1. Accounting for multiple pathways in the connections among climate variability, ocean processes, and coho salmon recruitment in the Northern California Current
- Author
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Malick, Michael J., Cox, Sean P., Peterman, Randall M., Wainwright, Thomas C., and Peterson, William T.
- Subjects
California -- Environmental aspects ,Silver salmon -- Environmental aspects ,Climatic changes ,Earth sciences - Abstract
Pathways linking climate to population dynamics of higher-trophic-level fish species such as Pacific salmon often involve a hierarchy in which regional-scale physical and biological processes mediate the effects of large-scale climate variability. We used probabilistic networks to investigate 17 potential ecological pathways linking climate to Oregon coho salmon (Oncorhynchus kisutch) recruitment. We found that pathways originating with the Pacific Decadal Oscillation were the most influential on recruitment, with the net effect being two to four times greater than for pathways originating with the North Pacific Gyre Oscillation or the Oceanic Nino Index. Among all environmental variables, sea surface temperature and an index of juvenile salmon prey biomass had the greatest effects on recruitment, with a 76% chance of recruitment being equal to or below average given that ocean temperatures were above average and a 34% chance of recruitment being below average given that prey biomass was above average. Our results provide evidence that shifts in climate patterns could strongly influence recruitment simultaneously through multiple ecological pathways and highlight the importance of quantifying cumulative effects of these pathways on higher-trophic-level species. Les voies qui relient le climat a la dynamique des populations d'especes de poissons de niveau trophique eleve comme les saumons du Pacifique definissent une hierarchie dans laquelle des processus physiques et biologiques a l'echelle regionale modulent les effets de la variabilite a grande echelle du climat. Nous avons utilise des reseaux probabilistes pour etudier 17 voies ecologiques potentielles reliant le climat au recrutement du saumon coho (Oncorhynchus kisutch) de l'Oregon. Nous avons constate que les voies emanant de l'oscillation decennale du Pacifique exercent la plus grande influence sur le recrutement, leur effet net etant de deux a quatre fois superieur a celui des voies qui emanent de l'oscillation du tourbillon nord-pacifique ou de l'indice Nino oceanique. De toutes les variables environnementales, la temperature de la surface de la mer et un indice de biomasse des proies des saumons juveniles avaient les plus grands effets sur le recrutement, avec une probabilite de 76 % que le recrutement soit egal ou inferieur a la moyenne etant donne que les temperatures de l'ocean etaient superieures a la moyenne et une probabilite de 34 % que le recrutement soit inferieur a la moyenne etant donne que la biomasse de proies etait superieure a la moyenne. Nos resultats fournissent des preuves appuyant la these voulant que des changements des regimes climatiques puissent exercer simultanement une forte influence sur le recrutement par l'entremise de multiples voies ecologiques et ils soulignent l'importance de quantifier les effets cumulatifs de ces voies sur les especes de niveau trophique eleve. [Traduit par la Redaction], Introduction Pacific salmon (Oncorhynchus spp.) populations along the Northeast Pacific coast exhibit large interannual and interdecadal fluctuations in adult abundances. Changes in large-scale climate patterns are often associated with variability [...]
- Published
- 2015
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