Warmer waters can kill fish species
Mon, 18 Apr 2011 18:08:17 GMT
A new study shows that climate change and warmer sea waters gravely threaten some fish species and will eventually result in their death in some parts of the world.
According to the study published in the journal Nature Climate Change warmer temperatures will stop the growth of some fish species, increase their stress and raise their risk of death.
A team of Australian scientists used long-term and current data to study long-lived fish species called the banded morwong in the Tasman Sea, between Australia and New Zealand and the effects of global warming on their longevity.
Studies showed that the morwong's growth in some areas has been slowed by an increase in sea surface temperatures of nearly 2 degrees Celsius over the past 60 years in the Tasman Sea, which is one of the most rapid increases in the southern hemisphere's oceans.
According to marine ecologist Ron Thresher of Australia's state-backed research body the CSIRO, warming conditions generally boost growth rates in cold-blooded animals, but there is a limit.
"By examining growth across a range that species inhabit, we found evidence of both slowing growth and increased physiological stress as higher temperatures impose a higher metabolic cost on fish at the warm edge of the range," Thresher told Reuters.
"A lot of commercial fish don't move very much," he added saying “They tend to return to the same spawning grounds or they live on the same reefs. And those are the ones that are going to be most affected.”
Scientists also found that the decreasing growth rate could be due to higher stress levels from rising temperatures, increased oxygen consumption and inability to swim for long periods.