Which Tidal Creeks Make the Best Snook Habitats?

Fish and Wildlife Research Institute (FWRI) scientists are trying to identify the habitat features associated with the most productive common snook (Centropomus undecimalis) nurseries in Tampa Bay. This information is important because it helps environmental resource managers protect targeted areas that are important for supporting healthy populations of snook within the Tampa Bay estuary. Protecting these nursery areas should ultimately help increase the numbers of snook in Tampa Bay and help support and maintain a recreational fishery that generates revenues of over $1 million annually. Before adult snook make their way out into the open water of Tampa Bay where most fishing activity occurs, they use tidal creeks as both nurseries and primary habitat for juveniles. With the help of partners at the U.S. Geological Survey and the University of South Florida College of Marine Science, researchers have identified several “hot spot” tidal creeks that have the potential to contribute relatively more individuals to the snook population in Tampa Bay.

This study is investigating the key features of one of these hot spot tidal creek systems within the Little Manatee River basin. The research uses fish otoliths (earstones) as natural recorders of habitat use during early life stages. As the fish grows, their otoliths are deposited in sequential layers, the chemical composition in each layer can help confirm the locations of prime snook nurseries within Tampa Bay tidal creek systems. The elemental composition within otoliths comes from the elements present in the water mass where a fish resides. The chemistry of water masses differ because of differences in geological setting, land use in the watershed, and the tidal mixing of fresh and estuarine waters. Therefore, the chemistry of a water mass within a tidal creek is likely unique to that system, and allows researchers to develop a chemical “fingerprint” of habitat use in juvenile snook. The chemical fingerprinting is accomplished by measuring the otolith chemistry of newly caught juveniles comparing that to the chemistry of the central (core) area of adult snook otoliths, and then matching the chemistry of the fish otolith to the chemistry of a tidal creek.

The habitat researchers have set out to achieve two goals: 1) characterize the range of conditions and habitats in which juvenile snook reside 2) identify distinct ecological and structural features that are associated with priority snook nursery habitats. Once these nurseries are identified, they can be protected and restored where needed. Restoring and conserving the most productive snook nurseries should lead to higher numbers of these fish in Tampa Bay, enhancing the recreational snook fishery.