Salmon and jellies and herring, oh my! Abiotic and biotic-dependent trends in abundance and distribution of pelagic critters in Skagit Bay across 17 years

Publication Year:
2018
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Repository URL:
https://cedar.wwu.edu/ssec/2018ssec/allsessions/415
Author(s):
Munsch, Stuart; Greene, Correigh; Hall, Jason; Salish Sea Ecosystem Conference (Seattle, WA : 2018)
Publisher(s):
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Tags:
Fresh Water Studies; Life Sciences; Marine Biology; Natural Resources and Conservation; Terrestrial and Aquatic Ecology
artifact description
As a large fjord, the Salish Sea exhibits strong spatiotemporal variation in temperature and salinity due to various marine and freshwater inputs. These patterns are particularly evident in Skagit Bay where water conditions are influenced by marine inputs from Deception Pass and Saratoga Passage and seasonal pulses of fresh water from Skagit River. We investigated how abundance and community composition in pelagic surface waters of Skagit Bay varied from 2001-2017, and how temperature and salinity patterns can influence which species predominate in particular years. Data come from long-term monitoring of Skagit Bay using a Kodiak surface trawl that sweeps the uppermost 10 feet of the water column. We evaluated how temperature and salinity influenced species abundance and distribution and tested whether distributions were likely influenced by biotic interactions (e.g. predation, competition), focusing on diadromous species (e.g., salmon, lamprey, starry flounder), forage fish (e.g., Pacific herring, surf smelt, Pacific sandlance), and gelatinous zooplankton (e.g., ctenophores, scyphozoan and hydrozoan medusae). Our results provide evidence for strong abiotic structuring and weaker effects from biotic interactions, although certain species appeared to interact more than others. These results may help us understand how long-term increases in regional and local temperatures and freshening waters will affect Salish Sea ecology.