up the Yukon River. Chum fry migrate out to sea from March through July, almost immediately after becoming free swimmers. They spend one to three years traveling very long distances in the ocean. These are the last salmon to spawn (November to January) in some regions. In Alaska they are the first to spawn in June and August and are then followed by pink and coho salmon. They die about two weeks after they return to the freshwater to spawn. They utilize the lower tributaries of the watershed, tend to build nests called redds, really little more than protected depressions in the gravel, in shallow edges of the watercourse and at the tail end of deep pools. The female lays eggs in the redd, the male sprays milt on the eggs, and the female covers the eggs with gravel. The female can lay up to 4000 eggs. Diet Juvenile chum eat zooplankton and insects. Recent studies show that they also eat comb jellies. As adults, they eat smaller fish. Distribution Chum salmon have the largest natural range of any Pacific salmon. Chum are found all around the North Pacific, off the coasts of Japan, Korea, the Russian Far East, British Columbia in Canada, and from Alaska to California in the United States. They undergo the longest migrations within the genus Oncorhynchus, far up the Yukon River in Alaska and Canada, and deep into the Amur River basin in Northeast China and Russia. In lesser numbers they migrate thousands of kilometers up the Mackenzie River. In the Arctic Ocean they are found in limited numbers from the Laptev Sea to the Beaufort Sea. In North America chum salmon spawn from the Mackenzie River in the Arctic to as far south as the Umpqua River, Oregon, although they were also reported in the San Lorenzo River near Santa Cruz, California in 1915 and the Sacramento River in northern California in the 1950s. In fall 2017 a half dozen chum salmon were counted in Lagunitas Creek about north of San Francisco, California. In the open ocean, chum salmon stay fairly high on the water column, rarely diving below . Their typical swimming depths are from the surface during the day, and during the night. Commercial use and value The registered total harvest of the chum salmon in the North Pacific in 2010 was some 313,000 tons, corresponding to 91 million fish. Half of