Event Title

The Role of Egg Predation in Pacific Herring Population Dynamics in the Salish Sea

Presentation Abstract

Forage fish such as Pacific herring (Clupea pallasii) are ecological foundation species in marine and estuarine ecosystems. In the Salish Sea, Pacific herring are an indicator species, and the regional management agency, the Puget Sound Partnership, has set recovery targets to guide herring management. Salish Sea herring are spatially and temporally segregated into individual subpopulations by their spawning behavior, and these subpopulations show asynchronous abundance trends over the past several decades. Some local spawning subpopulations have significantly declining trends. Here we focus on the embryonic stage as a potential limiting stage for herring, describing variability in hatch rates across different subpopulations, and assessing the relative importance of predation in determining herring egg hatch success. We then explore the implications of predation rates for observed local trends in herring biomass. Using a combination of in situ incubations and predation exclusion devices, we estimated herring egg survival rates both in the presence and absence of large predators, across multiple spawning subpopulations in the Salish Sea. We found that predation accounted for approximately 50% of egg loss across all spawning populations. We link predation rates to 40+ years of herring biomass estimates for each spawning population and trends in major egg predators (diving ducks) to develop hypotheses about stressors that limit recovery of herring in the Salish Sea.

Session Title

Ecological and cultural context of Pacific herring in the Salish Sea

Conference Track

Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)

Document Type

Event

Location

2016SSEC

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

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The Role of Egg Predation in Pacific Herring Population Dynamics in the Salish Sea

2016SSEC

Forage fish such as Pacific herring (Clupea pallasii) are ecological foundation species in marine and estuarine ecosystems. In the Salish Sea, Pacific herring are an indicator species, and the regional management agency, the Puget Sound Partnership, has set recovery targets to guide herring management. Salish Sea herring are spatially and temporally segregated into individual subpopulations by their spawning behavior, and these subpopulations show asynchronous abundance trends over the past several decades. Some local spawning subpopulations have significantly declining trends. Here we focus on the embryonic stage as a potential limiting stage for herring, describing variability in hatch rates across different subpopulations, and assessing the relative importance of predation in determining herring egg hatch success. We then explore the implications of predation rates for observed local trends in herring biomass. Using a combination of in situ incubations and predation exclusion devices, we estimated herring egg survival rates both in the presence and absence of large predators, across multiple spawning subpopulations in the Salish Sea. We found that predation accounted for approximately 50% of egg loss across all spawning populations. We link predation rates to 40+ years of herring biomass estimates for each spawning population and trends in major egg predators (diving ducks) to develop hypotheses about stressors that limit recovery of herring in the Salish Sea.