We recommend that several (we suggest 3) deep-water moorings be placed in the Alaskan Gyre. These moorings should be located (1) off the shelf in deep water, but adjacent to the coastal region selected for detailed process studies; (2) near the center of the Alaskan Gyre; and, (3) at an intermediate location between (1) and (2). The intent is to use the data collected from these three moorings to monitor the abundance and distribution of potential salmon prey. The locations are suggested by the observations of Brodeur and Ware (1992) that zooplankton abundance increased most markedly over decadal scale periods along the margins of the Gulf of Alaska--more so than in the central Gulf. If an important feature of the decadal change observed by Brodeur and Ware is a shift in the distribution of zooplankton from the central to marginal regions of the gyre, then it is important for a U.S. GLOBEC study to include an effort to capture the transport of subarctic zooplankton to the coastal zone. Multiple moorings, spanning the central gyre to the margin, would provide the data necessary to document such shifts. The moorings should consist of mostly biological instrumentation, but with some physical observation capability. It is most important that this mooring be equipped to measure acoustic backscatter, preferably at multiple frequencies, to provide an estimate of zooplankton biomass (and perhaps size), and light and fluorescence sensors (to measure phytoplankton stocks). An appropriate bio-optical model could be used to estimate primary production from light and phytoplankton biomass estimates. In the Prince William Sound region, the three deep-water moorings would complement existing or planned moorings near Seal Rock on the shelf proper, and two moorings within PWS.
Ships of opportunity should be used to expand geographic coverage in the Alaskan gyre beyond that of the mooring locations. For example, it was noted at the workshop that ships routinely cross the gyre enroute from Valdez, AK to Hawaii. This would be a valuable route for towing a high-speed undulating instrument. There may be other routes as well.