IMIS

Acoustic Study: The acoustic effects of undersea exploration and of vessel traffic are currently unknown for free-ranging sea turtles. The project will generate the first records of the acoustic environment of loggerhead sea turtles in inter-nesting habitats. Nesting females will be equipped with an acoustic bioprobe and a time-depth recorder before they swim away for an internesting interval. A recording tag will determine the acoustic environment experienced by turtles in the offshore environment. When a turtle returns to nest, the acoustic datalogger will be removed. The data gleaned and refinement of methodology developed from a nearshore study is a prerequisite before any studies are attempted on acoustic environments experienced by turtles in offshore realms. The project is a developmental step toward a more complete understanding of threats faced by sea turtles from boat traffic and opening Florida’s nearshore and offshore shelf to natural resource exploration. Clutch frequency study: In deriving population density and abundance estimates for a species, adequate sampling regimes are needed to obtain non-biased population parameters. The sampling of sea turtle populations generally occurs at rookeries for that proportion of reproductive females nesting in a given year. Acknowledged problems inherent to adequately sampling these populations include tag loss, incomplete capture-recapture records, variation in remigration schedules, variable female reproductive output, and unrecorded nesting events occurring outside the sampling area. A serious consequence of estimating female fecundity is to overestimate populations, which would be detrimental to the aims of the U. S. Loggerhead Recovery Team. To derive a more rigorous determination of clutch frequency, it is now possible to use satellite tags to evaluate how many nests a female may deposit within a season. The methods require that females be instrumented early in the nesting season and followed through the reminder of all internesting intervals until a final nest and then a post-reproductive migration. Although this is not the first time that loggerheads have been tagged in Florida nor in the Gulf of Mexico, all previous studies have generally tagged toward the end of the nesting season (July-August) and therefore would provide underestimates of annual fecundity. This study proposes to determine clutch frequency of loggerheads at a primary nesting beach for loggerheads in the Gulf of Mexico. Satellite tags as well as standard Inconel flipper tags and PIT tags will be attached to nesting female loggerheads at either Casey Key or Manasota Key during May. Females will be tracked through the remainder of the nesting season to determine clutch frequency and site fidelity. Other valuable research byproducts related to conservation will be the determination of internesting movement, exposures levels to red tide, and other risks faced during the internesting and post-nesting movements. Pilot studies in 2005 and 2006 have previously determined the feasibility and logistics of such a study but were geared to tagging later in the season. By deploying tags early in May, a more accurate determination of clutch frequency will be obtained. These results would be comparable for other beaches in Florida, but are ideally suited to beaches that also conduct simultaneous night time tag patrols, such as on Manasota and Casey.