More recently, the Argos satellite has been successfully 

 used to track a leatherback turtle off the Guyanas (Fretey and 

 Bretnacher 1984) . A transmitter was attached to a nesting female 

 with a harness and provided movement information off the nesting 

 beach. This transmitter could provide valuable time series data 

 on turtle movements over large areas or throughout an entire 

 migratory cycle. 



The NMFS/SEFC has applied a smaller version of this 

 transmitter to a loggerhead turtle which towed the cylindrical 

 device (A. Kemmerer, pers. comm.). The primary drawback to this 

 system is its size, which has not been reduced to allow for use 

 with small juvenile turtles. The primary advantage of this 

 system is its longevity which could provide valuable information 

 on stock boundaries. 



Habitat studies proximal sensing ; In January 1987, the 

 Caribbean Island National Wildlife Refuges initiated an in-water 

 netting study targeting turtles off of Culebra, Puerto Rico 

 (Callazo and Boulon 1987) . Netting has been conducted during 

 seven periods from January through August and a total of 62 green 

 and four hawksbill turtles have been caught through this time. 

 An average catch of 1.2 turtles was estimated per set. Turtles 

 were tagged, weighed, measured and released. Growth rates were 

 estimated from nine recaptured turtles. It is apparent that this 

 type of study can yield information on habitat utilization and 

 "residency." The growth of turtles in the wild has yet to be 

 defined and this approach may yield important age and growth 

 information on wild turtles. 



Ehrhart (1983) has been able to compare present turtle catch 

 rates in the Indian River complex in east Florida with available 

 historical levels. His long term study has demonstrated that 

 this river system is likely a developmental habitat for juvenile 

 green and loggerhead turtles. The time series data that Ehrhart 

 (1983) is continuing to collect demonstrate how an area of high 

 turtle density can be used to index population trends. This type 

 of study is also being conducted by the NMFS/SEFC, Panama City 

 Laboratory in the Cedar Key, Florida area on the coast of the 

 Gulf of Mexico. A time series of turtle density can be used to 

 evaluate numerical trends by completing these types of netting 

 surveys in an area of relatively high and predictable turtle 

 presence. 



All three of these studies utilize gill nets for turtle 

 capture and are labor intensive. However, much information is 

 gained on turtles in localized areas from these efforts. The low 

 cost, at least compared to remote sensing studies, allows for 

 work to continue over several years. Habitats can be evaluated 

 to determine the carrying capacity of, for example, a reef or 

 grass bed for resident or transitory hawksbill or green turtles. 



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