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Natural Reproductive Success and Demographic Effects of Hatchery-Origin Steelhead in Abernathy Creek, Washington Abernathy Fish Technology Center U.S. Fish and Wildlife Service
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Traditional Hatchery Procedures
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An Alternative Collect & rear natural-origin juveniles to sexual maturity 1) Large #s of fish & low effect on population 2) High Genetic Diversity
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Objectives 1) Assess the overall effects of hatchery supplementation relative to control streams 2) Determine the natural reproductive success of hatchery-origin and natural- origin steelhead
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Comprehensive Approach Hatchery Management & Procedures Cost/Benefit Analysis Direct application to hatcheries with conservation goals Hatchery Production Ecological Behavioral Physiological Suggests means to manipulate Reproductive Success Elucidate Mechanisms Genetics Parentage Hatchery vs. Natural Does it work & direction
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199920002001 Mean SD MeanSD Adult Steelhead Male Length (mm) 410524206244750 Female Length (mm) 402584036042455 Fecundity1313522 1425569 1711626 Hatchery Reared Adult Steelhead Juvenile Collection Year
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Hatchery Methods and Procedures Prior to Release CWT and AD clipped (subset PIT tagged) Genotyped Gill Biopsies
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Steelhead Release N = 20,000 Hatchery origin fish per year Fish released at 3 different times (blocks)
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Hatchery and Natural Emigration Collaborator: IMW Project & WDFW
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Natural Origin Smolt Production
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Smolt Emigration
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Median Travel Date
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Diel Emigration
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Smolt production is equivalent between pre- and post-hatchery production years Hatchery origin fish emigration rates, timing, and patterns are similar to natural origin fish Production/Emigration Summary
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Physiological & Morphological Sampling
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1 2 3 4 5 8 9 10 11 12 13 17 A. Landmarks B. Distances-Truss Network C. Significant discriminant coefficients Morphological Analysis Hatchery migrants were longer than natural migrants
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Na +, K + ATPase Activity 200320042005
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Plasma Na + & Osmolality 2004 2005
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Hatchery and Natural steelhead of similar genetic parentage differ morphologically and physiologically. The observed characteristics provide a baseline measure. We will continue to monitor and determine if adult return rates and reproductive success is affected. Summary
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Adult Steelhead Returns Natural:36 (20 females/16 males) Hatchery:38 (13 females/25 males) Strays:39 (14 females/25 males)
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Relative Fitness Determine if the natural and hatchery fish mate randomly and produce offspring with equal survival rates in Abernathy Creek –Parentage analysis via 11 microsatellite loci Ground truthed the loci and method Estimated error rate (0.8%)
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Relative Fitness –Following our first broodyear (2005) Genetic diversity among the broodstocks was maintained among respective progeny Females on average produced 4.2 and males 3.4 offspring per spawner Natural fish produced 5.83 offspring per spawner Hatchery fish produced 1.40 offspring per spawner
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Smolt production is equivalent between pre- and post-hatchery production years Hatchery fish emigration rates, timing, and patterns are similar to natural fish Hatchery and natural steelhead of similar genetic parentage differ morphologically and physiologically Continuing Research –Relate physiology, morphology, and behavior to adult return rates and reproductive success of succeeding generations –Estimate heritabilities and genetic correlations of fitness-related, life history traits in relation to return timing, age and size at return (maturity) of succeeding generations Conclusions
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