Thursday, May 13, 2010

Another Good Reason To Spill


The John Day River in central Oregon represents one of the most productive and wild rivers remaining in the Columbia River system. No hatchery salmon or steelhead are released into the basin and in general steelhead and chinook in the John Day are doing much better than other nearby watersheds. Unfortunately since 2000, an estimated 23% of spawners in the John Day Basin have been hatchery strays and some years strays have made up more than 40% of spawning steelhead. The majority of these strays come from Snake River hatchery programs hundreds of miles away. High numbers of hatchery strays in a watershed managed as a wild salmonid refuge is a big problem and ODFW biologists believe that hatchery spawners in the John Day are depressing the productivity of wild steelhead in the basin and may be a primary factor in an overall downward trend in steelhead populations in the basin.

It has long been thought that high levels of straying in Snake River hatchery populations was largely due to the practice of barging and now two ODFW researchers have published research confirming that hypothesis. Using coded wire tags implanted in smolts at their hatchery of origin and a tag array in the John Day designed to record when tagged fish passed upriver, they found that almost none of the fish allowed to migrate naturally through the river strayed into the John Day, while high numbers of barge transported fish strayed. These findings highlight the need to manage for spill or remove Snake River dams altogether. Barging is unnatural bandaid applied to a hemorrhaging wound and it is having the unintended consequence of threatening the genetic integrity and productivity of wild steelhead stocks throughout the lower Columbia and Snake. Given the high numbers of hatchery fish released from Snake River hatcheries the problem posed by high stray rates is substantial.

See the report here...

http://www.nwcouncil.org/library/isab/2010-2/John%20Day%20Stray%20Summary%20Ruzycki%20Carmichael.pdf

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