(continued)

Lake Clark is the 6th largest freshwater lake in Alaska and drains a watershed of 9600 km². It is approximately 74 km long, 3 to 8 km wide, and has a total surface area of 267 km². It averages 103 meters in depth with a maximum depth of over 300 m. Because the lake is fed by glaciers, it is cold and extremely turbid in the upper watershed, becoming less so towards the outlet into the Newhalen River (see map). Little information on aquatic species and their dynamics exists for this watershed.

Sockeye salmon are a cornerstone species throughout Bristol Bay lake systems. Sockeye salmon home from oceanic feeding grounds to natal freshwaters to spawn and then die. This behavior transports millions of tons of nutrients from the rich marine environment to Alaska’s nutrient poor freshwaters. This annual nutrient influx links the aquatic and terrestrial environments increasing production at all levels of the food chain. Nutrients from spawned-out salmon carcasses play a crucial role in sustaining the productivity of riparian and lacustrine ecosystems, including the perpetuation of future salmon runs. Salmon have a major influence on the summer and fall distribution and abundance of species that prey on them, including birds, mammals, and fish. Lake trout, rainbow trout, and burbot all derive nutrients from sockeye salmon in one form or another. Because much of Lake Clark remains ice free until February, salmon carcasses support overwintering bald eagles and are an important food resource for an array of terrestrial predators and scavengers including bears, wolves, coyotes, red fox, wolverine and lynx.

(continued to page 3 of the Overview)