Streaming Media
Presentation Abstract
During their marine life stage, Chinook (Oncorhynchus tshawytscha) and Coho Salmon (Oncorhynchus kisutch) from watersheds connected to the Salish Sea display two distinct migration phenotypes; Salish Sea resident and out-migrant. Knowledge of Chinook and Coho marine migrations has been limited to tagged individuals caught by anglers and researchers. It is unclear how fishing effort and angler compliance, as well as other factors influence the proposed migration pathways undertaken by different stocks. Amongst the migrant phenotype, these salmon may only move as far as the continental shelf just off the coast of Washington and Vancouver Island, or they may migrate offshore into the Gulf of Alaska. It is unknown how environmental and genetic factors cause some salmon to remain resident in the Salish Sea and others to out-migrate. These different migration pathways influence contaminant burden of these salmon and the degree to which they are exposed to local versus global sources. It is currently unknown which migration paths would lead to increased contaminant burdens as it has not been feasible to track the individual movement of salmon. Microchemical techniques, specifically trace element and stable isotope analyses, can be used to identify the marine migration life history of Chinook and Coho that return to their natal watersheds. Initial results on 2018 Coho samples indicate that otolith trace elements can be used to determine differences between marine regions with a 100% classification success rate. Roughly 30-40% of Coho from a few Southern BC river systems remained as residents within the Salish Sea, which is consistent with other models. Contaminants of concern, such as mercury (Hg) and polychlorinated biphenyls (PCBs) as well as dietary tracers (stable isotopes of C, N, S) are assessed in conjunction with marine migration information to determine differences in contamination between marine regions across the North Pacific.
Session Title
Poster Session 4: People Working Together to Protect the Salish Sea
Conference Track
SSE14: Posters
Conference Name
Salish Sea Ecosystem Conference (2022 : Online)
Document Type
Event
SSEC Identifier
SSE-posters-184
Start Date
27-4-2022 4:30 PM
End Date
27-4-2022 5:00 PM
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Microchemical techniques to evaluate priority contaminant sources along the migration routes of Chinook (Oncorhynchus tshawytscha) and Coho Salmon (Oncorhynchus kisutch)
During their marine life stage, Chinook (Oncorhynchus tshawytscha) and Coho Salmon (Oncorhynchus kisutch) from watersheds connected to the Salish Sea display two distinct migration phenotypes; Salish Sea resident and out-migrant. Knowledge of Chinook and Coho marine migrations has been limited to tagged individuals caught by anglers and researchers. It is unclear how fishing effort and angler compliance, as well as other factors influence the proposed migration pathways undertaken by different stocks. Amongst the migrant phenotype, these salmon may only move as far as the continental shelf just off the coast of Washington and Vancouver Island, or they may migrate offshore into the Gulf of Alaska. It is unknown how environmental and genetic factors cause some salmon to remain resident in the Salish Sea and others to out-migrate. These different migration pathways influence contaminant burden of these salmon and the degree to which they are exposed to local versus global sources. It is currently unknown which migration paths would lead to increased contaminant burdens as it has not been feasible to track the individual movement of salmon. Microchemical techniques, specifically trace element and stable isotope analyses, can be used to identify the marine migration life history of Chinook and Coho that return to their natal watersheds. Initial results on 2018 Coho samples indicate that otolith trace elements can be used to determine differences between marine regions with a 100% classification success rate. Roughly 30-40% of Coho from a few Southern BC river systems remained as residents within the Salish Sea, which is consistent with other models. Contaminants of concern, such as mercury (Hg) and polychlorinated biphenyls (PCBs) as well as dietary tracers (stable isotopes of C, N, S) are assessed in conjunction with marine migration information to determine differences in contamination between marine regions across the North Pacific.
