UBC Undergraduate Research

An Evaluation of the Extrinsic Stressors Impacting Pacific Herring, Clupea pallasi, Spawn in False Creek Ahmed, Molly; Dykstra, Natalie; Janowicz, Allie; Lam, Samantha

Abstract

Pacific Herring, Clupea pallasi, are essential forage fish along the Northwest Pacific Coast that have always played a crucial role in B.C.'s economy and in the livelihoods of coastal indigenous Peoples. False Creek has historically provided spawning habitat for herring and other species prior to colonisation, urban infill and development. To address the ecological degradation of False Creek, the Squamish Streamkeepers are supporting the reestablishment of herring populations by providing alternative spawning substrate. This is the 5th year of UBC ENVR 400 student involvement in the project. Our goal is to inform management decisions by collecting, analysing, and interpreting data. Our project objectives were to 1) Synthesise all previous ENVR 400 False Creek Herring reports and build an infographic to be shared to build awareness of herring in False Creek. 2) Monitor the 2025 herring spawn and compare it to previous iterations. 3) Evaluate how light exposure and cleaning impacts algal build-up on nets at Fisherman's Wharf. 4) Determine how the conductivity and temperature profiles at Fisherman's Wharf change annually and during the anticipated spawning period. 5) Investigate if 6PPD-Quinone is present in Fisherman’s Wharf. 6) Develop a lab protocol for a 6PPD-Quinone exposure experiment on herring egg development. We found that conductivity and temperature at our study sight was impacted by tidal fluxes, seen by daily fluctuations, and the water temperature was below the ideal spawning range for herring during the anticipated spawning period. Nets that were not cleaned had dense algae coverage, but the effects of algae growth on spawn could not be assessed due to the lack of spawn. Trace concentrations of 6PPD-Q were found in surface samples, but not at depth with 6 out of 14 samples had traces of 6PPD-Q. The sample with the maximum concentration found was collected after a rain event and was 3.37 ng/L. There were some speculations behind low spawn including an increase in predator populations, an increase in catch limit for Food and Bait fisheries in the Strait of Georgia which target resident, pre-spawning populations, sewer construction by the study site and colder and drier temperatures during the spawning period.

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Attribution-NonCommercial-NoDerivatives 4.0 International