Hutchinson Island

Hutchinson Island Near-shore Reef Sea Turtle Census

In Florida, Atlantic near-shore reef habitats have recently been recognized as potentially very important developmental habitats for marine turtles, particularly the green turtle (Chelonia mydas).  These habitats are typically found in high energy surf zones and have received very limited research attention compared to other protected sites where sea turtles are found.

In 2003, the Florida Wildlife Research Institute (FWRI) received funds from the National Marine Fisheries Service to investigate the abundance and distribution of marine turtles in these near-shore hard-bottom habitats.  Inwater Research Group was asked by FWRI to develop and conduct a study that would determine species composition, relative abundance and distribution of marine turtles found at these sites.  A repetitive visual transect method was developed by our group and was implemented in 2004 and 2005 covering all seasons of the year.  These sea turtle abundance surveys were conducted in the area just offshore of St. Lucie and Martin Counties in east central Florida.

The area selected for surveys extends from 4 km north of Ft. Pierce Inlet (offshore of North Hutchinson Island) to 6 km south of St. Lucie Inlet (offshore of Jupiter Island), a distance of approximately 48km. Within this overall study area, six specific transect locations were established, containing a total of eight permanently established transects.

Each transect was exactly 3 kilometers long and oriented parallel to the beach. Transect locations were selected based on analysis of aerial photography that clearly showed areas of hard-bottom habitat.  Four of the eight transects were designated as inshore transects, located within 200m of the beach and the remaining four transects were designated as offshore transects, located at least 400 meters off the beach. The establishment of both inshore and offshore transects allows for an analysis of cross-shore differences in turtle abundance levels.

Sightings of marine turtles along these transects were recorded by GPS and maps of cumulative data collected at each transect area were generated.  For more details about this project please see our summary reports page.