Project Title:    GLOBEC 2000 - A long-term observation program using natural stable isotope
                         abundance for detecting coastal Gulf of Alaska zooplankton source fluctuations
                         in fishes.

Staff:

Summary description:
Decadal-scale changes in the production cycles of the sub-Arctic Pacific Ocean have been conjectured to effect population changes in fishes via their zooplankton forage base. Zooplankton populations occurring near the Gulf of Alaska continental shelf break appear to undergo dramatic oscillations in abundance over decadal time scales. These consist principally of inter-zonal (because life-history stages span shallow- and deep-water zones) zooplankton (primarily Neocalanus copepods) stocks that are driven onto the shelf providing the ecosystem with an important forage base.

The data from this project will enable the assessment of seasonal (during 2001 and 2003) and inter-annual nitrogen and carbon variability of large-bodied zooplankton across the Gulf of Alaska continental shelf during their peak occurrence in spring and summer each year, that will be matched to analogous measurements for juvenile pink salmon and other fishes. These data will be used to isotopically characterize coastal and oceanic (offshore) organic carbon sources and their utilization by fishes. Isotopic shifts in fishes and diapausing copepods are expected to shift in synchrony varying proportionately with the intensity of cross-shelf transport.

This project will augment and complement existing and continuing core LTOP observations being made along the Seward Line transect and select stations near and in Prince William Sound. Samples that were acquired by T. Kline from fall 1997 through summer 2000 on pilot LTOP project (Weingartner, Principal Investigator) cruises will be analyzed for carbon and nitrogen isotopes as part of this project during FY01 and FY02. Additional samples will be collected and analyzed as part of this project from 2001 through 2005.

The data will also be used to validate the tacit assumption in Northeast Pacific GLOBEC restrospective studies that nitrogen values of lower food chain biota are constant so that changing values can be interpreted to reflect varying food chain length or salmon run size.

Thomas C. Kline, Jr., Ph.D.,
\Principal Investigator

Signe Baumann, Project Technician

Expected results or products: This project seeks to provide the data that will link secondary production sources (zooplankton) with fish production by matching isotopic signatures of fishes with those of potential pelagic organic carbon sources.
Timeline:  Project began in June 2001 and will continue through FY05
Project budget:  $128,267 in FY01 - Projected future budgets FY02: $137,689; FY03: $139,200; FY04: $135,348; FY05 $109,55
Funding source:  National Science Foundation