Stability of Pacific herring in Puget Sound is 2x what it would be without habitat and population diversity.
Text of Portfolio Effect in Puget Sound Herring: ESA 2013 Minneapolis
1. Population diversity in Puget Sound herring: Is there a portfolio effect? Tessa Francis, University of Washington Tacoma Megsie Siple, University of Washington Daniel Schindler, University of Washington Washington Department of Fish and Wildlife
2. Pacific herring in Puget Sound are declining, causes unknown. 21 different sub-populations, associated with shoreline sections. Shoreline armoring is increasing. Do we increase stability of the population by keeping all sub-populations? YES THERE IS A PORTFOLIO EFFECT
3. Redorbit.com!BRANDON COLE / WWW.BRANDONCOLE.COM! Forage fish provide multiple ecosystem services globally
4. The mysterious decline of " Puget Sound herring"
5. Forage fish support iconic Puget Sound species
6. Puget Sound herring have declined in recent decades 0 3,000 6,000 9,000 12,000 15,000 18,000 1973 1978 1983 1988 1993 1998 2003 2008 2013 2018 TONS YEAR Cherry Pt. Squaxin Adult spawner biomass Based on egg deposition surveys Source: WA Department of Fish and Wildlife
7. Puget Sound herring are tightly linked to the shoreline Paul Hanson, NOAA
9. Shoreline armoring is increasing. Does population diversity increase stability of Puget Sound herring?
10. Mid/small cap stocks Large cap stocks Balanced fund Cash The Portfolio Effect: Diversity increases stability
11. 1 2 3 Age diversity 0.01 0.1 1 10 1 Major rivers 0.01 0.1 1 10 1 Streams 0.01 0.1 1 10 1 All the same age 0.01 0.1 1 10 1 year Total return (rela;ve) Bristol Bay 1960 2010
12. Herring subpopulations can contribute 2-5x the average in good years.
13. Puget Sound herring subpopulations are not highly synchronous
14. The Puget Sound herring population is less variable than the individual subpopulations Biomass(standardized) 1980 2010
15. Log(Variance) Log(Mean) z = 2.1 expected observed The Puget Sound herring population is two times more reliable than the individual components of the portfolio Anderson et al. Methods Ecol. Evol. In Press
16. No change Decrease Increase Eelgrass bed trends (2004-2009) 33% of shoreline altered 25% of shoreline armored 2005-2010 Rate of new armoring: 1.8 km/yr
17. Are Puget Sound herring habitat limited?
18. Marc Mangel Tim Essington Alec MacCall Doug Hay Paul Hershberger Dayv Lowry Ole Shelton Tessa Francis Study Panel on Ecosystem Based Management of Puget Sound Forage Fish 1. Status and trends 2. Key Vulnerabilities 3. Ecosystem Needs