Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.

Historically, salmon stocks from the Columbia River and Snake River formed one of the most valuable fisheries on the west coast of North America. However, salmon and steelhead returns sharply declined during the 1980s and 1990s to reach nearly 1 million fish. Although several factors may be responsi...

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Main Authors: Trudel, Marc, Tucker, Strahan, Morris, John
Other Authors: United States. Department of Energy.
Format: Report
Language:English
Published: United States. Bonneville Power Administration. 2009
Subjects:
Online Access:https://doi.org/10.2172/962202
http://digital.library.unt.edu/ark:/67531/metadc931500/
id ftunivnotexas:info:ark/67531/metadc931500
record_format openpolar
institution Open Polar
collection University of North Texas: UNT Digital Library
op_collection_id ftunivnotexas
language English
topic Biomass
Salmon
Columbia River
Columbia River Basin
Mitigation
Food Chains
Feeding
Copepods
Phytoplankton
Nutrients
Fisheries
Life Cycle
Climates
Plankton
13 Hydro Energy
Zooplankton
High Seas
spellingShingle Biomass
Salmon
Columbia River
Columbia River Basin
Mitigation
Food Chains
Feeding
Copepods
Phytoplankton
Nutrients
Fisheries
Life Cycle
Climates
Plankton
13 Hydro Energy
Zooplankton
High Seas
Trudel, Marc
Tucker, Strahan
Morris, John
Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.
topic_facet Biomass
Salmon
Columbia River
Columbia River Basin
Mitigation
Food Chains
Feeding
Copepods
Phytoplankton
Nutrients
Fisheries
Life Cycle
Climates
Plankton
13 Hydro Energy
Zooplankton
High Seas
description Historically, salmon stocks from the Columbia River and Snake River formed one of the most valuable fisheries on the west coast of North America. However, salmon and steelhead returns sharply declined during the 1980s and 1990s to reach nearly 1 million fish. Although several factors may be responsible for the decline of Columbia River salmon and steelhead, there is increasing evidence that these drastic declines were primarily attributable to persistently unfavorable ocean conditions. Hence, an understanding of the effects of ocean conditions on salmon production is required to forecast the return of salmon to the Columbia River basin and to assess the efficacy of mitigation measures such as flow regulation on salmon resources in this system. The Canadian Program on High Seas Salmon has been collecting juvenile salmon and oceanographic data off the west coast of British Columbia and Southeast Alaska since 1998 to assess the effects of ocean conditions on the distribution, migration, growth, and survival of Pacific salmon. Here, we present a summary of the work conducted as part of the Canada-USA Salmon Shelf Survival Study during the 2008 fiscal year and compare these results with those obtained from previous years. The working hypothesis of this research is that fast growth enhances the marine survival of salmon, either because fast growing fish quickly reach a size that is sufficient to successfully avoid predators, or because they accumulate enough energy reserves to better survive their first winter at sea, a period generally considered critical in the life cycle of salmon. Sea surface temperature decreased from FY05 to FY08, whereas, the summer biomass of phytoplankton increased steadily off the west coast of Vancouver Island from FY05 to FY08. As in FY07, zooplankton biomass was generally above average off the west coast of Vancouver Island in FY08. Interestingly, phytoplankton and zooplankton biomass were higher in FY08 than was expected from the observed nutrient concentration that year. This suggests nutrients were more effectively by phytoplankton in FY08. In addition, the abundance of lipid-rich northern copepods increased from FY05 to FY08, whereas lipid-poor southern copepods showed the opposite pattern, suggesting that growth conditions were more favorable to juvenile salmon in FY08 than in previous years. However, growth indices for juvenile coho salmon were near the 1998-2008 average, both off the west coast of Vancouver Island and Southeast Alaska, indicating that additional factors beside prey quality affect juvenile salmon growth in the marine environment. Catches of juvenile Chinook, sockeye and chum salmon off the west coast of Vancouver Island in June-July 2008 were the highest on record during summer since 1998, suggesting that early marine survival for the 2008 smolt year was high. Interestingly, the proportion of hatchery