A new study suggests that it could, particularly if hatchery fish supplement the stocks of a threatened or endangered species.

Some hatchery fish have been introduced in an attempt to mitigate the losses.

Nevertheless, the growing reliance on hatchery fish raises questions about the long-term health of the salmon population.

"It's time that we articulate what the proper role of hatchery fish is when we make a listing."

A typical compromise on some streams is to augment the natural populations with hatchery fish.

Triploid fish are exposed to the same environment as all other hatchery fish.

Infected hatchery fish have been poisonous to Colorado's wild system.

This can happen if hatchery fish whose parents came from one stream are introduced into another stream with a different environment.

One way to reduce the mismatch between wild and hatchery fish is to make hatcheries more natural.

"You have to look at the hatchery fish, and they have largely been ignored," he said.