Sea Grant Project Progress Report
Updated
22 October 2001
|
| Project Title: |
Long-Term Variability in Alaskan Sockeye
Salmon, Part 2: Effects of Past Warm Climate on Salmon Abundance
|
| Project Number: |
R/31-05 |
Initiation Date: |
02/01/00 |
| Revision Date: |
|
Completion Date: |
07/31/03 |
| Principal Investigator: |
Bruce
Finney |
| Affiliation: |
Institute of Marine Science, SFOS/UAF |
| Sea Grant Funds: |
$84,362 |
| Match Funds: |
$0 |
| Related Projects: |
|
| Parent Projects: |
R/07-22
Long-Term Variability in Alaskan Sockeye Salmon Abundance |
| Keywords: |
Pacific salmon, fisheries variability, paleoceanography,
paleoclimatology |
| 1. Objectives: |
To apply methodologies that have been developed
for reconstructing past changes in sockeye salmon escapement from
sediment core analysis of Alaskan sockeye salmon nursery lakes.
More specifically, to determine past variability in sockeye abundance
and associated aquatic environment in four lakes at high-resolution
(< 10 years) during the past approximately 2000 years. To determine
the nature of salmon return fluctuations prior to start of commercial
fishing and characterize any cyclic behavior through time-series
analysis. To develop measures or indices to help predict future
salmon escapements. |
| 2. Rationale: |
Fisheries managers need information
on long-term changes in population variability in order to determine
the factors that control this variability. Such information can
help delineate changes caused by natural processes and those caused
by man. This information, in turn, is necessary to predict future
trends and wisely manage the resource. Because the historical database
is relatively short and incomplete, it is necessary to study proxy
records such as can be found in sediment cores. |
| 3. Methodology: |
Sediment cores have or will
be collected in selected nursery lakes and sampled at high-resolution
(< 10 years). Chronologies will be determined by tephrochronology
and 14C dating. Hindcasts of salmon-run strength will
be based on changes in marine-derived nitrogen determined by analysis
of delta 15N. |
4. Benefits:
|
This project should benefit
fisheries managers, as information on the nature of population fluctuation
is necessary for proper management. Managers need to predict how
populations will fluctuate in response to natural and anthropogenic
environmental changes, such as temperature change, El Niño–Southern
Oscillation events, and artificial fertilization. Commercial and
recreational fishers will benefit as well, as this information will
help aid wise management and maintenance of the resource. |
5. Accomplishments:
|
October 2000:
The principal investigator has recent experience in paleolimnological
reconstructions and in the use of stable isotopes. Recent sediment
studies on Alaskan sockeye lakes have refined the methods that
will be used as part of this study and determined criteria to
select systems that are most likely to be suitable for these methods.
Several papers on these studies have been published; see R/07-22.
October 2001:
Significant progress has been made in the field, laboratory,
and manuscript preparation. The fieldwork for this project is
now complete as additional high-quality cores were collected from
Becharof and Ugashik Lakes. Lab analysis is complete for some
sites, and in progress in others. A synthesis manuscript is in
review in Nature. An invited talk was presented at the
American Fisheries Society National Meeting in Phoenix, Aug. 2001,
at the special climate change and fisheries symposium.
|
| 6. Publications and Presentations: |
Finney, B.P., I. Gregory-Eaves, M.S.V. Douglas, and J.P. Smol.
In review. Pronounced and synchronous variability in sockeye salmon,
sardines, and anchovies from the Northeast Pacific over the past
2000 years. Nature, in review Aug. 2001.
Finney, B.P. 2001. A long-term view on relationships between
Pacific salmon abundance and climatic change. Invited talk at
Special Symposium on Climate Change and Fisheries, American Fisheries
Society National Meeting, Aug. 2001, Phoenix, AZ.
Finney, B.P., I. Gregory-Eaves, J. Sweetman, M.S.V. Douglas,
and J.P. Smol. 2000. Impacts of climatic change and fishing on
Pacific salmon abundance over the past 300 years. Science 290:795-799.
Climate
change, fishing, alter salmon abundance (Alaska Sea Grant
news release)
Why Salmon
Boom, Then Bust (Arctic Science Journeys Radio)
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| 7. Students Supported: |
Jon Sweetman. Defended MS thesis
April 2001, Graduated Dec. 2001. Title: Factors influencing zooplankton
populations in Alaskan sockeye salmon (Oncorhynchus nerka) nursery
lakes: Insights from limnological and paleolimnological analyses. |
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