Global Warming's Fish-Sex Effect

Celtkin · Aug 3, 2008

You may have missed it in biology class, but in some finned species, like the Atlantic silverside — as well as in many reptiles — sex is determined not by genetics but by temperature: the undifferentiated embryo develops testes or ovaries on the basis of whichever option conveys evolutionary advantages for that particular environment. Now, in a study published in the July 30 edition of the scientific journal Public Library of Science, Natalia Ospina-Alvarez and Francesc Piferrer have gone a little further in explaining how that mechanism works. In laboratory tests, they have demonstrated that higher water temperatures result in more male fish.

"We found that in fish that do have temperature-dependent sex determination [TSD], a rise in water temperature of just 1.5 degrees Celsius can change the male-to-female ratio from 1:1 to 3:1," says Piferrer, the study's co-author. In especially sensitive fish, a greater increase can throw the balance even more out of whack. Ospina-Alvarez and Piferrer have found that in the South American pejerrey, for example, an increase of 4 degrees Celsius can result in a population that is 98% male.
Click to expand...

Most research into fish sex determination has been done in the lab (for obvious reasons), but the pejerrey is one of the few species that scientists have been able to study in the field. And those studies have revealed that already, its proportion of males to females is skewed. "It could be because of chemical pollution or it could be because of climate change. We don't know," cautions Piferrer. "But the field data matches our predictions."
Click to expand...

http://www.time.com/time/health/article/0,8599,1827881,00.html

I am baffled by the evolutionary need for such an adaptation.

Log in / Register

Forums

Global Warming's Fish-Sex Effect

Celtkin <B>Webmaster</b> Luxury Box

Share This Page

Log in / Register

Useful Searches

Global Warming's Fish-Sex Effect

Celtkin <B>Webmaster</b> Luxury Box

Share This Page