Acoustic Telemetry used to track red snapper, gag grouper, red grouper, and scamp grouper in particular areas of Gray's Reef National Marine Sanctuary

NOAA's Gray's Reef National Marine Sanctuary, located 17.5 nautical miles off Sapelo Island, GA, is one of 14 marine protected areas that make up the National Marine Sanctuary System and one of the largest near shore live-bottom reefs in the southeastern United States. The reef attracts numerous species of benthic and pelagic fish, including black sea bass, snapper, grouper, and mackerel that are tracked using acoustic tags and receiver arrays. The purpose of this research is to determine the residence time of the fish in the reef, the preferred habitat, and how these options may change with time. There are sixteen fish tagged and tracked in Gray's Reef National Marine Sanctuary: 3 red snapper Lutjanus campechanus, 7 scamp grouper Mycteroperca phenax, 5 gag grouper Mycteroperca microlepis, and 1 red grouper Epinephelus morio. Ten acoustic receiver arrays are deployed in the sanctuary that are able to detect tags over a 200 m radius reliably and a 300 m radius 50% of the time. In order to better monitor the protected area, this project seeks to 1) create a map of the locations of the receivers to determine the amount of area covered and the amount of overlap between receivers; and 2) determine the positions of the receivers and relate them to the bottom topography of Gray's Reef. The bottom topography currently mapped in the reef was done by side scan sonar and multibeam mapping. Kendall et al. (2005) determined that Gray's Reef contained 4 different habitats: densely colonized livebottom, sparsely colonized livebottom, rippled sand, and flat sand. The percentage of each habitat type in a receiver detection range is also needed to compare between the habitats of the receivers. This poster presents the preliminary data from the first year of this project.