Post-Nesting Movements 



Tagging returns from turtles marked in Michoacan indicate 

 that there may be two subpopulations nesting here; one feeding in 

 the Gulf of California and adjacent waters and the other foraging 

 south off Central America. As of April 1987, of the 35 Chelonia 

 tagged in Michoacan, and recovered and reported away from the 

 nesting grounds, 2 3 were recovered from Central America: 16 from 

 El Salvador, 4 from Guatemala, 1 from Nicaragua, 1 from Costa 

 Rica, 1 from Colombia; and 12 from waters off Mexico (5 from 

 sites north of Michoacan and 7 south of Michoacan) . 



Breeding Cycles 



Considering all the remigrants detected since 1982, 54 

 (57.5%) have shown a three-year breeding cycle, 25 (26.5%) a one- 

 year cycle and 15 (16%) have shown a two-year breeding cycle. 



Clutch Size 



Clutch size of 1,935 Chelonia nests analyzed in 1986, varied 

 from 1-128 (X = 64.9) eggs. The average number of clutches laid 

 throughout the season was 2.2 (range = 1-7). The average 

 seasonal total was 152 eggs per turtle. The analysis of the 

 relation between body size and clutch size in 447 nests analyzed 

 in 1986, showed no correlation (r = 0.095). To assess possible 

 seasonal trends in clutch size, the number of eggs was reported 

 for 21 turtles that laid four known nests in 1986. A decrease in 

 the number of eggs was found as the season progressed. An 

 analysis of variance failed, however, to reveal any significant 

 differences in mean clutch size values (P>0.01). 



Renesting 



Organized into four-day groups, intervals of 11-15 days were 

 the most common (n = 2,500; 1982-1986). 



Temperature and Sex Determination 



Data from 47 nests monitored on the beach in 1984-1985 

 indicate that C. agassizii exhibits TSD. Average temperatures 

 below 27° C during the middle third of incubation resulted in 100% 

 males. Average temperature between 27.5° and 31° C resulted in 

 mixed sex ratios. Average temperatures above 31° C resulted in 

 100% females. 



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