Glacier Bay small schooling fish and marine ecosystem project. Glacier Bay is an ecosystem characterized by change. The Little Ice Age glacial advance of about 80 km and its subsequent rapid retreat over the past 200 years are the largest glacial fluctuations of historic record. Both the physical and biological characteristics of Glacier Bay have shown sensitivity to climate change. The causes of glacial destabilization are not well documented, although most workers infer that it was caused by global warming. With glacial fluctuation, habitats and ecosystems can change dramatically. Advancing glaciers cover habitat and increase ice proximal sediment and freshwater discharges. Retreating glaciers expose new areas but these new habitats are composed of unstable substrates, subject to rapid changes. The volume of freshwater entering the Bay changes markedly as glaciers advance and retreat, modifying salinity and water column structure. Increased freshwater discharge influences estuarine circulation processes, as well as nutrient influx. All of these factors result in a high variation in the location and amount of primary production, which in turn affects food webs in both the marine and terrestrial ecosystems. Glacier Bay, Alaska, provides an excellent opportunity to utilize both the biological and physical sciences to address resource issues in federal waters. Glacier Bay National Park is the site of intense controversy regarding commercial fishing and vessel management. Unique research opportunities exist for several reasons: 1) the Bay exhibits high spatial variability in oceanographic, sedimentary, and successional processes along the glacial chronosequence; 2) there is a pattern of presence and absence of key species that allows testing of ecological relationships; and 3) new legislation will close parts of the Park making it possible to compare ecosystem processes in fished vs. unfished areas.