Sunday, October 3, 2010

Science Based Management Improvements by ODFW

ODFW Policy Change Favors Wild Native Fish

There are some encouraging improvements in conservation management of salmonids being carried out by the Oregon Department of Fish and Wildlife.  The following case studies document the changes and the response of wild salmon and steelhead.

Oregon Coho Salmon:

From 1960 to 1990 the ODFW policy was to use natural habitats to rear hatchery coho salmon and the 1980 Coho Plan dedicated the lower Columbia River to coho hatchery production and harvest. By 1990 10 million hatchery coho were being released annually.  Form 1934 to 1990 pre-smolts were released, but those came to an end after 1990 when mostly smolts were released.  The releases were reduced to 4.5 million smolts.  In 2010 pre-smolt releases were ended and releases into natural habitats were ended.  Lower Columbia on-station hatchery releases were reduced to 45% of the 1990 releases and fewer locations were used.  Coastal hatchery on-station releases were reduced to 11% of the 1990 level and there are fewer release locations.  Oregon wild coho salmon abundance has increased (1990-2007) in response to the change in hatchery policy and other environmental factors. 

Hatchery impacts on the productivity of wild coho salmon documented in the scientific literature necessitated a change in management.  The listing of Oregon coastal and lower Columbia River coho salmon under the Endangered Species Act created an important incentive. 

Scientific studies going back to 1986 provided the following information:  Nickelson et al. 1986 demonstrated that the planting of hatchery coho pre-smolts into natural habitats depressed natural productivity; Lichatowich and McIntyre 1987 demonstrated an association with increased hatchery coho releases decreased coho harvest and declining wild coho abundance in Oregon; Flagg et al. 1995 said the combination of hatchery programs and harvest was driving lower Columbia River coho to extinction; Nickelson 2003 said hatchery coho smolt releases depressed the productivity of wild coho on the Oregon coast, and Buhle et al. 2008 said hatchery coho spawners on the Oregon coast had density-dependent effects on natural productivity.

The shift in hatchery management policy by ODFW has contributed to the increasing trend in wild coho salmon in coastal and lower Columbia River populations.  Whether it is enough to actually protect wild coho by improving their abundance, productivity, diversity and distribution remains to be seen.  At least a  50 year policy of trying to replace wild salmon and their habitats with hatchery programs is beginning to change.

Siletz River Wild Summer Steelhead:

Siletz Falls creates a passage barrier to winter steelhead, fall chinook, and coho salmon during winter flows.  Natural barriers like Siletz Falls are responsible for providing habitat for fish that can pass during the spring and summer flows, habitat that favors spring chinook and especially summer steelhead. 

In 1952 a fish ladder was constructed at Siletz Falls and opened up the river above the falls to winter steelhead, coho, and fall chinook passage.  The ODFW also started up hatchery programs for the release of winter steelhead, summer steelhead, coho and cutthroat trout by releasing smolt and parr in the 1960s.  Monitoring results show that while hatchery fish increased wild steelhead and spring chinook rapidly declined.  For 22 years from 1972 to 1994 the ODFW did no monitoring of this hatchery and fish passage program, but when it re-started again they discovered that there were fewer than 100 wild fish while 92% of the fish were of hatchery or non-native origin. 

In order to salvage the wild summer steelhead above the falls the ODFW eliminated passage of all hatchery and non-native salmonids, but continued to release hatchery summer steelhead until 1999.  In response, the wild spring chinook population stabilized and the wild summer steelhead population has increased from less than 100 fish to a range of 400 to 900 fish following the termination of the hatchery summer steelhead program and blocking access to hatchery and non-native salmonids at the falls. The river above the falls has been restored to its natural condition and is more productive for native salmonids as a result.


Kostow, Kathryn. 2010. Strategies for mitigating ecological effects of hatchery programs: Some case studies from the Pacific Northwest.  State of the Salmon. Ecological Interactions Between Wild and Hatchery Salmon.  May 4-7, 2010. Portland, Oregon.

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