In 2013 FWC Division of Freshwater Fisheries Management (DFFM) partnered with the Southwest Florida Water Management District (SWFWMD) on the Springs Coast Fish Community Assessment Project. During the Springs Coast project significant seasonal differences were documented in fish species composition. Rivers with direct connection with the Gulf of Mexico exhibited a seasonal shift in fish species composition, depicting an increase in marine species and a decline in freshwater fish species relative abundance during winter months. Of these systems, the influx of marine species was most evident in the Homosassa River system. Following completion of the Springs Coast project we chose to further investigate the drivers of these seasonal shifts using the Homosassa River system as our pilot river. The role and use of spring-fed systems by marine fishes along Florida’s Gulf coast is poorly understood. We aim to determine the effects of seasonal abundance shifts on freshwater fish species dependent upon the Homosassa River for forage, refuge, and reproduction through examination of fish movement, water quality parameters, and habitat associations of targeted fishes in river mainstem and tributary habitats.

The Homosassa project uses acoustic telemetry, electrofishing, mark-recapture, habitat assessment and abiotic measurements to investigate the increase in marine fish during winter months and their potential effects on freshwater fish. The Homosassa project will provide a comprehensive ecosystem-based approach to protect species dependent upon the health of this unique freshwater environment. Data collected during this study will assist in determining the mechanisms driving seasonal change in fish abundance in coastal spring-fed river systems. Understanding these mechanisms will assist resource managers in implementing management strategies that can protect and/or enhance critical aquatic freshwater habitat. Management implications brought forth by data collected in this study may be adapted to benefit other coastal spring-fed rivers similar in ecological nature.