Sport fishing for striped marlin (Tetrapturus audax) began off southern California in 1903. Catches of this species have fluctuated widely. Some of the annual variation in catch (15% to 25%) may be attributable to variations in water temperatures. When the marlin season ends in southern California, usually in November, some fishermen who own yachts begin fishing for billfish in Mexican waters, particularly near Cabo San Lucas and La Paz, Baja California. This fishing is restricted to winter and spring because of severe tropical storms which occur in the summer, and lack of protective harbors except at La Paz.