Ecosystem Monitoring and Analysis (EMA)
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Mean body length of male age 4 chum salmon at Fish Creek near Hyder in Alaska from 1972 to 2006. |
Ecosystem Monitoring and Analysis research is used to develop
indicators for ecosystem dynamics, assessment, and forecasting through
monitoring changes in age and size of salmon populations and retrospective
studies to assess past changes in Gulf of Alaska and Bering Sea
salmon. Age and growth research is focused on constructing and analyzing
time series on age, size, growth, survival, and production of salmon
stocks and characterizing linkages with climate and abundance.
Monitoring Age and Size
Long-term monitoring of changes in age and size-at-maturity of Pacific salmon has occurred since the late 1950s. Annual stream surveys consist of the field sampling of scales, length, and weights from the carcasses of chum salmon that spawned and died in rivers ranging from southcentral Alaska to Washington. Long-term monitoring of salmon age and size-at-maturity is used to evaluate the influence of marine climate and population abundances on the dynamics of salmon and marine fish populations.
Retrospective Studies
Seasonal and annual growth patterns of scales in relation to climate
indices and population abundances provide useful indicators for
climate change and carrying capacity limits for salmon in the North
Pacific Ocean and Bering Sea. Historic collections of salmon scales
are used to reconstruct somatic growth histories of salmon. OCC
scientists have developed and analyzed time series of growth for
Karluk, Kvichak, Egegik, and Ugashik sockeye salmon stocks.
Auke Bay Climatological Series
Environmental monitoring and assessment requires long term consistent
observations of climatological and physical environmental data.
Daily environmental records have been maintained at the Auke Bay
Marine Station since February 1963 as part of the National Weather
Service Cooperative Observer Program. Additional historical records
extend back to 1959 prior to the establishment of the U. S. Fish
and Wildlife Service Bureau of Commercial Fisheries.
Southeast Alaska Coastal Monitoring (SECM)
The marine water of Southeast Alaska support major fisheries for
salmonid and non-salmonid fishes. The Southeast Alaska Coastal Monitoring
Program was established in 1997 to
study biological and physical environmental conditions along major
migratory corridors of juvenile salmon, in particular chum (Oncorhynchus
keta) and pink (Oncorhynchus gorbuscha) during their
spring and summer migration to the open Gulf of Alaska. Monthly
cruises during May through August track the growth and survival
of wild and hatchery stocks with particular emphasis on forage conditions.
Population Mixture Analysis (PMA)
Population mixture analysis (PMA) research by OCC is focused on
developing and improving statistical approaches for identifying
population structure and estimating population composition in fisheries
that exploit fish from multiple populations. Software developed
and maintained by OCC staff are used for research and management
of mixed fisheries.
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