A project of South Carolina Marine Resources Research Institute in conjunction with the partners and sponsors detailed below.
|Name||Species||Life Stage||Release Date||Last Location||Days Transmitted|
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Adult male sea turtles play a critical role in determining the genetic diversity of sea turtle populations. Male-mediated genetic dispersal has been documented for other sea turtle species (Fitzsimmons et al. 1997) and is also presumed for loggerheads; however, little is known about the life history of male loggerheads. As juveniles, male loggerheads are much less frequently observed than females, and typically occur with a 1:3 male to female ratio (Wibbles et al. 1991; Maier et al. 2004). It is unclear whether these ratios reflect disproportionate nesting success in warmer, southern beaches where temperature-dependent sex determination would likely produce more females than males, or some other factor. As adults, male loggerheads are reported from spring trawling in the shipping entrance channels of major industrial harbors (Dickerson et al., 1995); however, despite their regular occurrence in such areas, knowledge of local habitat utilization patterns for male loggerheads on the U.S. East Coast is quite limited (Kemmerer et al. 1983; Nelson 1996; Nelson et al. 1987; NMFS 1).
Directed, in-water studies of sea turtles since the 1970’s (Kemmerer et al. 1983, Standora et al. 1993a, Botlen et al., 1994, Dickerson et al. 1995) have consistently collected adult male loggerheads in the Cape Canaveral shipping channel year-round; however, large (>90 cm SCLmin) adult male loggerheads are observed with increased abundances during April and May (Henwood 1987, Standora et al. 1993a, Dickerson et al. 1995), presumably for mating. Despite their predictable occurrence, knowledge of distributional patterns of adult male loggerheads at this location are limited to intensive (but short-term) manual tracking (Standora et al., 1993b) and monitoring (Kemmerer et al., 1983; Nelson et al., 1987) studies. A second aggregation area for adult males is also reported in Florida Bay (NMFS 1), where five adult males were tagged and released with satellite transmitters in March 2003. Only two other adult males (released in Chesapeake Bay in fall 1991, Keinath 1993) have been monitored with satellite telemetry on the U.S. East Coast.
Given the critical role that adult male sea turtles play in determining the fate of future generations, the paucity of life history data which exists for adult male loggerheads, the technology now available to both collect and instrument adult male sea turtles with devices suitable for collecting critical life history information, and a known location with high probability of collecting sexually active, adult male loggerheads, we propose to target and collect reproductively adult male loggerheads (as determined by ultrasound and laparoscopy) in the vicinity of the Cape Canaveral shipping channel during April 2006 and 2007. In addition to standard processing (blood samples for sex/genetics/health; measurements; tagging), we will outfit 9 adult male turtles with satellite transmitters to potentially document mating behavior and migratory routes to and from seasonal foraging areas. Among the questions we wish to address, the following are considered to be especially important to management of this species:
1) Can specific mating areas be identified using satellite telemetry?
2) Do males exhibit localized foraging behavior during the inter-nesting season, followed by long-distance dispersal within the summer season, as documented for nesting females monitored using satellite telemetry at numerous nesting beaches in FL, GA and SC, or do they remain near Cape Canaveral year-round as documented for several adult males tagged in Florida Bay?
3) If males disperse during the summer, do they follow the same routes and/or reach the same destinations as nesting females tagged (with satellite transmitters) on nearby Melbourne Beach (NMFS 2)?
Bolten, A.B., K.A. Bjorndal, P.J. Eliazar and L.F. Gregory. 1994. Seasonal abundance, size distribution, and blood biochemical values of loggerheads (Caretta caretta) in Port Canaveral ship channel, Florida. NOAA Technical Report Memorandum NMFS-SEFSC-353, 35 p.
Dickerson, D.D., K.J. Reine, D.A. Nelson and C.E. Dickerson, Jr. 1995. Assessment of sea turtle abundance in six South Atlantic U.S. Channels. Miscellaneous Paper EL-95-5, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.
FitzSimmons, N.N., G. Moritz, C.J. Limpus, L. Pope and R. Prince. 1997. Geographic structure of mitochondrial and nuclear gene polymorphisms in Australian green turtle populations and male-biased gene flow. Genetics 147: 1843-1854.
Keinath, J.A. 1993. Movements and behavior of wild and head-started sea turtles. Unpublished Ph.D. dissertation, School of Marine Science, College of William and Mary/Virginia Institute of Marine Science, Gloucester Point, VA, 205p.
Maier, P.P., Segars, A.L., Arendt, M.D., Whitaker, J.D., Stender, B.W., Parker, L., Vendetti, R., Owens, D.W., Quattro, J. and S.R. Murphy. 2004. Development of an Index of Sea Turtle Abundance Based Upon In-water Sampling with Trawl Gear. Final Project Report to the National Marine Fisheries Service, National Oceanographic and Atmospheric Administration Grant No. NA07FL0499, 86 p.
National Marine Fisheries Service (NMFS) 1, unpublished data. Movement tracks of five adult male and three adult female loggerhead (Caretta caretta) sea turtles tagged with satellite transmitters in Florida Bay in 2003; data available at www.cccturtle.org/sat-fl-bay03.htm
National Marine Fisheries Service (NMFS), unpublished data (2). Movement tracks of 13 adult female loggerhead (Caretta caretta) sea turtles tagged with satellite transmitters after nesting at Melbourne Beach, FL in 1998-2000 and 2002; data available at www.cccturtle.org/sat10.htm , www.cccturtle.org/sat17.htm and www.cccturtle.org/sat22.htm
Nelson, D.A. 1996. Subadult loggerhead sea turtle (Caretta caretta) behavior in St. Marys entrance channel, Georgia, USA. Unpublished Ph.D. dissertation, School of Marine Science, College of William and Mary/Virginia Institute of Marine Science, Gloucester Point, VA, 132p.
Nelson, W.R., J. Benigno and S. Burkett. 1987. Behavioral patterns of loggerhead sea turtles, Caretta caretta in the Cape Canaveral area as determined by radio monitoring and acoustic tracking, p. 31 In Witzell, W.N. (ed). Ecology of east Florida sea turtles. Proceedings of the Cape Canaveral, Florida Sea Turtle Workshop. NOAA Technical Report NMFS 53, 80 p.
Standora, E.A., M.D., Eberle, J.M. Edbauer, S.J. Morreale and A.B. Bolten. 1993a. Assessment of baseline behavior and trawling efficiency in Canaveral channel, Florida. Final contract report to U.S. Army Engineer Waterways Experiment Station, Buffalo State College, Buffalo, NY; Okeanos Ocean Research Foundation, Inc. Hampton Bays, NY, and University of Florida, Gainesville, FL.
Standora, E.A., M.D. Eberle, J.M. Edbauer, T.S. Ryder, K.L. Williams, S.J. Morreale and A.B. Bolten. 1993b. Diving behavior, daily movements, and homing of loggerhead turtles (Caretta caretta) at Cape Canaveral, Florida, March and April 1993. Final contract report to U.S. Army Engineer Waterways Experiment Station, Buffalo State College, Buffalo, NY; Okeanos Ocean Research Foundation, Inc. Hampton Bays, NY, and University of Florida, Gainesville, FL.
Wibbles, T., Martin, R.E., Owens, D.W., and M.S. Amoss. 1991. Female-biased sex ratio of immature sea turtles inhabiting the Atlantic coastal waters of Florida. Can. J. Zoology, 69: 2973-2977.