harvest, but research then becomes warranted to evaluate impact 

 of this reduced exploitation on constituent stocks. Development 

 of turtle exclusion technology in fisheries incidentally 

 capturing turtles by means other than trawling is another 

 critical research need for those stocks subject to Fjjj and Fy. 

 For example, it is known that sea turtles are captured 

 incidentally in pound nets and crab pots. 



Nesting female mortality ; Research needs associated with 

 estimating fishing mortality on females at the nesting beach 

 (Fjv) , like those for Fj, are fairly well documented and the 

 approach straightforward for well studied beaches. Emphasis 

 should be placed on collecting mortality data along nesting 

 beaches that are patrolled and which have the potential for 

 controlled human access. This is particularly true in fisheries 

 like that for green turtles in Costa Rica where a permitted 

 harvest on females and males occurs on the Tortuguero nesting 

 beach (K. Bjorndal, pers. comm.). These circumstances allow 

 impact of harvest on prenesting (off the beach) and nesting 

 females (on the nesting beach) to be determined. Mortality 

 statistics must be supplemented with tag return data and 

 traditional nesting information (i.e., number of nesting females, 

 nesting frequency, nesting site fidelity, etc.) to assess better 

 the impact of Fjy and other sources of F on stock viability. 



A major research need related to Fjy estimation is 

 establishing validity of nesting and natal beach fidelity within 

 sea turtle stocks. Several workers (Richardson et al. 1978b; 

 Shoop et al. 1985) have documented this trait in loggerheads. 

 Mark and recapture research (especially the development of 

 tagging technology for hatchlings) together with aerial tracking 

 via radio receivers and observations from surface vessels are 

 needed to validate this concept and monitor any change in spatial 

 nesting patterns over time which results from human activities 

 such as fishing. 



Population Model 



Satisfying research needs for estimating fishing mortality 

 within sea turtle stocks will enable managers to develop 

 population models for conserving these endangered resources. A 

 population model that could be used for sea turtle stock 

 management has been referred to as a "gantlet" model (Paulik and 

 Greenough 1966) . This model has been employed for marine mammals 

 and can be expressed in matrix form (Vaughan and Saila 1976) for 

 segmented life histories such as those exhibited by sea turtles. 



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