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Red Tide and Reef Fish Modeling

Operationalizing the West Florida Shelf ecosystem model and application to red tides, stock assessment, and catch advice for Gulf of Mexico reef fish

The project team will update and improve upon an ecosystem model of the West Florida Shelf to account for red tide mortality when assessing Gulf of Mexico reef fish. The project will develop new approaches to map red tides using satellites, and biogeochemical models to map oxygen concentrations in relation to red tides. These products will be incorporated into a spatially explicit fisheries ecosystem model to estimate red tide mortality on valuable commercial and recreational species. Estimates of red tide mortality will be incorporated into stock assessments and recommendations on acceptable biological catch, or the amount of fish that can be harvested each year, for reef fish species that will undergo stock assessments between 2024-2028. The acceptable biological catch is a recommendation that accounts for scientific uncertainty and serves to prevent overfishing.

Lead Investigator: David Chagaris, Nature Coast Biological Station, University of Florida (

Natural Resource Managers: Ryan Rindone, Gulf of Mexico Fishery Management Council, and Peter Hood, NOAA Southeastern Regional Office

Project Team: Chuanmin Hu, University of South Florida, College of Marine Science; Michael Stukel, Florida State University, Department of Earth, Ocean, and Atmospheric Science; Sven Kranz, Rice University, BioSciences

Collaborators: Kate Siegfried, NOAA Southeast Fisheries Science Center; Mandy Karnauskas, NOAA Southeast Fisheries Science Center; Skyler Sagarese, NOAA Southeast Fisheries Science Center; Ted Switzer, Florida Fish and Wildlife Commission Fish and Wildlife Research Institute; Michael Sipos, Florida Sea Grant; Casey Streeter, commercial fisherman and founder of Florida Commercial Watermen’s Conservation group; Dylan Hubbard, Captain and co-owner of Hubbard’s Marina

Federal Program Officer/Point of Contact: Frank Parker (

Award Amount: $1,768,147

Award Period: October 2023 – September 2028

Why it matters: The Gulf of Mexico Fishery Management Council is responsible for managing fisheries and habitat in federal waters of the Gulf of Mexico, including 31 species in the reef fish complex. There is often considerable uncertainty when specifying the acceptable biological catch, and ongoing or recent red tide blooms caused by the toxic dinoflagellate, Karenia brevis, are a primary source of  uncertainty in catch projections used to manage reef fish stocks. Determining how much fish can safely be harvested each year is an important fisheries management decision with major consequences on the health of fish stocks and the fisheries that target them.

What the team is doing: The team will draw upon three previously funded NOAA RESTORE projects to combine fisheries ecosystem and biogeochemical modeling with large scale fisheries and habitat surveys, with the addition of remote sensing. The team will 1) develop red tide maps using NOAA’s VIIRS satellite instrument; 2) incorporate oxygen and red tide dynamics into a physical biogeochemical model; 3) update and calibrate the West Florida Shelf (WFS) Ecospace model; and 4) operationalize the WFS ecosystem model for routine stock assessment and management. The project team will also develop an online questionnaire to facilitate collection of local ecological knowledge from fishers and complement model predictions with on-the-water accounts of red tide impacts. 

Expected outcome: The project is expected to support acceptable biological catch determination for multiple species under the Gulf of Mexico reef fish fishery management plan that will undergo stock assessments from 2023-2028. This project will also help inform fishery management plan amendments and contribute to the implementation of the Gulf of Mexico Fishery Ecosystem Plan process as it works through its first Fishery Ecosystem issue.