In the ocean, the young salmon travel long distances away from the Chobe River and only return to this area when they are ready to spawn. These details are summarized in Figure 3 . Two other species of salmon inhabit the Chobe River drainage. These are the pink salmon and the coho salmon. The pink and the coho salmon lay their eggs in the same breeding sites as the sockeye salmon and their young grow in the same lake before leaving for the sea.
Nothing is known about the fish which the sockeye encounter in the ocean.
Eggs and small fish living in the lakes and streams of this region are eaten by many species of fish, such as coho salmon, steelhead, sculpins, Dolly Varden trout, the three-spined stickleback, and alpine char. Birds such as the common merganser, terns, ducks, gulls, and loons also commonly eat small fish. Bears catch adult salmon as they migrate up the streams on their way to spawning areas. Nothing is known about the sockeye's sojourn in the ocean except that they are caught by fishermen at the mouth of the river when they return on their spawning run. Determine what factors might influence the size of the salmon population and decide what specific information you need to evaluate the importance of each factor.