The broadbill swordfish (Xiphias gladius) is a worldwide fish, found in all tropical to temperate oceans. In the Pacific, swordfish range from Asia to the Americas and from northern waters off Alaska to the southern reaches of South America.
Swordfish prefer water temperatures of 64° to 72°. Juvenile fish, especially, like warm water and are found only in tropical regions. Adults have a greater temperature tolerance and range widely over the Pacific, spawning in the tropics and feeding in temperate regions.
Swordfish concentrate in areas where food is abundant, along frontal zones where ocean currents meet to create turbulence and sharp temperature breaks. The Pacific Ocean has five major frontal zones where swordfish congregate, and these are where most fishing occurs.
Swordfish abundance is related to oceanic cycles, and cycles are influenced by climatic conditions. Water temperature, availability of food, and fish migration patterns all play a role, influencing fishing success.
Swordfish are fished by many Pacific Rim countries, and fishermen use a variety of harvesting methods, including longline, drift gillnet, and harpoon. Japan, Chile, Mexico, and Peru, as well as California, employ gillnets to capture swordfish. (Both Japan and Taiwan also operate a Pacific-wide longline fishery for swordfish and tunas.)
In 1988 (the most recent year compiled) the Pacific Ocean swordfish harvest totaled 25,624 metric tons (mt), or about 56.5 million pounds, according to the Food and Agriculture Organization of the United Nations (FAO).
Scientists consider Pacific Ocean swordfish stocks to be in good condition and able to withstand increased catches. (Bartoo and Coan, 1989)
The top swordfish-harvesting nations in the Pacific in 1988:
Country Catch Japan 29.8 million pounds Chile 9.8 million pounds Philippines 8.9 million pounds USA, California 2.4 million pounds* (*dressed weight)
California's swordfish fishery has a small impact on Pacific swordfish stocks, yet California fishermen are the most strictly regulated of all Pacific Rim fleets.
In fact, swordfish is one of California's most important fisheries. California swordfish fishermen work hard, often enduring dangerous ocean conditions, to provide high-quality local swordfish for consumers.
California's Swordfish Fishery
The oldest U.S. fishery for Pacific swordfish is California's harpoon fishery. Beginning at the turn of the 20th century, fishermen wielding harpoons scanned the ocean during fair weather in summer and fall, hunting for sign of swordfish -- a pair of fins slicing the water.
Swordfish characteristically surface at night and move to the depths in daylight, but sometimes, when conditions are right, they bask at the surface. At these times the prized billfish are vulnerable to harpooners.
California's swordfish fishery grew in response to consumer demand: but harpoon catches varied widely year-to-year, influenced by oceanic cycles and the billfish's inclination to "fin." Harpoon landings peaked in 1978 at 2.6 million pounds (dressed weight). That year, swordfish were unusually abundant off California.
By 1978, pioneering gillnet fishermen, experimenting with short-length drift nets designed to catch thresher shark, discovered that large-mesh nets set at night also caught swordfish. In 1979, the Legislature authorized the incidental take of swordfish in the thresher shark fishery. In 1982, following biological studies on the gear, the Legislature passed another bill, which allowed fishermen to target swordfish with short-length drift gillnets and also limited entry to the fishery. About 200 permits were issued; most harpooners began fishing swordfish with gillnets.
Fishermen switched to short-length, large-mesh drift gillnets because of the gear's size-selectivity and efficiency in operation -- its ability to provide a consistent catch in all water conditions. This provides consumers with a steady supply of high-quality, locally-caught swordfish.
Today California driftnetters typically deploy nylon swordfish nets with a mesh size of 18 to 22 inches -- nearly as wide as an open car window. The size- selective mesh is suspended 36-75 feet underwater, which, unlike foreign high-seas drift nets, greatly reduces interactions with marine mammals and seabirds. The large mesh captures swordfish and shark, sometimes albacore, bluefin and yellowfin tuna, and when the water is right, tropical species such as opah and louvar, all prized at market. Nets are set at dusk to drift all night, attached to the boat. The catch is retrieved at dawn. Currently about 60 to 80 driftnet boats are active in California's swordfish fishery; many range up to 200 miles or more offshore, from San Francisco to the Mexican border, fishing in fair weather and foul, following ocean currents and temperature breaks in search of migrating broadbills.
California's swordfish driftnet fishery has been strictly regulated since its beginnings. Among restrictions:
California Driftnets vs. Foreign High Seas Nets