North Pacific Anadromous Fish Commission

Technical Report 18

Table of Contents

Salmon Returns in the Northeast Pacific in Relation to Expedition Observations (and Next Steps)

Brian E. Riddell, Kathrine G. Howard, and Andrew R. Munro

Abstract Excerpt:
As the previous reports to this workshop have demonstrated, there have been numerous significant new findings and new questions. The expeditions were an extension of a salmon research program in the Salish Sea ( and intended to test the hypotheses that survival through the first winter-at-sea was a major determinant of year-class strength in Pacific salmon Oncorhynchus spp. However, to test this hypothesis there was limited knowledge of where specific populations of salmon rear, and very little experience in sampling juvenile salmon on the high-seas particularly in relation to their winter ecology. Based on the success of juvenile salmon surveys in Russia, it was proposed to test surface trawls as sampling gear. Both 2019 and 2020 trawl surveys were successfully completed, covered similar geographic areas (Fig. 1), and captured all species of Pacific salmon (Table 1), but they caught many fewer salmon than expected. In hindsight, however, there is very limited ability to compare our expectations with observations from these new projects. This paper considers what we can learn from these surveys, including the ability of the surface trawl to representatively sample the fish population vulnerable to the trawl net. The latter is compared against a sample of relative abundance indices for Pacific salmon from Alaska southward to the Columbia River.

*This is the first paragraph of an extended abstract. Download the full abstract below.



Riddell, B.E., K.G. Howard, and A.R. Munro.  2022.  Salmon returns in the Northeast Pacific in relation to expedition observations (and next steps).  N. Pac. Anadr. Fish Comm. Tech. Rep. 18: 115–139.