Floods Good and Bad for Fish

It looks as though floods are bad for fish that migrate from the seas to the rivers. Then again it looks as if floods are good for fish that live in streams year round and can even improve the habitat.

early hatcheries took their eggs from first-arriving fish to ensure their supply, Gregory said, and fish runs began arriving early. The window for returning fish shrank to a couple of months.
"Then the impact of a single flood on the population could be much greater," he said.

In studies of trout that live in streams year-round, the number of juveniles rises dramatically in the year after a flood, he said.