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

3. 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

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

6. 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.

7. Portfolio effect ECONOMICS 1.Portfolio of financial assets 2.Invest in diverse assets Combination of multiple, diverse assets minimizes performance risk of the portfolio ECOLOGY 1.Portfolio of populations within a complex 2.Manage for diverse phenotypes Combination of multiple, diverse populations minimizes performance risk of the portfolio

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

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

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

15. Sacramento Basin San Joaquin Basin Uneven abundance

16. Habitat diversity Phenotypic diversity Diverse (asynchronous) population dynamics Stabilizing portfolio effect BRISTOL BAY SALMONRecent research 1 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 1 Schindler et al. 2010. Population diversity and the portfolio effect in an exploited species. Nature 465: 609-612.

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

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

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

20. Nimbus Hatchery on the American River

21. 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

22. Central Valley Chinook life history diversity

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