Preliminary study on morphological and microbial profiles of loggerhead turtle (Caretta caretta) eggs in nests with compromised viabilityin western Sicily (Italy,Mediterranean Sea)

Abstract

This study presents an integrated analysis of morphobiometric and microbiological parameters of unhatched eggs of Caretta caretta collected from nesting sites along the west coast of Sicily. Eighteen nests in four provinces (Trapani, Palermo, Agrigento, and Caltanissetta) were examined, revealing marked variability in hatching success, ranging from 0% to over 90%. Statistical analysis showed a significant correlation (p < 0.0001) between the total number of eggs laid and the number of hatched and unhatched eggs, although a direct relationship with hatching success rate was not observed. Microbiological analyses revealed the recurring presence of potentially pathogenic bacteria, such as Aeromonas hydrophila, Yersinia enterocolitica, Pseudomonas aeruginosa, Pseudomonas stutzeri, Escherichia coli, Bacillus cereus, Serratia marcescens, and Vibrio alginolyticus, with a particularly high incidence in nests with low or no hatching rates. These results highlight the potential impact of microbial contamination on embryo viability and underscore the role of local environmental conditions in modulating reproductive performance. The study provides an initial framework for assessing biotic and abiotic stressors affecting sea turtle nests in the western Mediterranean, a region that has yet to be studied extensively in this regard.