Climate change turning turtle populations female

| 09/01/2018 | 44 Comments

(CNS): Marine scientists are sounding the alarm over a new threat to the endangered green sea turtle, following research by experts on a population of the animals around the Great Barrier Reef. The results of the study, which has been published in the scientific journal, Current Biology, found “extremely female-biased sex ratios in an important sea turtle population” because of the increased temperature of the beaches where they are nesting. The authors said turtle hatchlings from warmer beaches around the Great Barrier Reef were massively biased towards females. 

The National Oceanic and Atmospheric Administration (NOAA) in partnership with Australian researchers studied hundreds of turtles and found that 99% of turtle hatchlings from warmer beaches in the northern GBR are now female.

“The impacts of rising temperature are particularly pertinent in species with temperature-dependent sex determination (TSD), where the sex of an individual is determined by incubation temperature during embryonic development,” the researchers explained. “In sea turtles, the proportion of female hatchlings increases with the incubation temperature. With average global temperature predicted to increase 2.6°C by 2100 many sea turtle populations are in danger of high egg mortality and female-only offspring production.”

Using genetic markers and other techniques for the first time, the marine biologists were able to link male and female green turtles foraging in the Great Barrier Reef (GBR) to the nesting beach from which they hatched. While there was a moderate female sex bias of 65%–69% in turtles originating from the cooler nesting beaches in the south, turtles originating from warmer northern beaches were extremely female-biased. 99.1% of juveniles, 99.8% of sub-adult and 86.8% of adult-sized turtles were all female.

This data shows that the northern GBR green turtles have been producing primarily females for more than two decades, the scientists said, warning that this could signal a complete feminization of the population in the near future.

Where turtles are greatly endangered they tend to produce a lot more female offspring, which is nature’s way of boosting reproduction numbers, but the researchers on this study pointed out that the turtle population in the GBR area is one of the largest in the world, which should lead to a balance between the sexes. The scientists believe that climate change is distorting the natural balance.

Conservation groups are raising concerns, and the Australian branch of the World Wildlife Fund pointed out the obvious threat the loss of male turtles will be to the future of one of the most important turtle populations in the world.

Meanwhile, the instability of the planet’s climate, which is contributing to the bitterly cold weather in the US, has had a different but detrimental impact on sea turtle populations in the Atlantic. Volunteers and with Fish and Wildlife wardens released hundreds of turtles back into the sea that had washed ashore recently, “cold stunned”, far too chilled to swim, because of the massive fall in sea temperatures in some bays around the state, according to local reports.

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Category: Marine Environment, Science & Nature

Comments (44)

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  1. Anonymous says:

    If you want to save turtles, eat turtles. Someone will make sure there are plenty of them.

  2. Diogenes says:

    Don’t let Alex Jones catch wind of this,
    The Alt-right would invade to save the male turtles from being transgenderfied against their will

    Then again the Alt-Right would feel right at home in Cayman

  3. Phlexx says:

    Isn’t that a good thing though ? When you really think about it….The more females there are the better off they would be. Then the animal wouldn’t be endangered. Just save a few males for breeding.

    They wouldn’t even have to pay child support.

  4. Anon says:

    And we’re goin’ to Surf City, ’cause it’s two to one
    You know we’re goin’ to Surf City, gonna have some fun
    You know we’re goin’ to Surf City, ’cause it’s two to one
    You know we’re goin’ to Surf City, gonna have some fun, now
    Two girls for every boy!

    Surf City- the Beach Boys

  5. Anon says:

    More “The sky is falling” bs. Turtles have endured bigger temperature variations in the past. How do we know? Easy – we know that there have been numerous large temperature fluctuations over the last couple hundred million years. Turtles have been around for the last couple hundred million years. And they are still here. QED.

