U.S. scientists have found that more than one in five fish deaths in the state between 2004 and 2014 were closely associated with heat waves and warmer average surface water temperatures in lakes, according to the findings of the study published in the journal Nature Climate Change on Monday.
The researchers from Reed College in Portland, Oregon and the University of California, Davis (UC Davis), reviewed a database of 502 freshwater fish die-offs in Wisconsin in combination with lake-specific temperature profiles simulated for north temperate lake ecosystems.
They discovered that mass mortality events for freshwater fish population often took place in lakes where water temperature was warmer than lakes without die-offs, and the fish deaths were also reported during the years of high water temperatures. The scientists built a climate projection model to forecast fish deaths from warming summer temperatures over the next several decades.
They predicted that global temperature is set to increase two degrees Celsius by 2100, and the warmer climate will push up the die-offs in Wisconsin lakes by four times, particularly at southern latitudes.
“This study is unveiling another reality of what climate change will look like for north-temperate lakes across the world,” said the study’s co-author Andrew Rypel, an associate professor at UC Davis. Global warming creates a big problem for fishes in landlocked lakes, where they have little ability to adapt to changing climates by migrating, he said. RSS/Xinhua
