Melbourne, July 21 (IANS): In a first, the genetic mystery of why some fish are able to adjust to warming oceans has been unlocked.

Higher levels of certain stress and immune genes help fish cope with warming temperature in water over the years, the findings showed.

Researchers examined how the fish's genes responded after several generations living at higher temperatures predicted under climate change.

"Some fish have a remarkable capacity to adjust to higher water temperatures over a few generations of exposure," said Heather Veilleux from James Cook University in Queensland.

"But until now, how they do this has been a mystery," Veilleux said.

Using cutting-edge molecular methods the research team identified 53 key genes that are involved in long-term, multi-generational acclimation to higher temperatures.

"We found significantly higher levels of metabolic gene activity in fish exposed to higher temperatures for two generations, indicating that shifts in energy production are central to maintaining performance at higher temperatures," Veilleux added.

"Immune and stress genes also responded at a higher level in the second generation, indicating that increased levels of these genes are required to allow these fish to better cope in warmer water," Veilleux said.

The findings appeared in the journal Nature Climate Change.

The project involved rearing coral reef fish at different temperatures for more than four years, and then testing their metabolic performance.