will map seagrass extent and landscape characteristics using aerial and satellite imagery twice during the study. To complement their mapping efforts, the team will also conduct annual monitoring of seagrass meadows to assess seagrass cover. The annual monitoring will include reproductive surveys to identity areas where seagrasses are reproducing within GINS. The team will use trawl and epibenthic sled surveys to measure the composition, diversity, and abundance of aquatic faunal communities within seagrass beds. Additionally, the team will non-invasively sample faunal communities using sonar and by assessing soundscapes using passive acoustic monitoring.

Expected outcome: The team will develop ecosystem models to examine linkages between environmental variables, habitat characteristics, and aquatic faunal communities. The results of this study will be used in the development of GINS’s first ever Marine Management Plan. The team will convene an advisory group with other interested resource managers from federal and state agencies to communicate their findings more broadly.