As a sea turtle develops in an egg, their gender when hatched is determined after fertilization, due to its environment. The heated temperature of the sand that is incubating the egg determines the sex of the sea turtle as it develops. In recent studies, scientists have found warmer temperatures correlate to eggs hatching as majority female, while slightly less warm temperatures related to a more even ratio of sexes.
The world has been getting warmer and warmer due to climate change. Ice caps are melting, winters are colder, and beaches are getting hotter – especially in the summer. Due to this rise in temperature, sea turtle eggs are hatching as predominantly female.
Scientists are finding, in the Pacific Ocean – the world’s most significant and largest green sea turtle rookery – that female green sea turtles are now outnumbering male sea turtles 116:1. That is 99% of the hatchlings developing as female.
The National Oceanic and Atmospheric Administration in Hawaii claims that this is an “extreme” repercussion of global warming. “We are talking a handful of males to hundreds and hundreds of females,” said a representative of the administration. This finding left many involved in the study in shock.
Supervisor of ecotoxicology and risk assessment laboratory at Florida International University, Tiffany Yanez, says that “climate change is creating immense risk for conditions of wildlife biology.” When asked the implications of this occurrence, Yanez stated, “Having studied the behavior of marine animals, I can hypothesize that if turtles are continuously laying eggs that only become females, this could change the entire behavior of the species. This could not only affect how females interact with each other, but with other marine species as well. Females could become more aggressive towards each other for the sole purpose of procreating and increasing their fitness. As we know, turtle populations are declining, and the decrease in males could add to this crisis, possibly having an effect on the trophic webs.”
Sea turtles already face threats of ocean pollution, bycatch, and other direct human implications, making all sea turtles either endangered or threatened. All 7 species of sea turtles -greens, loggerheads, leatherbacks, hawksbills, flatbacks, olive and Kemp’s ridleys- are extremely vulnerable to climate change and all are susceptible to this same ramification.
More work must be done to assess sex ratio changes of sea turtles in various parts of the world, however, scientists predict that as temperatures keep rising the same effect will occur in other beaches globally. It is expected that with a rise of just a couple degrees Celsius that nests will become solely female producing, eventually diminishing whole populations of sea turtles.
It is clear that the public needs to become more aware of the consequences of rapidly increasing temperatures in the environment. Efforts must be taken to help conserve marine species in our oceans if we expect them to survive through future generations.