99% female: Climate change likely behind Green sea turtles’ skewed sex ratio

Why it is in news?

  • One of the world’s largest turtle populations is turning almost entirely female, and the cause is most likely warming temperatures in a changing climate.
  • The sex of hatchlings in sea turtles and in a few other species such as alligators and crocodiles depends on the temperature of the sand in which the eggs incubate, with warmer temperatures resulting in female hatchlings and cooler temperatures in males.
  • The US National Oceanic and Atmospheric Administration (NOAA) website specifies the temperature ranges that lead to offspring of one sex or the other: male when it is 27.7°C or cooler, female when 31°C or warmer, and a mix of male and female baby turtles when the temperature fluctuates between these two limits.
  • Turtles of the northern Great Barrier Reef (GBR) are genetically different from those of the southern GBR.
  • The results of the study, published in Current Biology, showed an alarming female bias in turtles from the northern Great Barrier Reef, which is warmer than the southern GBR: 86.8% female among adults, 99.8% female among subadults and 99.1% female among juveniles. A female bias showed again in turtles from the cooler, southern GBR, but this was less stark: between 65% and 69%

Climate change link

 

Green sea turle

  • The green sea turtle  also known as the green turtle, black (sea) turtle or Pacific green turtle, is a large sea turtle of the family Cheloniidae.
  • Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean.
  • [The common name comes from the usually green fat found beneath its carapace; these turtles' shells are olive to black
  • It is listed as endangered by the IUCN and CITES and is protected from exploitation in most countries.

Source

Indian Express

Posted by Jawwad Kazi on 15th Jan 2018