PowerPoint Presentation
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Plasma 11-ketotestosterone (11-KT)
- Major androgen in teleost fish
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- Instrumental in the regulation of spermatogenesis
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Critical periods for maturation decision – based on body size/growth rate
Comparison of wild and hatchery
growth and minijack rates
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Conclusions
- Growth modulation successfully reduced minijack rates
- It also significantly reduced both juvenile and adult survival-size matters
- The Yakima HxH line shows consistently lower minijack rates than the supplemented line.
- High numbers of minijacks appear to migrate downstream in the spring
- Increased egg incubation temperatures significantly alter life-history composition-global climate change effects?
- Further research is needed to develop hatchery rearing protocols that will not alter life-history composition of hatchery stocks
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