fish was high (80-100%) among the juvenile Columbia River Chinook salmon caught off the British Columbia coast during summer, suggest that relatively few wild Chinook salmon are produced in the Columbia River Chinook. In addition, we also recovered two coded-wire tagged juvenile Redfish Lake sockeye salmon in June 2008 off the west coast of British Columbia. As relatively few Redfish Lake sockeye smolts are tagged each year, this also suggests that early marine survival was high for these fish, and may result in a high return in 2009 if they mature at age three, or in 2010 if they mature at age four. To date, our research shows that different populations of Columbia River salmon move to different locations along the coastal zone where they establish their ocean feeding grounds and overwinter. We further show that ocean conditions experienced by juvenile Columbia River salmon vary among regions of the coast, with higher plankton productivity and temperatures off the west coast of Vancouver Island than in Southeast Alaska. Hence, different stocks of juvenile salmon originating from the Columbia River and Snake River are exposed to different ocean conditions and may respond differently to climate changes. In particular, our work shows that the growth and fat content of Chinook and coho salmon vary along different parts of the coast and among years. These growth differences appear to be associated with differences in prey quality rather than by a direct effect of temperature on salmon growth or prey quantity, indicating that changes in ocean conditions and circulation affect salmon production indirectly through changes in prey community composition and quality. Taken together, our analyses indicate that the relative survival of different stocks of salmon in the ocean will depend on where they migrate in the ocean, and that changes at the base of the food chain must be taken into consideration to understand the effects of ocean conditions on salmon growth, and hence, on salmon survival.
author2 United States. Department of Energy.
format Report
author Trudel, Marc
Tucker, Strahan
Morris, John
author_facet Trudel, Marc
Tucker, Strahan
Morris, John
author_sort Trudel, Marc
title Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.
title_short Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.
title_full Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.
title_fullStr Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.
title_full_unstemmed Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report.
title_sort canada-usa salmon shelf survival study, 2007-2008 annual report.
publisher United States. Bonneville Power Administration.
publishDate 2009
url https://doi.org/10.2172/962202
http://digital.library.unt.edu/ark:/67531/metadc931500/
long_lat ENVELOPE(-125.003,-125.003,54.000,54.000)
ENVELOPE(-130.143,-130.143,54.160,54.160)
geographic British Columbia
Canada
Pacific
Sockeye
geographic_facet British Columbia
Canada
Pacific
Sockeye
genre Alaska
Copepods
genre_facet Alaska
Copepods
op_relation rep-no: P110730
grantno: 39197
doi:10.2172/962202
osti: 962202
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spelling ftunivnotexas:info:ark/67531/metadc931500 2023-05-15T18:48:59+02:00 Canada-USA Salmon Shelf Survival Study, 2007-2008 Annual Report. Trudel, Marc Tucker, Strahan Morris, John United States. Department of Energy. 2009-03-09 109 pages Text https://doi.org/10.2172/962202 http://digital.library.unt.edu/ark:/67531/metadc931500/ English eng United States. Bonneville Power Administration. rep-no: P110730 grantno: 39197 doi:10.2172/962202 osti: 962202 http://digital.library.unt.edu/ark:/67531/metadc931500/ ark: ark:/67531/metadc931500 Biomass Salmon Columbia River Columbia River Basin Mitigation Food Chains Feeding Copepods Phytoplankton Nutrients Fisheries Life Cycle Climates Plankton 13 Hydro Energy Zooplankton High Seas Report 2009 ftunivnotexas https://doi.org/10.2172/962202 2016-11-26T23:11:40Z Historically, salmon stocks from the Columbia River and Snake River formed one of the most valuable fisheries on the west coast of North America. However, salmon and steelhead returns sharply declined during the 1980s and 1990s to reach nearly 1 million fish. Although several factors may be responsible for the decline of Columbia River salmon and steelhead, there is increasing evidence that these drastic declines were primarily attributable to persistently unfavorable ocean conditions. Hence, an understanding of the effects of ocean conditions on salmon