Declines of juvenile coastal cutthroat trout and coho salmon over fifteen years in a salmon-bearing stream in the Salish Sea

Authors

Anne-Marie Flores, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, CanadaFollow
Morgan M. Davies, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, CanadaFollow
Katrina Kushneryk, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, CanadaFollow
Pippi T.E.S. Lawn, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, CanadaFollow
Sibylla Helms, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, CanadaFollow
Hanna M. Thomson, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, CanadaFollow
Kyle R. Nelson, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, Canada; School of Environmental Studies, University of Victoria, British Columbia, CanadaFollow
Christopher W. Burns, LGL Environmental Research Associates Ltd., Sidney, British Columbia, CanadaFollow
Steven Roias, LGL Environmental Research Associates Ltd., Sidney, British Columbia, CanadaFollow
Travis G. Gerwing, Gulf Islands National Park Reserve, Parks Canada, Sidney, British Columbia, Canada; Department of Biology, University of Victoria, Victoria, British Columbia, CanadaFollow

Abstract

Pacific salmon are ecologically, economically, and culturally important species indigenous to British Columbia, Canada. Unfortunately, some populations of Pacific salmon have been declining due to climate change, habitat loss, overfishing, and anthropogenic development. As such, considerable resources have been invested to study, restore, protect, and monitor Pacific salmon and their habitat. Since 2004, Lyall Creek, a salmon-bearing stream in the Salish Sea in British Columbia, Canada, has been monitored. Using 2-pass electrofishing, we investigated changes in observed densities over 15 years (2004–2019) for juvenile coho salmon (Oncorhynchus kisutch) and juvenile coastal cutthroat trout (Oncorhynchus clarkii clarkii) that inhabit Lyall Creek. A statistically insignificant but general decreasing trend was observed for juvenile coho salmon densities over 15 years in Lyall Creek. Juvenile coastal cutthroat trout densities in Lyall Creek exhibited a statistically significant decline. More research is required to understand what anthropogenic and environmental factors are negatively influencing Pacific salmon densities in Lyall Creek. Specifically, water availability may be an important stressor affecting these salmon populations.


El salmón del Pacífico es una especie autóctona de British Columbia (Canadá) de gran importancia ecológica, económica y cultural. Desafortunadamente, algunas poblaciones de salmón del Pacífico han ido disminuyendo como resultado del cambio climático, la pérdida de hábitat, la pesca indiscriminada y el desarrollo antropogénico. Por tal motivo, se han invertido considerables recursos para estudiar, restaurar, proteger y monitorear al salmón del Pacífico y su hábitat. Desde el año 2004, se ha monitoreado el arrollo Lyall Creek en Salish Sea en British Columbia, Canadá. Durante un período de 15 años (2004–2019), investigamos los cambios en la densidad de juveniles de salmón coho (Oncorhynchus kisutch) y de trucha degollada (Oncorhynchus clarkii clarkii) que habitan en Lyall Creek, utilizando el método de electropesca de dos pasadas. Durante los 15 años de estudio, se observó una tendencia general decreciente de la densidad de juveniles de salmón coho. Sin embargo, dicha tendencia no fue estadísticamente significativa. Mientras que, la densidad de juveniles de truchas degolladas costeras en Lyall Creek sí exhibió una disminución estadísticamente significativa. Para conocer cuáles son los factores antropogénicos y ambientales que influyen negativamente en la densidad del salmón del Pacífico en Lyall Creek, es necesario llevar a cabo más trabajo de investigación. Específicamente, la disponibilidad de agua puede ser un importante factor adverso que enfrentan estas poblaciones de salmón.

Recommended Citation

Flores, Anne-Marie; Davies, Morgan M.; Kushneryk, Katrina; Lawn, Pippi T.E.S.; Helms, Sibylla; Thomson, Hanna M.; Nelson, Kyle R.; Burns, Christopher W.; Roias, Steven; and Gerwing, Travis G. (2021) "Declines of juvenile coastal cutthroat trout and coho salmon over fifteen years in a salmon-bearing stream in the Salish Sea," Western North American Naturalist: Vol. 81: No. 4, Article 7.
Available at: https://scholarsarchive.byu.edu/wnan/vol81/iss4/7