122 



Rcplilfs and Amplubians — Our Lnifii^ Rcxources 



blages in the Cayman Islands, Jamaica, and 

 Bennuda were decimated. In the United States, 

 commercial turtle fisheries once operated in 

 south Texas (Doughty 1984), Cedar Keys, 

 Florida Keys, and Mosquito Lagoon; these fish- 

 eries collapsed from overexploitation of the 

 mostly juvenile green turtle populations. Today, 

 marine turtle populations are threatened world- 

 wide and are under intense pressure in the 

 Caribbean basin and Gulf of Mexico, including 

 Cuba, Mexico, Hispaniola, the Bahamas, and 

 Nicaragua. Subadult loggerheads are captured 

 extensively in the eastern Atlantic Ocean and 

 Meditenanean Sea. Thus, marine turtles that 

 hatch or nest on U.S. beaches or migrate to U.S. 

 waters are under threats far from U.S. jurisdic- 

 tion. Marine turtles can be conserved only 

 through international efforts and cooperation. 



Information on the status and trends of 

 southeastern marine turtle populations comes 

 from a variety of sources, including old fishery 

 records, anecdotal accounts of abundance, 

 beach surveys for nests and females, and trawl 

 and aerial surveys for turtles offshore. Surveys 

 for marine turtles are particularly difficult 

 because most of their lives are spent in habitats 

 that are not easily surveyed. Hence, most status 

 and trends information comes from counting 

 females and nests. Few systematic long-term 

 (more than 10-20 years) surveys have been con- 

 ducted; the most notable are the nesting surveys 

 at Cumberland Island and adjacent barrier 

 islands in Georgia (TH. Richardson. University 

 of Georgia, unpublished data), and beaches 

 south of Melbourne in Brevard County. Florida 

 (Ehrhart et al. 1993). Beach monitoring is fairly 

 widespread in many areas of the Southeast, but 

 coverage varies considerably among beaches 

 and field crews. The only long-term sampling of 

 lagoonal or bay populations occurs at Mosquito 

 Lagoon and Chesapeake Bay, although short- 

 duration surveys have sampled Florida Bay, 

 Pamlico Sound, and Laguna Madre. Trawl sur- 

 veys of inlets and ship channels and aerial sur- 

 veys of offshore waters have been undertaken 

 periodically. 



Loggerhead and Green Turtles 



The number of turtles nesting fluctuates sub- 

 stantially from one year to the next, making 

 intei-pretation of beach counts difficult. The 

 Florida nesting populations of loggerheads and 

 green turtles appear stable based on 12 years of 

 data from east-central Florida (Ehrhail et al. 

 1993; Fig. 1). The green turtle nesting popula- 

 tion may be increasing because of protective 

 measures over the last 20 years or so. although 

 the number of nesting females is still low 

 (assuming 3-5 nests per female). North of 

 Florida, nesting loggerhead numbers are declin- 



ing 3i'7c-9% a year in Georgia and South 

 Carolina (National Research Council 1990). 

 The main cause of mortality is drowning in 

 shrimp and flsh nets (National Research 

 Council 1990). although turtle excluder devices 

 (TEDs; Fig. 2a) have helped reduce mortality 

 (Fig 2b; Henwood et al. 1992). Large juveniles 

 are most susceptible to drowning, and this is a 

 critical life stage in the population dynamics of 

 sea turtles (Crouse et al. 1987). 



Few data are available for lagoonal turtles, 

 although similar numbers have been captured in 

 Mosquito Lagoon and Chesapeake Bay from 

 one year to the next. Loggerhead and green tur- 

 tle populations, both adult and subadult. have 

 undoubtedly declined from historical levels 

 because of Iseach development and disturbance, 

 the collection of eggs, and destructive fishing 



82 83 84 85 86 87 88 89 90 91 92 93 

 Nesting season (year) 



82 83 84 85 86 87 88 89 90 91 92 93 

 Nesting season (year) 



Fig. 1 a. Loggerhead nest totals in south Brevard County, 

 Florida, 1982-93. b. Green turtle nest totals in south 

 Brevard County, Florida. 1982-93. From Ehrhart et al 

 (1993). 



