"Food was a constant concern for the drivers of Alaska. The dogs' diet had to include enough protein and fat to keep them healthy and warm for winter travel, and the drivers needed to stock huge quantities. The most common food source was salmon. A musher would build fish traps out of wood and wire and lay them out in the river to catch the salmon runs.* Then he would cut up the fish and hang them out to dry on racks. The job could take a whole summer; each year the driver would stock about 5,000 pounds of the vitamin-rich meat.
* Many of the drivers used a fish wheel, which had two baskets attached to a long wooden axle. As the wheel turned in the current of the river, migrating fish were scooped up by the baskets and dropped down a ramp that led into a compartment. The fish wheel was held in place by an anchor on shore or by posts driven into the riverbed."
--Gay Salisbury and Laney Salisbury, The Cruelest Miles: The Heroic Story of Dogs and Men in a Race against an Epidemic (NY and London: W.W. Norton & Co., 2003), 61