Tropical fish adapt to rising sea temperatures



Tropical fish adapt to rising sea temperatures Sydney: Some tropical fish, over several generations, seem to have a greater capacity to cope with rising sea temperatures. The discovery comes as a ray of hope amid concerns over the future of coral reefs and their fish in the backdrop of global warming.

The scientists wanted to know how fish would cope with the higher sea temperatures expected by 2050 and 2100, the journal Nature Climate Change reports.

"When we exposed damsel fish to water temperatures 1.5 degrees and 3 degrees Celsius above today's, there was a marked decline in their aerobic capacity as we'd expected. This affects their ability to swim fast and avoid predators," explains Jennifer Donelson, study co-author.

"However, when we bred the fish for several generations at higher temperatures, we found that the second generation offspring had almost completely adjusted to the higher temperatures," adds Donelson from ARC Centre of Excellence for Coral Reef Studies.

"We were amazed ... stunned even. It shows that some species can adjust faster than the rate of climate change," says Donelson, according to an ARC statement.

"We don't yet fully understand the mechanisms involved, but it doesn't seem to be simple Darwinian selection over a couple of generations," explains team leader Philip Munday, professor at the ARC.

"Instead, there has been a transmission of information between the generations that enables damsel fish to adjust to higher water temperatures," adds Munday.

A three degree Celsius increase in tropical ocean temperatures is predicted to occur if humanity's carbon dioxide emissions continue on their current trajectory.

IANS