Presentation Abstract

Pacific herring are a foundational species in the Salish Sea, providing important cultural, social, economic, and ecological benefits throughout the ecosystem. While herring are common across the Salish Sea, patterns of their abundance in recent years vary spatially. Herring are subject to many factors that may influence their abundance and distribution, but there is no agreement on what the key factors are or, therefore, how to address local declines and support herring resilience. Here, we present results from a qualitative network model of the herring ecological system evaluating the relative support for the influence of different possible factors on herring populations in the Salish Sea. Expert elicitation and data synthesis were used to develop a conceptual model of herring, their food web, environmental drivers (including plankton), and hypotheses about key stressors on herring populations, including shoreline development, disease, predation, fishing, and prey limitation. Based on this conceptual model, a qualitative network model is developed, which directly connects ecosystem components using positive, negative, or neutral links. By simulating perturbations via an increase in one or more nodes, and comparing predicted outcomes to data observations, the model evaluates the relative support for each potential stressor, and multiple stressors in aggregate, as limiting factors for herring populations in the Salish Sea. By accounting for indirect effects and positive and negative feedbacks, the qualitative network model allows for comparisons between scenarios under which individual and multiple factors have direct impacts on herring at different life stages. This tool will thus identify which are the key factors linked to observed changes in the abundance and distribution of herring, and therefore what management actions can be taken to ensure the resilience of this critical resource.

Session Title

Modeling Change in the Transboundary Salish Sea

Keywords

Herring, Salish Sea, Qualitative model

Conference Track

SSE15: Data and Information Management

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE15-470

Start Date

5-4-2018 1:45 PM

End Date

5-4-2018 2:00 PM

Type of Presentation

Oral

Contributing Repository

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

Geographic Coverage

Salish Sea (B.C. and Wash.)

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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Apr 5th, 1:45 PM Apr 5th, 2:00 PM

Key factors influencing change in Pacific herring populations: a qualitative network model approach

Pacific herring are a foundational species in the Salish Sea, providing important cultural, social, economic, and ecological benefits throughout the ecosystem. While herring are common across the Salish Sea, patterns of their abundance in recent years vary spatially. Herring are subject to many factors that may influence their abundance and distribution, but there is no agreement on what the key factors are or, therefore, how to address local declines and support herring resilience. Here, we present results from a qualitative network model of the herring ecological system evaluating the relative support for the influence of different possible factors on herring populations in the Salish Sea. Expert elicitation and data synthesis were used to develop a conceptual model of herring, their food web, environmental drivers (including plankton), and hypotheses about key stressors on herring populations, including shoreline development, disease, predation, fishing, and prey limitation. Based on this conceptual model, a qualitative network model is developed, which directly connects ecosystem components using positive, negative, or neutral links. By simulating perturbations via an increase in one or more nodes, and comparing predicted outcomes to data observations, the model evaluates the relative support for each potential stressor, and multiple stressors in aggregate, as limiting factors for herring populations in the Salish Sea. By accounting for indirect effects and positive and negative feedbacks, the qualitative network model allows for comparisons between scenarios under which individual and multiple factors have direct impacts on herring at different life stages. This tool will thus identify which are the key factors linked to observed changes in the abundance and distribution of herring, and therefore what management actions can be taken to ensure the resilience of this critical resource.