Influences of the Local Climate on Loggerhead Sea Turtle (Caretta caretta) Hatchling Output

LLocal climate influences sea turtle hatching and emergence success with climatic extremes affecting embryonic development and hatchling emergence. Thus, it is crucial to understand how different climatic variables affect hatchling output presently and explore how potential climate change may impact future hatchling output and population stability. This thesis examines the influences of six climatic variables (air and sea surface temperature, precipitation, humidity, wind speed, and solar radiation) on the hatchling output of the loggerhead sea turtle (Caretta caretta) for two distinct nesting populations: Southwest Atlantic Loggerhead Regional Management Unit, which nests in Brazil, and the Northern Gulf of Mexico Loggerhead Recovery Unit, which nest in North Florida, USA and is part of the Northwest Atlantic Loggerhead Recovery Management Unit. Additionally, this thesis explores how potential climate change may impact future hatchling output. The main drivers of hatchling output varied across populations, nesting regions, and beaches. In Brazil, air temperature and precipitation were found to be the main climatic drivers of hatchling output, whereas in North Florida as well as air temperature and precipitation, humidity was a significant climatic driver of hatchling output. Climate projections show air temperatures warming at all sites throughout the 21st century, while projections for precipitation and humidity varied regionally. Our projections indicate that by 2100, tropical nesting beaches (Bahia, Brazil) will experience declines in hatching success, while temperate regions (Espirito Santo and Rio de Janeiro, Brazil and North Florida) will experience increases in hatching success. This thesis highlights the need to assess the climatic drivers of hatchling output at a regional scale, especially in temperate areas, to better understand how projected climate change may impact populations and better inform management.