A potential tool to mitigate the impacts of climate change to the caribbean leatherback sea turtle

Abstract

It is now well understood that climate change has the potential to dramatically affect biodiversity, with effects on spatio-temporal distribution patterns, trophic relationships and survivorship. In the marine turtles, sex is determined by incubation temperature, such that warming temperatures could lead to a higher production of female hatchlings. By measuring nest temperature, and using a model to relate the incubation temperature to sex ratio, we estimate that Caribbean Colombian leatherback sea turtles currently produce approximately 92% female hatchlings. We modelled the relationship between incubation, sand and air temperature, and under all future climate change scenarios (0.4-6.0°C warming over the next 100 years), complete feminization could occur, as soon as the next decade. However, male producing refugia exist in the periphery of smaller nests (0.7°C cooler at the bottom than at the centre), within beaches (0.3°C cooler in the vegetation line and inter-tidal zone) and between beaches (0.4°C higher on dark beaches), and these natural refugia could be assigned preferential conservation status. However, there exists a need to develop strategies that may ameliorate deleterious effects of climate-induced temperature changes in the future. We experimentally shaded clutches using screening material, and found that it was effective in reducing nest temperature, producing a higher proportion of male hatchlings, without compromising the fitness or hatching success. Artificial shade in hatcheries is a very useful and simple tool in years or periods of high environmental temperatures. Nevertheless, this is only an emergency response to the severe impacts that will eventually have to be reversed if we are to guarantee the stability of the populations.

Vegetation cover predicts temperature in nests of the hawksbill sea turtle: implications for beach management and offspring sex ratios

“…Due in large part to the endangered status of sea turtles, direct assessment of clutch sex ratios through histological examination of the gonads is not often possible, and sand temperatures are commonly used as indirect estimators of sex ratio (e.g. Oz et al 2004, Booth & Freeman 2006, Patino-Martinez et al 2012. Recent work on hawksbills has demonstrated that nest temperatures are a highly significant predictor of sex ratio in natural nests (Mrosovsky et al 2009).…”

Non-invasive monitoring of the fertilization rate in sea turtle nests: comparison between two techniques

“…Exposure to contaminants could change the production of hormones such as estradiol or vitellogenin in females affecting egg production (Rie et al, 2005), and can also alter hormone production, sperm quality and activity in males (Van Look Kime, 2003;Ferber, 2005;De Andrés et al, 2016). Moreover, the male population of sea turtles could be severely threatened by problems like male selective fishing activities and alteration of sex ratio in hatchlings due to global warming (Patino-Martinez et al, 2012;AbellaPérez et al, 2016). For instance, all sea turtle species have been classified as endangered across their range, and in spite of being an illegal practice, sea turtle meat consumption is a deeply-rooted traditional activity in most nesting areas of the world (Klemens et al, 2000;Lutz et al, 2003).…”

Multidecadal trends in the nesting phenology of Pacific and Atlantic leatherback turtles are associated with population demography

“…Instead, the conservation of leatherback turtles, especially in the Pacific Ocean where populations are already severely depleted (Spotila et al 2000, Tapilatu et al 2013, may have to rely on additional proactive measures to reduce incubation temperatures for eggs through direct manipulation of environmental conditions, e.g. watering or shading nests (Patino-Martinez et al 2012). …”