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Stephanie Carlson 1 and William Satterthwaite 2

Managing for population diversity and stability: examples and potential hatchery applications. Stephanie Carlson 1 and William Satterthwaite 2 1 Department of Environmental Science, Policy & Management, UC Berkeley 2 NOAA-Fisheries, Santa Cruz.

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Stephanie Carlson 1 and William Satterthwaite 2

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  1. Managing for population diversity and stability: examples and potential hatchery applications Stephanie Carlson1 and William Satterthwaite2 1 Department of Environmental Science, Policy & Management, UC Berkeley 2 NOAA-Fisheries, Santa Cruz Cal-Neva AFS Annual Meeting, Sacramento: March 27, 2014

  2. Small streams (low water levels lead to stranding mortality, intense bear predation) Large rivers (stable flows, minimal bear predation) Lake beaches (spawning occurs where there is upwelling or wind driven currents, no bear predation, large gravels) Photo credits: N. Kendall, T. Quinn, A. Hendry

  3. Among population variation in: • phenology, • age complexity & degree of overlapping generations, • fecundity

  4. Variation among populations Photo credits: T. Quinn The biocomplexity of the stock structure has also played an critical role in providing stability and sustainability. Here we provide evidence for the effects of biocomplexity on sustainability and emphasize that conserving biocomplexity within fish stocks is important for maintaining their resilience to future environmental change. – Hilborn et al. 2003, p. 6564 Hilborn et al. 2003. Biocomplexity and fisheries sustainability. Proceedings of the National Academy of Sciences 100: 6564-6568.

  5. ECONOMICS Portfolio of financial assets Invest in diverse assets Combination of multiple, diverse assets minimizes performance risk of the portfolio ECOLOGY Portfolio of populations within a complex Manage for diverse phenotypes Combination of multiple, diverse populations minimizes performance risk of the portfolio Portfolio effect

  6. Quantifying buffering induced by the PE Adult production (escapement + catch) Pop1 Pop2 Coefficient of variation (S.D. / mean) Pop1 = 99871 / 198817 = 0.502 Pop2 = 74600 / 138757 = 0.538

  7. Pop1 Pooled (total) returns Quantifying buffering induced by the PE Adult production (escapement + catch) Pop2 Coefficient of variation (S.D. / mean) Pop1 = 99871 / 198817 = 0.502 Pop2 = 74600 / 138757 = 0.538 Pooled returns = 129650 / 337574 = 0.384

  8. Synchronous population dynamics Sacramento Basin • 8 / 10 pairwise correlations were positive, 4 of these were significant San Joaquin Basin • 6 / 6 pairwise correlations were positive, 4 of these were significant

  9. Uneven abundance San Joaquin Basin Sacramento Basin

  10. BRISTOL BAY SALMON Recent research1 has revealed salmon returns to Bristol Bay were 41-77% more stable depending on the scale of aggregation (as measured by reduction in coefficient of variation in production), than the variability in individual stocks Stabilizing portfolio effect Diverse (asynchronous) population dynamics Phenotypic diversity Habitat diversity 1 Schindler et al. 2010. Population diversity and the portfolio effect in an exploited species. Nature 465: 609-612.

  11. Spawning Adult Eggs Fry FRESHWATER Mature Adult MARINE Smolt Ocean Sub-Adult Slide courtesy of C. Phyllis, artwork by J. Moore

  12. Timing of ocean entry: Match-mismatch dynamics Stabilizing portfolio effect Diverse (asynchronous) population dynamics Prey availability Phenotypic diversity Habitat diversity Migration date

  13. Extensive outplanting of hatchery-produced salmon smolts Merced River San Pablo Bay http://www.fisheryfoundation.org/ In 2008, 20.2 million smolts outplanted to San Pablo Bay!

  14. Nimbus Hatchery on the American River

  15. Homogenizing influence of hatcheries • Simplified life histories (e.g., functional semelparity in steelhead) • Simplified age structure (age/stage at release, age at maturity) • Simplified size and timing of release

  16. Central Valley Chinook life history diversity

  17. BRISTOL BAY SALMON CENTRAL VALLEY SALMON VS. Instability, high risk of collapse Stabilizing portfolio effect Synchronous population dynamics Diverse (asynchronous) population dynamics Hatchery mgmt Life history homogenization Phenotypic diversity Habitat lost (e.g., due to dams) and simplified (e.g., due to levees) Habitat diversity

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