production is required to forecast the return of salmon to the Columbia River basin and to assess the efficacy of mitigation measures such as flow regulation on salmon resources in this system. The Canadian Program on High Seas Salmon has been collecting juvenile salmon and oceanographic data off the west coast of British Columbia and Southeast Alaska since 1998 to assess the effects of ocean conditions on the distribution, migration, growth, and survival of Pacific salmon. Here, we present a summary of the work conducted as part of the Canada-USA Salmon Shelf Survival Study during the 2008 fiscal year and compare these results with those obtained from previous years. The working hypothesis of this research is that fast growth enhances the marine survival of salmon, either because fast growing fish quickly reach a size that is sufficient to successfully avoid predators, or because they accumulate enough energy reserves to better survive their first winter at sea, a period generally considered critical in the life cycle of salmon. Sea surface temperature decreased from FY05 to FY08, whereas, the summer biomass of phytoplankton increased steadily off the west coast of Vancouver Island from FY05 to FY08. As in FY07, zooplankton biomass was generally above average off the west coast of Vancouver Island in FY08. Interestingly, phytoplankton and zooplankton biomass were higher in FY08 than was expected from the observed nutrient concentration that year. This suggests nutrients were more effectively by phytoplankton in FY08. In addition, the abundance of lipid-rich northern copepods increased from FY05 to FY08, whereas lipid-poor southern copepods showed the opposite pattern, suggesting that growth conditions were more favorable to juvenile salmon in FY08 than in previous years. However, growth indices for juvenile coho salmon were near the 1998-2008 average, both off the west coast of Vancouver Island and Southeast Alaska, indicating that additional factors beside prey quality affect juvenile salmon growth in the marine environment. Catches of juvenile Chinook, sockeye and chum salmon off the west coast of Vancouver Island in June-July 2008 were the highest on record during summer since 1998, suggesting that early marine survival for the 2008 smolt year was high. Interestingly, the proportion of hatchery fish was high (80-100%) among the juvenile Columbia River Chinook salmon caught off the British Columbia coast during summer, suggest that relatively few wild Chinook salmon are produced in the Columbia River Chinook. In addition, we also recovered two coded-wire tagged juvenile Redfish Lake sockeye salmon in June 2008 off the west coast of British Columbia. As relatively few Redfish Lake sockeye smolts are tagged each year, this also suggests that early marine survival was high for these fish, and may result in a high return in 2009 if they mature at age three, or in 2010 if they mature at age four. To date, our research shows that different populations of Columbia River salmon move to different locations along the coastal zone where they establish their ocean feeding grounds and overwinter. We further show that ocean conditions experienced by juvenile Columbia River salmon vary among regions of the coast, with higher plankton productivity and temperatures off the west coast of Vancouver Island than in Southeast Alaska. Hence, different stocks of juvenile salmon originating from the Columbia River and Snake River are exposed to different ocean conditions and may respond differently to climate changes. In particular, our work shows that the growth and fat content of Chinook and coho salmon vary along different parts of the coast and among years. These growth differences appear to be associated with differences in prey quality rather than by a direct effect of temperature on salmon growth or prey quantity, indicating that changes in ocean conditions and circulation affect salmon production indirectly through changes in prey community composition and quality. Taken together, our analyses indicate that the relative survival of different stocks of salmon in the ocean will depend on where they migrate in the ocean, and that changes at the base of the food chain must be taken into consideration to understand the effects of ocean conditions on salmon growth, and hence, on salmon survival. Report Alaska Copepods University of North Texas: UNT Digital Library British Columbia ENVELOPE(-125.003,-125.003,54.000,54.000) Canada Pacific Sockeye ENVELOPE(-130.143,-130.143,54.160,54.160)