Castaneda Alvarado, Patricia 



Nesting of the Havksbill Turtle (Eretmochelvs imbricata) 

 on the Yucatan Coast (1985-1986) 



Institute Nacional de la Pesca 

 Progresso, Yucatan, Mexico 97320 



The hawksbill turtle is an over-exploited resource. 

 Therefore, the Mexican Government has established regulations for 

 its protection. Management activities started in 1979 and, at 

 first, consisted of the collection and transplantion of eggs. 



In 1984, the Institute Nacional de la Pesca started a 

 research program to enhance the protection of these animals. The 

 program includes: collection of biological data; observation on 

 hatching success under natural conditions, as well as in 

 transplanted nests; and tagging of juveniles and adults. The 

 survey area is northeast of the Yucatan Peninsula between Rio 

 Lagartos and El Cuyo along 60 km of beaches where 14 sampling 

 sites were established. 



Methodology 



Night searches along the beach were carried out through the 

 nesting season. Searching effort was increased in June and July. 

 The beach was also covered during the morning. 



All observed turtles were measured and tagged. Egg clutches 

 were transplanted to a reserve area. The same procedure was 

 applied to all nests that were found. 



Hatchlings that emerged inside the protected area were 

 released at sunset to reduce predation. In addition, the work 

 with the juveniles was limited to measuring size and tagging. 

 Most of the results presented here were obtained in 1985 and 

 1986. 



Results 



After two years of sampling, the most frequently chosen area 

 was the middle part of the study area, from #7 to #11 sampling 

 sites. The total number of nests found was 116 in 1985 and 82 in 

 1986. 



Hawksbill turtles nest from April through September in the 

 survey area. The highest frequency of nesting females was 

 observed in May, June and the first two weeks of July. 



No significant differences in the nesting period were found 

 between the two years of observation (t = .977; p = 0.05). 



312 



