Major hurricanes affect body condition of American crocodile Crocodylus acutus inhabiting Mexican Caribbean islands

Abstract

Recent models suggest that anthropogenic global warming will lead to an increase in the number of major hurricanes, which have strong effects on ecosystems and may modify animal population characteristics. The goal of this study was to assess the body condition of American crocodiles Crocodylus acutus of Cozumel and Banco Chinchorro islands, Mexico, and use it as a tool to better understand short- and long-term effects of hurricanes on crocodilian populations. Changes in body condition (Fulton’s K) of 392 crocodiles, captured between 2003 and 2015, were assessed and analyzed in response to a major hurricane through different environmental factors. Differences among populations and size classes, and between sexes, together with seasonal variation, were also evaluated. The body condition of crocodiles was generally good, with better condition for Banco Chinchorro, suggesting that these populations and the ecosystems they inhabit are healthy. Body condition for hatchlings and adults was higher than for other classes, with adults exhibiting the best condition. Body condition of Banco Chinchorro individuals varied seasonally, responding to reproductive events and environmental parameter fluctuations. We also found that C. acutus body condition is sensitive to the passage of tropical cyclones, most likely through their effects on salinity, temperature, and prey availability. Tropical cyclones have a 2fold effect on populations. In the short-term, crocodile health is negatively affected by disturbance, while the species seems to maintain and improve its body condition over the longer term. An increase in strong tropical cyclone frequency could impede the recovery of populations, while causing a continual decrease in crocodile body condition.