U.S.-GLOBEC: NEP Phase IIIb-CGOA: Environmental influences on growth and survival of Southeast Alaska coho salmon in contrast with other Northeast Pacific regions
L. Botsford, A. Hastings [Both at Univ. Calif. Davis], N. Bond [University of Washington], H. Batchelder [Oregon State University], A. Wertheimer [NOAA Alaska Fisheries Science Center], M. Adkinson [University of Alaska Fairbanks]

Project Summary

Intellectual Merit - GLOBEC NEP's program of field sampling, retrospective analysis and modeling, even with a strong comparative component and observation of an environmental shift in 1999/2000, has not achieved a predictive understanding of salmon abundance. We can describe the physical/biological conditions associated with: (1) annual temporal variability in ocean survival, and (2) the spatial distribution of juveniles, but we have not linked those two, nor do we understand the mechanisms that underlie them. Here we propose to achieve such an understanding and predictability by taking advantage of the comparative approach, synthesizing several sources of information on a species, coho salmon, Oncorhynchus kisutch, which: (a) was studied by GLOBEC in both Southeast Alaska (SEAK) and the California Current System (CCS), and (b) covaries inversely in these two systems. We will describe the biological/physical conditions under which juvenile coho salmon were found in GLOBEC NEP-funded studies in SEAK, and describe how that juvenile salmon habitat varied over 8 years at one location and 4 years at another. We will then employ an individual-based model to assess the advantages of these habitats to growth and mortality of juvenile coho salmon, and to describe how individual salmon could interact with such spatial distributions. We will extend the findings of a GLOBEC-NEP funded retrospective study, that ocean survivals of an SEAK stock depended positively on abundance of hatchery-released congeners, to assess how common such a potential predator buffering effect might be. To study the response of individual stocks along the coast north of the bifurcation of the West Wind Drift (WWD), we will need to develop local indicators of biologically important physical conditions, based on local winds and general circulation. To compare SEAK findings across the NEP, we will not only compare our results with similar ongoing studies in the CCS, but will also use the coded wire tag data set, which spans both systems, to seek a model of coho salmon early life history that is consistent across the two systems, but can have different physical forcing in each.

Broader Impacts - The ultimate product of this project will be an indicator of annual ocean conditions, as they affect salmon survival and age of spawning. These conditions would likely vary spatially from the CCS to Alaska. Such an indicator will be directly useful in the short term in fishery management. Perhaps more important from a societal view, this indicator of ocean conditions will also be useful in the long term to reduce the uncertainty and contentiousness surrounding management of factors influencing the freshwater phase of the salmon lifecycle, such as dams, water diversions, and habitat destruction.

NSF Award Summary

None available.

This page was last updated on March 14, 2007.

Maintained by:
Hal Batchelder
College of Oceanic and Atmospheric Sciences
Oregon State University
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