Abstract Title

Session S-03D: Forage Fish Research and Protection in the Salish Sea

Keywords

Species and Food Webs

Location

Room 611-612

Start Date

30-4-2014 3:30 PM

End Date

30-4-2014 5:00 PM

Description

Small-scale genetic and demographic diversity can stabilize populations on a larger scale. However, subpopulations of pelagic fish species can be difficult to distinguish. Here, we examine demographic diversity in 21 stocks of Pacific herring (Clupea pallasii) in Puget Sound, USA using a multivariate auto-regressive state-space (MARSS) model, and data from both acoustic surveys paired with trawls, and subtidal egg surveys to estimate population growth trends. Herring populations associated with individual spawning beaches are asynchronous, but share a common negative growth rate across the Puget Sound estuary. We found that both survey techniques observe the same underlying demographic processes, and that egg surveys are a more accurate estimator of total spawning biomass. We used states obtained from MARSS analysis to measure portfolio effects in Puget Sound herring, and found that the Puget Sound population as a whole is stabilized by the presence of several separate spawning subpopulations. Available environmental data was not sufficient to explain variations in spawning biomass; however, herring may respond to spawning site conditions that aren’t currently measured.

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Apr 30th, 3:30 PM Apr 30th, 5:00 PM

Biocomplexity in Pacific herring (Clupea pallasii) of Puget Sound, USA

Room 611-612

Small-scale genetic and demographic diversity can stabilize populations on a larger scale. However, subpopulations of pelagic fish species can be difficult to distinguish. Here, we examine demographic diversity in 21 stocks of Pacific herring (Clupea pallasii) in Puget Sound, USA using a multivariate auto-regressive state-space (MARSS) model, and data from both acoustic surveys paired with trawls, and subtidal egg surveys to estimate population growth trends. Herring populations associated with individual spawning beaches are asynchronous, but share a common negative growth rate across the Puget Sound estuary. We found that both survey techniques observe the same underlying demographic processes, and that egg surveys are a more accurate estimator of total spawning biomass. We used states obtained from MARSS analysis to measure portfolio effects in Puget Sound herring, and found that the Puget Sound population as a whole is stabilized by the presence of several separate spawning subpopulations. Available environmental data was not sufficient to explain variations in spawning biomass; however, herring may respond to spawning site conditions that aren’t currently measured.