engleski

Sex ratios of juvenile loggerhead sea turtles, Caretta caretta, in the Mediterranean

We examined the sex ratios of 100 juvenile loggerhead turtles with CCLn-t ranging from 24.0-69.0 cm (mean: 41.8 ; SD: 10.2) from the central and eastern Mediterranean by histological analysis of gonads. The tissue samples were fixed in 10% formalin for minimum of 48 h, dehydrated through graded series of alcohols, embedded in paraffin, and sectioned at 8 μ m. Sections were stained with hematoxylin and eosin, and examined with a light microscope. Based on the carapace length, we divided loggerheads into three size classes: pelagic juveniles (CCLn-t < 30.0 cm), post-pelagic juveniles (30.0 - 49.9 cm) and benthic juveniles (50.0 – 69.9 cm), and tested a difference in the sex ratios between the groups. The sex ratios are given as a male/female ratio. The overall sex ratio is equal to 1.00. In pelagic juveniles, the sex ratio showed strong male bias (2.00), but it could be explained by the small sample size (N = 9). In both, post-pelagic and benthic juveniles we have found no significant aberration from a 1:1 ratio (0.92, N = 69, and 1.0, N = 22, respectively). No difference was also found between the sex ratio in central and eastern Mediterranean ; in both regions it equals to 1.00 (N = 42 and 58, respectively). Our results are surprising, considering the predicted female skewed hatchling production on the Mediterranean nesting beaches. Several hypothesis to such results are proposed.

sea turtles; sex ratios; Mediterranean; conservation

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