Abstract
Coastal rivers provide habitat for fishes that have developed life-history strategies to take advantage of low salinity and high structural complexity. The coastal rivers of southeastern Florida have been ranked high for restoration at a national scale by conservationists because of the great potential for projects to benefit both human assets and aquatic communities. To help prioritize projects, a fisheries-independent monitoring dataset was analyzed to identify fish habitat using hotspot analysis and habitat suitability. An initial examination testing for broad seasonal changes (high vs. low freshwater inflow) in species distributions showed little change; thus, we concluded that static habitat (e.g., geomorphological features, shore types) was important for supporting fishes in this system. A river section, North Fork St. Lucie River, located 23-45 km from the river mouth and comprised of braided river channels and mangrove backwaters was a hotspot for economically important species such as common snook and red drum. The same river stretch supported a suite of regionally unique tropical species including opossum pipefish, smallscale fat snook, and bigmouth sleeper that had affinities for low salinity. Species were partitioned within this river stretch by salinity, depth, and shore type (e.g., smallscale fat snook compared to common snook used shorelines that were fresher, deeper, and had fewer mangroves). Restoration efforts can be prioritized by (1) maintaining low salinity (< 15) and reconnecting floodplains and riverine backwaters in the North Fork St. Lucie River, an area comprised of fish hotspots, and (2) exploring strategies to improve fish habitat in other areas currently less used.