ASTORIA, Ore. (AP) — Wildlife officials in Oregon have voted to end a summer steelhead hatchery program on the North Umpqua River after severe declines in the number of wild steelhead returning from the Pacific Ocean each summer, agency officials and environmentalists said.

The 4-3 vote by the Oregon Fish and Wildlife Commission transitions the agency to a “wild fish only” management plan in an attempt to help the genetically distinct wild summer steelhead bounce back. Wild winter steelhead, which do not have a hatchery program, remain strong. No smolts were released into the North Umpqua last summer either because of wildfires.

Environmental groups said they owed the commission a “debt of gratitude” for taking the vote. State officials closed sport fishing on the Umpqua and North Umpqua rivers last summer in response to record-low wild summer steelhead returns.

“We are thrilled to see the Commission end the hatchery summer steelhead program,” said Karl Konecny of the group Steamboaters, which is part of a coalition of environmental and angler groups that supported an end to the hatchery program. “The continued presence of hatchery fish on the spawning beds would have slowed the recovery and depressed the eventual size of the wild steelhead run.”

Earlier this spring, state wildlife officials published an assessment of wild summer steelhead health throughout the North Umpqua basin and initiated critical monitoring programs for future runs.

Studies have shown that hatchery-bred steelhead can weaken the gene pool of their wild counterparts and make it more difficult for wild fish to successfully reproduce. They can also harm wild fish because they compete with those populations for resources.

The North Umpqua River is a 106-mile-long (170-kilometer-long) tributary of the Umpqua River in southwestern Oregon.