Speaker

Heidi Stewart

Streaming Media

Presentation Abstract

Pacific herring play a critical role in the food web of the Salish Sea. Because they are not charismatic megafauna there has been a lack of attention on the species, resulting in a limited understanding of their population dynamics and downward trends in their populations. The Cherry Point stock, centered 30 miles north of Bellingham Bay, has declined roughly 97% since the 1970s. This massive decline is a point of concern for environmental and fishery managers and has led to research into both the initial decline and its lack of recovery. One key hypothesis in need of research is whether the Cherry Point stock is experiencing increased predation from the nearshore fish, bird, and invertebrate community due to its late spawn timing and spawning behavior. To that end, we investigated predation on spawn by deploying predator exclusion enclosures and remote underwater time lapse cameras at spawning locations of both the declining Cherry Point stock and a nearby stock with stable population trends, Semiahmoo Bay. This study aimed to understand (1) whether the impact of predation has a significant effect on egg survival on the Cherry Point spawn, (2) how predation differs between Cherry Point and Semiahmoo Bay, and (3) if fish, birds, and invertebrates of the nearshore community aggregate at spawning sites and utilize Pacific herring spawn as a pulse resource. Our initial work in 2021 showed that there are a variety of species that feed on Pacific herring eggs and the nearshore predator community changes with the presence of spawn. An additional field season in 2022 will address the lack of recovery at Cherry Point and the ecological interactions between Pacific Herring eggs and the nearshore community to understand the impact of a declining population.

Session Title

Salmon Management & Marine Survival

Conference Track

SSE4: Fish Science and Policy

Conference Name

Salish Sea Ecosystem Conference (2022 : Online)

Document Type

Event

SSEC Identifier

SSE-traditionals-286

Start Date

27-4-2022 9:45 AM

End Date

27-4-2022 11:15 AM

Type of Presentation

Oral

Genre/Form

conference proceedings; presentations (communicative events)

Subjects – Topical (LCSH)

Pacific herring--Effect of predation on--Washington (State)--Cherry Point; Pacific herring--Eggs--Washington (State)--Cherry Point; Pacific herring--Predators of--Washington (State)--Cherry Point; Pacific herring populations--Washington (State)--Cherry Point; Fish declines--Washington (State)--Cherry Point

Geographic Coverage

Cherry Point (Wash.)

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

Type

Text

Language

English

Format

Video

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Apr 27th, 9:45 AM Apr 27th, 11:15 AM

Impacts of Predation on Pacific Herring Egg Survival in the Southern Salish Sea

Pacific herring play a critical role in the food web of the Salish Sea. Because they are not charismatic megafauna there has been a lack of attention on the species, resulting in a limited understanding of their population dynamics and downward trends in their populations. The Cherry Point stock, centered 30 miles north of Bellingham Bay, has declined roughly 97% since the 1970s. This massive decline is a point of concern for environmental and fishery managers and has led to research into both the initial decline and its lack of recovery. One key hypothesis in need of research is whether the Cherry Point stock is experiencing increased predation from the nearshore fish, bird, and invertebrate community due to its late spawn timing and spawning behavior. To that end, we investigated predation on spawn by deploying predator exclusion enclosures and remote underwater time lapse cameras at spawning locations of both the declining Cherry Point stock and a nearby stock with stable population trends, Semiahmoo Bay. This study aimed to understand (1) whether the impact of predation has a significant effect on egg survival on the Cherry Point spawn, (2) how predation differs between Cherry Point and Semiahmoo Bay, and (3) if fish, birds, and invertebrates of the nearshore community aggregate at spawning sites and utilize Pacific herring spawn as a pulse resource. Our initial work in 2021 showed that there are a variety of species that feed on Pacific herring eggs and the nearshore predator community changes with the presence of spawn. An additional field season in 2022 will address the lack of recovery at Cherry Point and the ecological interactions between Pacific Herring eggs and the nearshore community to understand the impact of a declining population.