Reproduction and Migrations of the Ascension Island Green Turtle (Chelonia mydas)

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Abstract
Data on the reproductive ecology and migrations of the genetically isolated colony of the green turtle, Chelonia mydas, at Ascension Island-which has been studied intermittently between 1960 and 1976, and intensely in 1977 and 1978-are compiled. Within a season, turtles lay successive egg clutches at a mean interval of 13.9 d. Because the female turtles have difficulty constructing egg chambers in the coarse, dry Ascension sand, they usually dig multiple trial nest holes, often on more than one night, before depositing eggs. The coincidence of the Ascension nesting season with the period of heaviest precipitation may be a response to dry beach conditions at other times of the year. Females may lay as many as seven clutches in a season; the average number recorded was 3.0, which may underestimate the true figure. The sizes of egg clutches laid early in a season by an individual female tend to be higher than those laid later in the season; the average clutch size was 120.9 eggs. The predominant remigratory intervals recorded in Ascension turtles, which appear to come exclusively from the coast of Brazil, (N = 69) are 4 yr, followed by 3 yr. Recorded tag-loss in remigrant turtles was 78%. Long distance tag recoveries of 66 turtles tagged at Ascension were made off the coast of Brazil, 2300 km to the east, between latitudes 3.degree. and 22.degree. S. The longest time interval between the tagging of a turtle at Ascension and its recovery in Brazil was 6 yr. The shortest Brazilian recovery time was 56 d after the turtle had last been observed nesting at Ascension. An estimated 1980-3590 females nested at Ascension during the 1976-77 season, and 1320-2390 during the 1977-78 season.

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