IDENTIFICATION OF SEX IN HATCHLING LOGGERHEAD TURTLES (CARETTA-CARETTA) BY ANALYSIS OF STEROID CONCENTRATIONS IN CHORIOALLANTOIC AMNIOTIC FLUID/

A major difficulty in sea turtle conservation is the inability to nonl ethally and noninvasively identify the sex of hatchling sea turtles. T raditional sexing techniques such as plasma sex steroid quantification cannot he applied to hatchlings without sacrificing the hatchlings or utilizing invasive procedures. This paper presents a technique for se xing hatchling sea turtles by analysis of sex steroid concentrations i n egg chorioallantoic/amniotic fluid (CAF). Metabolites of estradiol-1 7 beta (E) and testosterone (T) in CAF are best expressed as an index or E:T ratio. Chorioallantoic/amniotic fluid E:T ratios for males (0.5 +/- 0.1) were significantly lower than these for females (2.2 +/- 0.3 ). Then separated by utilizing an E:T ratio of 1.25 as the determinant index value, 27 of 28 hatchlings were designated correctly as males ( E:T <1.25) or females (E:T greater than or equal to 1.25). Sex was ver ified for all hatchlings by gonadal histology. This study shows signif icant concentrations of T and E metabolites in CAF and plasma of hatch ling loggerhead turtles and illustrates the use of a nonlethal, noninv asive method for determining sex, which could be potentially utilized for other endangered reptile and avian species. (C) 1995 Academic Pres s, Inc.