Thaindian News

Washington, Feb 14 (IANS) Fish which adapted to the polar condition with ‘anti-freeze’ proteins, tens of millions of years ago, are now being endangered by a rapid rise in ocean temperatures.

“A rise of two degrees centigrade temperature of water will likely have a devastating impact on Antarctic fish lineage, which is so well adapted to water at freezing temperatures,” said Thomas Near, associate professor of ecology and evolutionary biology at Yale University, who led the study.

The successful origin and diversification into 100 species of fish, collectively called notothenioids, is a textbook case of how evolution operates, the journal Proceedings of the National Academy of Sciences reports.

A period of rapid cooling led to mass extinction of fish acclimated to a warmer Southern Ocean. The acquisition of so-called antifreeze glycoproteins enabled notothenioids to survive in seas with frigid temperatures, according to an Yale statement.

This evolutionary success story is threatened by climate change that has made the Southern Ocean around Antarctica one of the fastest-warming regions on the Earth. The same traits that enabled the fish to survive and thrive on a cooling Earth make them particularly susceptible to a warming one, notes Near.

Notothenioids account for the bulk of the fish diversity and are a major food source for larger predators, including penguins, toothed whales, and seals. Peabody Museum of Natural History has one of the most important collections of these specimens in the world.