Purse seines lead in quantity of fish landed by U.S. fishermen. The purse line,
when drawn to the vessel, effectively prevents the fish from escaping under the
net. Purse seines are used to catch schooling fish like tuna, menhaden, and
salmon. Tuna purse seines (one is shown) are of enormous size, and may be 3/4
mile long, 200 ft. deep, weight 15 tons, and have 10,000 floats.