Project: Temporal dynamics of seagrass associated fish and invertebrate populations in Johnson Key Basin, western Florida Bay

Web Site: Temporal and Spatial Variation in Seagrass Associated Fish and Invertebrates in Western Florida Bay

Location: Central Everglades, including Florida Bay; Monroe County

Principal Investigator: Michael B. Robblee, Mike_Robblee@usgs.gov, 305.348.1269

Project Personnel: Joan Browder, Joan.Browder@noaa.gov, 305.361.4270

Other Supporting Organizations: NOAA/National Marine Fisheries Service

Associated Projects: (Joan Browder and Maria Criales), Community Dynamics along a Salinity/Habitat Gradient in Florida Bay (Michael Robblee)

Overview & Status: This project is in year 3 of five years. Its purpose is to extend a quantitative record of seagrass associated fish and invertebrate abundance, including the pink shrimp, using similar methods, that exists for western Florida Bay starting in 1983. Objectives include: developing a quantitative baseline of seagrass associated invertebrate and fish abundance and species composition; relating abundance and species composition to salinity and temperature; comparing invertebrate and fish communities among bank, basin and near-key habitats; relating abundance and species composition to changes in seagrass habitat over time; and evaluating the relationship of pink shrimp abundance in Johnson Key Basin to salinity, seagrass habitat and recruitment. Defining and evaluating restoration actions in terms of biological resources and related issues is a critical science need. Florida Bay is an important shallow marine nursery habitat in south Florida. In the bay salinity patterns, water management, and changing seagrass habitat are interlinked and critical to the bay's nursery function. Seagrasses are central to the bays nursery role: they serve as the dominant primary producer, they provide shelter for larval and juvenile stages of commercially important species and for non-game species which are critical as prey supporting higher trophic levels; they stabilize sediments; and seagrass mediates water column nutrient dynamics. In 1987 a seagrass die-off began in the bay. Following initial dramatic seagrass habitat losses, algal/turbidity blooms and continuing declines in seagrass habitat have characterized Florida Bay. The bay serves as nursery and feeding ground for many important species: the bay supports both of Florida's largest commercial fisheries, the Tortugas pink shrimp fishery and the Florida Keys' lobster fishery; the bay supports a critical sportfishery for seatrout, tarpon, snook, red drum, and other desirable species; the bay serves as critical nesting and feeding ground for many of the wading bird species found in south Florida; and the bay supports endangered species such as the American saltwater crocodile. At present biological databases that exist for Florida Bay are being evaluated for their relevance for developing performance measures and models for relating species of importance in the bay to upstream water management. At this time field collections are current but the processing of samples is behind schedule. Post-larval sampling began in December 1999. A database has been developed and is coming online. QA/QC of existing data and new data will start when the database is complete. All available data have been provided to existing projects where appropriate for the development of performance measures and models. This applies particularly for data on pink shrimp.

Needs & Products: The most important issue related to completing this project on time is to reduce the backlog of samples. Toward this end adequate laboratory space is the most pressing need. At this time USGS at FIU does not have laboratory space. The wet lab space initially promised by Everglades National Park has not materialized. Project personnel and database needs have been met beginning this year. Products will include a baseline data set with which to relate salinity and habitat to species abundance and species composition. Publications relating community and population dynamics to salinity, seagrass habitat, habitat changes related to seagrass die-off and algal blooms will be provided. These data will be used in the development of performance measures and models of the seagrass associated fish and invertebrate community as well as of the pink shrimp. This project is specifically linked to two other projects; the NOAA pink shrimp project and the USGS/NOAA salinity gradient study in Florida Bay.

Application to Everglades Restoration: These tools will ultimately be used in defining and evaluating water management alternatives and once defined and implemented these tools will be used to evaluate success.