The Seward Line is a series of stations along a 150 nautical mile long transect, starting with the GAK1 location near the entrance of Resurrection Bay on the eastern side of the Kenai Peninsula in southcentral Alaska. This transect stretches from GAK1 into oceanic waters well past the continental shelf break. Data from this transect have been critical in defining the oceanic current systems that characterize the system.
The Seward Line complements the other NGA LTER transects: the Kodiak Island Line, Middleton Island Line, and Cape Suckling Line. Additional sampling locations are located in western Prince William Sound.
UAF oceanography professor Dr. Thomas C. Royer established the Seward Line and GAK1 in December, 1970. Dr. Royer continued sampling over the years, and starting in fall 1997, sampling in the NGA area expanded to include chemistry and biology during 6-7 cruises per year as part of the U.S. Global Ocean Ecosystem Dynamics (GLOBEC) program. This sampling was continued from 2005-2009 by the North Pacific Research Board with reduction to two cruises annually. This program is now funded by a consortium of NPRB, AOOS, EVOS and most recently NSF.
The Seward Line cruises on the Gulf of Alaska shelf determine the physical and chemical oceanographic structure, the primary production and the distribution and abundance of zooplankton. The seasonal and inter-annual variations in these measurements are examined, and the results distributed to the NOAA Fisheries for inclusion in Gulf of Alaska Ecosystem Status Reports. At present, cruises are conducted each spring (May), early summer (June/July) and late summer (mid September).