  6. Anonymous says:

    I repeat my comment, but will start from the last sentence : ” this is really bad news for modern day marine life.”
    “250 million years ago oxygen levels on earth = 35 percent. In 1850, oxygen levels = 22 percent. Today’s levels now hover around 19 percent or less in most westernized cities. This assumes, of course, these cities are at sea level. O2 levels required for healthy humans = 19.5 percent. This proof is found on an oxygen dissociation curves of hemoglobin. This is not a good development for our mitochondria. But this is really bad news for modern day marine life.”
    “Since 1950, we have lost 90 percent of the fish in our seas. No one seems to notice this. It appears nature is now batting last, in the human line up of priorities. This is when the world’s vertical circulation current, from shallow to deep in the sea, and vice versa, shuts down. It becomes important because that’s how oxygen is sent down to the ocean depths via (higher density water) the water column and important marine food sent up via the thermohaline current. This effect is will be felt differently in different places on the earth. This will be felt strongest at the mid-latitudes between the Tropic of Cancer and Capricorn. As it happens, the water there will become more blue as life dies in the ocean. The reason is simple physics. When sea water temperatures rise, oxygen diffuses out of it as we mentioned earlier. Hotter ocean water becomes “less electron dense” and colder water allows more oxygen to become dissolved within it. When there is less electron density in water, the sun’s visible light can not liberate all the electrons to make the maximum amount of energy possible. Electrons give chemicals their specific chemical phenotype in chemistry. It seems many biochemists may have forgotten that very basic natural truth too, when we speak about foods. When electron density goes down in chemistry, life also begins to simplify because of a lack of energy to split electrons from water. This limits life ability to survive. This is why water chemistry matters huge to life and to the marine food chain.”

    • Hancock says:

      Presumably if we put female turtles in freezing water we can convert them to males

      • Anonymous says:

        And that comment just illustrates perfectly the dumbasses that frequent these islands.
        Just so you’re clear, it’s during the incubation stage that gender is formed.

    • Really? says:

      How do you lnow the oxgen level 250 millions years ago. What did they measure the oxygen level with in the 18 century with?

      • Anonymous says:

        Well, the scientists used this thing called science. They work out indicators of oxygen levels and then find them and use them to work out the oxygen levels. Any seven year old with a science encyclopedia knows that. But that is beyond you.

      • Anonymous says:

        Ice core samples. The polar ice is millions of years old. They take samples there and analyze it.

  7. Anonymous says:

    Wish we’d get some cold stunning temperatures here as this would be a great opportunity for all inhabitants of Cayman to collect and dispatch the scourge of green iguanas.

  8. Anonymous says:

    How about expanding the Turtle Center idea? They use a temperature control room. Oh I forgot the environmentalists are against it. They think they can control the world’s poor with “It’s against the Law”. Let me tell you that not even in Communist Cuba. They have not stopped poor people from eating anything against the law. In Cuba you go to jail 20 years for every pound of meat you kill for food. So promote Turtle Centers around the world like they do any other farm.

  9. Anonymous says:

    Sadly, for many the issue thrown up by the research is “ but do female turtles taste better”?

  10. Anonymous says:

    All this sounds like liberals trying to find a way to close the Cayman Turtle Farm. Al Gore fanatics.

  11. Al Catraz says:

    They should be allowed to marry.

  12. Anonymous says:

    We might live in the “goldilocks’ zone, but that doesn’t mean we can’t become desolate and barren like the other planets in our system, thanks to global warming.

  13. Anonymous says:

    Build shades over the nests.

  14. Anonymous says:

    Dear CNS,

    I want to invite you to my local, grassroots church where my (during childhood) old-school pastor still leads his ageing but loyal congregation.

    His infallible biblical interpretations and regurgitations read IDENTICAL to your offerings as it concerns AGW “climate change”.

    Very odd, and interesting.

  15. Anonymous says:

    Good time to be a male turtle… just not in Cayman’s waters as you would likely end up poached and in a pot.

  16. West bay Premier says:

    These Climate change scientist are trying to see if anything and everything would stick to the wall even calling turtles animals . Did these Scientists find that cooler beaches produced more male reptile turtles ? Or did they find that cooler beaches produced more animal turtles .

    • Anonymous says:

      Climate change denial is racist and sexist, and the leading cause of erectile dysfunction. 98% if scientists agree.

