SEA TURTLE FACTS
In general, turtle hatchlings emerge from their nest at night, and spend their early life stages in the open ocean feeding on planktonic food (Carr, 1986). After this pelagic stage, juveniles undergo a behavioral shift and migrate to coastal waters to forage (Carr & Caldwell, 1956). Each species of sea turtle targets different prey, ranging from seagrass to crustaceans and mollusks to jellyfish. Upon maturity, estimated between 20-50 years and varying by species (Goshe et al., 2010), they will migrate back to their natal beaches to mate and nest.
A few weeks after mating, adult female turtles crawl onto their natal beach at night and take at least two hours to dig their nest pit. The number of eggs in a nest, called a clutch, varies by species and ranges from 50-200 eggs. An individual female lays between 2-8 clutches per nesting season, and she will nest every 2-4 years (Esteban et al., 2017)
Turtle populations demonstrate many life history traits that make them vulnerable to environmental change and anthropogenic impacts. These characteristics include a long pelagic maturation period, late sexual maturity, large clutch sizes with high juvenile mortality, and long migrations between nesting and feeding locations (Van Buskirk & Crowder, 1994). Thus, nearly all species of marine turtles are included in the International Union on the Conservation of Nature’s Red List of Endangered Species (IUCN, 2018) and are protected by Appendix I of the Convention on the International Trade of Endangered Species (i.e., no international trade is permitted) (CITES, 2018). Despite this protection, illegal sea turtle fisheries continue to operate in many countries.
Temperature Dependent Sex
The incubation temperature of a nest determines the gender of a hatchling. For marine turtles, eggs incubated at ~29°C produce a 50:50 sex ratio, called the pivotal temperature (PT), but this differs slightly between species and geographic location. Temperatures above the PT produce greater proportions of females, while temperatures below the PT result in more male hatchlings in the clutch (Mrosovsky, 1994). Scientists thus predict that elevated temperatures associated with global climate change will increasingly skew sea turtle sex ratios towards females.
While all countries (Egypt, Eritrea, Israel, Jordan, Saudi Arabia, Sudan and Yemen) surrounding the Red Sea legally protect marine turtles through national laws and international agreements, enforcement both at sea and around nesting sites is severely lacking (Mancini et al. 2015). As a whole, the Red Sea is an understudied region of the world, and this is especially true regarding sea turtle research. Decades of political unrest have prevented turtle surveys in Somalia, Eritrea, Sudan and Yemen, and so the status of sea turtles in these areas are unknown (Mortimer & Donnelly 2007). The limited data available suggests that around 1,500 female turtles nest annually throughout the Red Sea (Hanafy 2012).