Alvarado, Javier and Alfredo Figueroa 



The East Pacific Chelonia Population of Mlchoacan. Mexico; 

 Status. Post-Nesting Movements, and Aspects of Reproductive 



Biology. 



Escuela de Biologia, Universidad de Michoacan, 

 Morelia, 5800, Michoacan, Mexico 



The beaches of Colola and Maruata on the Michoacan coast are 

 the only remaining important nesting sites of the endangered 

 black turtle ( Chelonia agassizii ) in North America. Because of 

 heavy exploitation for meat and eggs, a drastic decline in 

 numbers has occurred in the last decade. Since 1982, the Escuela 

 de Biologia of the Universidad de Michoacan has been carrying out 

 a field conservation-research program (financed mainly by World 

 Wildlife Fund-US and U.S. Fish and Wildlife Service) on behalf of 

 the black turtle. In this paper a summary of the results of the 

 project from the previous five years is presented. 



Conservation 



Through relocation of nests to protected hatcheries 

 approximately 900,000 sea turtle hatchlings (80% Chelonia) have 

 been released into the East Pacific. Although the poaching rate 

 of adult turtles has been lowered, illegal hunting and incidental 

 capture remain the most serious threats to the recovery of 

 Chelonia in the East Pacific. 



Nesting season 



Although females nest year round in Michoacan, most of the 

 nesting occurs from September through December with the peak in 

 October and November. 



Trends in Nesting Numbers 



The maximum number of recorded nesting females was 4,483 in 

 1982. In 1983 the estimate was 1,000 nesting females. In the 

 1984 season, 940 females were estimated. In the 1985 season 

 1,200 females were estimated. In 1986, 3,334 females was the 

 number calculated. The decline in 1983, 1984 and 1985 could be 

 ascribed to El Nino which swept through the Pacific in 1983, 

 perhaps disrupting the food-chains in some of the main chelonian 

 foraging grounds in Central America. 



Although the overriding trend is of a drastic long-term 

 decline (in 1970 about 25,000 females nested in Michoacan) the 

 slight recovery shown in 1986 is encouraging. 



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