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Facts In Brief

SWORDFISH

Biology:

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.

The Fishery:

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

History:

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.

Fishery Operation:

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.

Regulations:

California's swordfish driftnet fishery has been strictly regulated since its beginnings. Among restrictions:

  • Drift nets were limited to 6,000 feet (one nautical mile) in length; minimum mesh size was set at 14 inches. Swordfish fishermen typically use 18-20 inch mesh nets.
  • Areas were set aside for harpooners only; and extensive areas were closed to protect marine mammals. The fishery is closed within 25 miles of the mainland December through January to protect migrating gray whales.
  • Legislation effective in 1990 prohibits driftnetting for swordfish or thresher shark within 75 miles of the mainland from February 1 through July 14 to conserve the thresher shark resource.
  • The Marine Mammal Protection Act mandated observer coverage on driftnet vessels since 1989.
  • In the fall of 1997, accoustic "pingers" were mandated for use on all swordfish and shark driftnets fishing in California-Oregon waters. This rule followed the first year of a test of the effectiveness of pingers in reducing interactions with marine mammals. The study, funded in part by California swordfish fishermen and carried out and monitored by federal observers, successfully reduced interactions with cetaceans by 75 percent. The use of pingers is helping California's swordfish fleet meet the stringent requirements of the Marine Mammal Protection Act to reduce interactions to rate near zero.

The Differences:

California Driftnets vs. Foreign High Seas Nets

  • California driftnets are highly visible multi-strand braided nylon twine with mesh size of 18-22"; foreign high-seas squid nets are single-strand monofilament, with mesh sized 4", virtually invisible underwater.
  • California net length is considered "small-scale," 1 mile or less.
  • U.N. and Congressional resolutions pertain to "large-scale" foreign high-seas nets, over 1 1/2 miles in length.
  • California nets are usually suspended 36-75 feet under-water, which greatly minimizes interactions with marine mammals and seabirds.
  • Foreign nets drift on the surface, where most marine mammal and seabird entanglement occurs.
  • Acoustic pingers are deployed on all California swordfish-shark driftnets.
  • Observer reports indicate that California's driftnet fishery has a minimal impact on sealife.