A study published in the journal Nature Climate Science Monday found at least a 100 fish die-offs in Wisconsin between 2004 and 2014 were strongly linked with warmer summer temperatures fueled by climate change. Already, some species, such as walleyes and cisco, are experiencing declines because of warming water temperatures. And it's only going to get worse if humans don't act. The die-offs in Wisconsin’s lakes are expected to double by mid-century and quadruple by 2100 and there could be significantly more fish die-offs as global temperatures increase.