Salmon are not healthy in warm water. As the rivers of Alaska get warmer, the salmon there get sicker. Just one more reason food prices are rising, a larger proportion of the salmon caught in Alaska are being thrown to the dogs.
In the lower 48 states the salmon season now is heavily restricted or gone entirely because of diminished salmon populations.
What's wrong with warmer temperatures in water? More parasites and more diseases thrive. Thus more sick fish.
Previous research has blamed global warming for epidemics wiping out numerous species of amphibia. High altitude habitat is disappearing and many species are thus endangered, from bugs to birds.
Some health scientists have predicted the same for us humans. More widespread infection from diseases traditionally limited to the tropices like dengue fever. I guess the limited upside here is that a smaller human population will use fewer resources and thus produce fewer greenhouse gas emissions. The GAIA folks would say this is the earth's way of protecting itself. I would say it could be the result of a growing environmental debt that we eventually must pay in full.