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Old 12-04-2005, 10:51 AM   #48
King Salmon
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Join Date: Jan 2004
Posts: 17,813
Default Re: at the least be informed

Quote from the Hood River Broodstock Study
" old hatchery stocks have much lower total fitness thatn wild fish (17% to 54% of wild fish), but that new stocks have fitness that is similar to that of wild fish (ranging from 85% to 108% of wild fitness)"
Travis, as I stated earlier, there has been another Oct 2004 update published since the Dec 2003 article you are quoting from. Here are the updated fitness numbers again:

In summary, we confirmed that old-stock hatchery fish of STW91 had very low fitness compared to wild steelhead (relative fitnesses of 0.11 and 0.098 for males and females, (respectively), while the conservation-stock hatchery fish of STW95-97 had higher, but more variable relative fitness (0.63-1.21).

Conservation stock hatchery males had relative fitnesses of 0.63, 0.89 and 0.71 that of wild fish in run years 95, 96 and 97, respectively. Hatchery female relative fitnesses were estimated to be 0.68, 0.89 and 1.21, respectively.

When you consider the number of hatchery males included in the study were 106, 114, and 63 (1995, 1996, and 1997 respectively) and hatchery females numbered 72, 168, and 106, then the weighted average for the entire study cohort of 629 fish comes out to a relative fitness of 85.8%

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