The estimated number of nests by zone varied during the 

 season. In percent of total estimated nests from Rio Colorado to 

 Moin, the zone and subzone estimates were: 



Zone 3/17 4/17 5/12 6/13 



2 15 5 4 3 



3-4A 27 10 21 12 



4B 9 9 8 11 



5 2 4 4 2 



6 16 8 14 9 



7 4 21 16 12 



8 12 20 14 26 

 9A 10 17 12 18 

 9B 5 6 6 7 



The heaviest nesting by zone in March was along Tortuguero, 

 shifting south to Pacuare-Matina in April, more spread out in May 

 and most concentrated at Urpiano-Matino (zone 8) in June. 



TOTAL NEST ESTIMATE FOR 1987 



The total nest estimate from ground surveys at Jalova (4B) 

 was 445 and at Matina (9A) was 886. 



To obtain estimates for the entire coast from the aerial 

 surveys, factors were calculated for 1) the number of body-pits 

 counted at the Jalova and Matina subzones on 6/13 compared to the 

 number of nests known to have been laid in each section until 

 then, and 2) the number of nests estimated to have been laid from 

 6/13 to the end of the nesting season. These factors with the 

 aerial survey results for 6/13 gave an estimated total number of 

 leatherback nests during 1987 for Caribbean Costa Rica of 4,987 - 

 - rounded for discussion purposes to, 5,000 nests. 



NEST DESTRUCTION 



The preponderant cause of leatherback sea turtle nest 

 destruction along Caribbean Costa Rica is by human predators 

 (Figure 1) . Human destruction of leatherback nests along 

 Caribbean Costa Rica has been recorded as increasing since my 

 first aerial beach survey there in March 1983. This is nest 

 destruction for the alleged purpose of taking the large eggs to 

 sell in bars with the premise that eating them will increase male 

 libido. This leatherback nest destruction has been increasing 

 both in percent of nests destroyed along the entire coast and in 

 the number of nests destroyed northward into the Totuguero 

 National Park. 



Based on records obtained and familiarity with the area, I 

 estimate, conservatively, that 3,867 Deinmochelvs nests were 

 removed by man along Caribbean Costa Rica during 1987 (about 78% 

 of the total nests) . Assuming 80 fertile eggs per nest, the 



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