The dams create vast reservoirs that make it possible for Lewiston, Idaho, 450 miles from the Pacific Ocean, to operate as the farthest inland seaport on the West Coast. Critics say the dams kill vast numbers of salmon and steelhead, and do not provide enough benefits to compensate for the losses of those iconic fish. A coalition of environmentalists, Indian tribes and outdoor enthusiasts want Lower Granite, Little Goose, Lower Monumental and Ice Harbor dams breached. Killer whales in the Pacific Ocean depend on chinook salmon as a mainstay of their diets, and would be helped if the dams were breached, said Deborah Giles of the Southern Resident Killer Whale Chinook Salmon Initiative. Opponents contend that the shipping traffic made possible by the dams is in sharp decline and that the hydropower produced by the dams can be replaced with alternative energy resources. The Snake River dams are equipped with sophisticated fish ladders that allow returning salmon to reach spawning grounds.