Fem­i­ni­sa­tion of green tur­tles

Global warm­ing is the cul­prit.

Cosmos - - Digest -

One of the largest green tur­tle pop­u­la­tions in the world is at risk of ex­tinc­tion through fem­i­ni­sa­tion, ac­cord­ing to a study re­ported in Cur­rent Bi­ol­ogy.

More than 200,000 fe­males make their nests in the far north of the Great Bar­rier Reef. The tem­per­a­ture and mois­ture of the sand de­ter­mines the sex of green tur­tle hatch­lings dur­ing in­cu­ba­tion. Cooler tem­per­a­tures and wet­ter sand tend to re­sult in more males; warmer tem­per­a­tures and drier sand pro­duce more fe­males. Ris­ing tem­per­a­tures are skew­ing the ra­tio.

A sur­vey of green tur­tle num­bers has found a mas­sive sex bias in the north­ern re­gion of the reef. More than 86% of adults are fe­male, while among young tur­tles more than 99% are fe­male, says the study “En­vi­ron­men­tal warm­ing and fem­i­ni­sa­tion of one of the largest sea tur­tle pop­u­la­tions in the world”.

A sim­i­lar trend has been ob­served among sea tur­tles in Florida.

The re­searchers from the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion in Cal­i­for­nia, the Queens­land Depart­ment of En­vi­ron­ment and Her­itage, Cal­i­for­nia State Univer­sity Stanis­laus and World­wide Fund for Na­ture say their re­sults in­di­cate the green tur­tle rook­eries of the north­ern Great Bar­rier Reef have been pro­duc­ing pri­mar­ily fe­males for more than two decades, with “com­plete fem­i­ni­sa­tion” pos­si­ble in the near fu­ture.

CREDIT: GEORGETTE DOUWMA / GETTY IM­AGES

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