P-30 Characterization of West Indian manatee habitat using side-scan sonar in the Isla de la Juventud, Cuba

The West Indian manatee is divided into two subspecies, both listed as endangered. The Antillean subspecies (Trichechus manatus manatus) inhabits coastal tropical waters of Latin America and the Caribbean. Effective conservation strategies depend on understanding local habitat use, which is poorly studied in much of its range. Important habitat characteristics for manatees include availability of freshwater and vegetation, lack of strong currents, and shallow water depth. Other aspects of manatee habitat, such as benthic biotic and abiotic features, are more difficult to determine due to low water visibility. Recent studies have demonstrated that these features may be characterized using side-scan sonar. Buena Vista and San Pedro, two areas of manatee use within the Isla de la Juventud, Cuba, were characterized using side-scan sonar. The environmental complexity of both regions was measured by imaging the benthic environment and measuring water depth. Sonar images were ground-truthed visually. Additionally, freshwater sources were mapped. The number and length of creeks and channels was recorded as an indicator of the abundance of sheltered areas. Buena Vista is composed of several large, shallow lagoons, interconnected and with access to the sea by multiple channels. San Pedro is composed of two large, deeper lagoons and several smaller, very shallow lagoons. Compared to Buena Vista, San Pedro had a greater range of depth, more channels and lagoons, and access to freshwater sources. Despite the differences, both of these areas appear to be important to manatees in the region and may provide different resources (e.g. food, shelter)

Comunidades de corales en sitios de buceo del Parque Nacional Marino Punta Francés, Isla de la Juventud/ Coral’s communities on dive’s sites from Punta Frances National Marine Park, Isla de la Juventud

El objetivo de la investigación fue evaluar las comunidades de corales en sitios de buceo del Parque Nacional Marino Punta Francés. En noviembre de 2014 se establecieron cinco estaciones en el biotopo veril. Los indicadores ecológicos evaluados a nivel de comunidad fueron: diversidad de corales, composición por especies de corales, densidad de corales, esponjas y gorgonias, y cobertura del sustrato por corales, algas y esponjas. A las especies más abundantes de corales se les evaluó la salud. Para evaluar la diversidad y densidad, se empleó el método de conteo de colonias con marco de 1m2. La cobertura del sustrato se evaluó mediante el método de transepto lineal. Los índices de diversidad fueron superiores a otros estudios en este mismo arrecife. La densidad de corales (15,5 col/m2) y gorgonias (7,9 col/m2) fue elevada. La cobertura de coral vivo fue inferior al 15% mientras las algas cubrieron el 83% del sustrato. En relación a la salud, la especie más afectada por blanqueamiento, mortalidad antigua y bioerosión fue Siderastrea siderea. El 15 % de las colonias evaluadas presento mortalidad antigua. El análisis integral de los indicadores ecológicos evaluados, evidencia que el arrecife se encuentra en un estado de salud favorable y que conserva mecanismos de resiliencia aun cuando están teniendo lugar procesos negativos como los relacionados con la cobertura del sustrato. En dicho arrecife, no se encontraron evidencias de impactos relacionados con la actividad del buceo. ABSTRACT The research goal was to evaluate coral communities in the Punta Frances National Marine Park's dive sites. We surveyed five stations located at the terrace edge of this reef in November, 2014. Corals diversity, species composition, density of corals, sponges and gorgonians and substrate cover by corals, algae and sponges were the ecological indicators evaluated. Health condition was also evaluated but only in the dominant species. We assessed diversity and density by counting the number of colonies per square meter. Substrate cover was evaluated using linear transect method. Diversity indexes were higher regarding others surveys in the same reef. Coral (15,5 col/m2) and gorgonians (7,9 col/m2) densities were as well higher when comparing with other studies. Coral cover was less than 15% and algae covered the 83% of the substrate. Siderastrea siderea was the species more affected by bleaching, ancient mortality and bioerosion. Fifteen percent of the evaluated colonies had ancient mortality. The comprehensive analyzes of the ecological indicators evaluated show evidences of a favorable health state and preservation of resilience mechanisms even when some negative processes are taking place, such as those related with substrate cover. We didn't find evidences of negative impact related with diving activities in this reef