Connectivity of Reef Fishes Between Mangroves and Coral Reefs in Broward County, Florida.

Many ecological and recreationally important species of marine fishes use the mangrove ecosystem for foraging, protection, spawning and as a nursery habitat. This study examined the ontogenetic migration and trophic connectivity of reef fishes in Broward County, Florida to develop a better understanding of energy flow between the local mangrove and coral reef ecosystems. Four species of reef fishes – grey snapper Lutjanus griseus, bluestriped grunt Haemulon sciurus, yellowfin mojarra Gerres cinereus, and great barracuda Sphyraena barracuda– were collected both from mangrove sites located adjacent to Port Everglades and coral reef sites located nearby offshore of Port Everglades in Broward County. All species were analyzed using 13C and 15N ratios from muscle tissues and 18O and 13C ratios from otoliths to evaluate ontogenetic migrations, foraging, and occupation within the mangrove and reef sites. Preliminary d18O and d13C otolith data indicated mangroves to be more enriched than offshore reef habitats. Food sources found in the mangroves are expected to be more enriched in 13C and 15N due to more recycling of nutrients. This study will help clarify the relative importance of the various habitats essential for early life-history stages of reef fishes