    • Anonymous says:

      If turtles aren’t animals, what the hell are they?

    • Anonymous says:

      You uneducated fool, clearly a reptile is an animal.

      plural noun: reptiles
      a vertebrate animal of a class that includes snakes, lizards, crocodiles, turtles, and tortoises. They are distinguished by having a dry scaly skin and typically laying soft-shelled eggs on land.
      synonyms: reptilian, snake, serpent;

      • West bay Premier says:

        Anonymous 11:32 pm , A vertebrate “species ” not animal, the rest of your definition is correct.

        • Anonymous says:

          The quote above comes direct from the Oxford English Dictionary. Note the word ANIMAL.
          The word Animal is a noun and adjective. The noun as defined in science is a living organism that feeds on organic matter, typically having specialised sense organs and nervous system and able to respond rapidly to stimuli. Example: Turtle or any other reptile.
          The adjective is termed to relate to or is characteristic of animals.

          But that probably goes over the head of a reptile munching idiot that doesn’t understand or cant be bothered to read facts instead of inventing them through ignorance.

          No wonder that cruelty against turtles is so pernicious on Cayman, they’re not even covered by the Animals Law because of the backwards nature of your reasoning. In effect, whilst it is illegal to capture or kill a wild turtle, there are no laws to stop cruelty or harassment. If there were the Turtle Centre would close overnight.

          Get it right, a turtle is an animal and should not be treated any differently from any other protected species.

          • Anonymous says:

            6:19 pm you alleged that “there are no laws to stop cruelty or harassment. If there were the Turtle Centre would close overnight.” Really? 1). What is your evidence that “there are no laws to stop cruelty or harassment” of sea turtles? 2). And what is your evidence that if there are such laws, “the Turtle Centre would close overnight”? Or are you just regurgitating the deliberately ignorant rants of a so-called “animal welfare” organization that uses sea turtles as the front cover for its fund-raising appeals to get well-meaning people to give them more money?

            • Anonymous says:

              Quote the section of the Animals Law or the NCL that specifically covers cruelty to sea turtles, then try again.
              I note you’re not continuing your mind numbingly stupid argument re: definition of an animal/reptile, or are you another dummy that can’t read?

              • Anonymous says:

                Don’t worry WBP or 4:53am, I’ve done it for you.

                PART I – Introductory
                1. This Law may be cited as the Animals Law (2013 Revision).
                2. In this Law-
                “animal” includes live mammals, reptiles (other than marine turtles), amphibians, birds, fish, invertibrates and insects;

                So you see genius, specifically marine turtles DO NOT have protection under cruelty law as they are not deemed to be an animal by this backwards country, even though science and the OED clearly state that they are. That is an omission of convenience as inclusion would definitely leave the TC and anyone who deliberately sought to cause distress or damage to marine turtles open to cruelty laws, as they would in any 1st world country with a conscience.
                Therefore any cruelty that does take place at the TC, including over crowding, confinement of a wild animal and human handling of such etc…. isn’t illegal under the law, including the NCL.

                But don’t let the facts get in the way of ignorance.

        • Anonymous says:

          WbP, you have a computer, and internet access. Go educate yourself on the definition of “animal”. I suspect you are confusing the word with “mammal”.

      • Anonymous says:

        Reading CNS is quite hilarious this morning!, first an in depth study in maths on how to calculate the square miles of Cayman and now a scientific study on animals/ reptiles. Only in our beloved isle. Keep it up we all can learn something daily.

    • Anonymous says:

      Climate change is happening whether you believe humans are assisting it or not, if you don’t believe that then you don’t believe there was an ice age 12,000 years ago.

      This article is highlighting one effect of that change, just like rising sea levels is another change. Doing nothing, but whining that humans aren’t responsible is like not preparing for a hurricane because you don’t think humans caused it

      Its just dumb

    • Jack Meoph says:

      Yeah, you tell ’em bredren. Everybody knows turtles are plants!

  17. Anonymous says:

    Playing the sea turtle card is racist.


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