Swordfish

views updated May 08 2018

Swordfish


The swordfish, Xiphias gladius, is classified in a family by itself, the Xiphiidae. This family is part of the Scombroidea, a subfamily of marine fishes that includes tuna and mackerel.

Tuna and mackerel are two of the fastest-swimming creatures in the ocean. Swordfish rival them, as well as mako sharks , with their ability to reach speeds approaching 60 mph (96.5 kph) in short bursts. Their streamlined form and powerful build account for their speed, as well as the fact that their torpedo-shaped body is scaleless and smooth, thus decreasing surface drag. Swordfish have a tall, sickle-shaped dorsal fin that cuts through the water like a knife, and their long pectoral fins, set low on their sides, are held tightly against their body while swimming. Swordfish lack pelvic fins, and they have reduced second dorsal and anal fins which are set far back on the body, adding to the streamlining. It has been suggested that their characteristic "sword"a broad, flat, beak-like projection of the upper jawis the ultimate in streamlining. The shape of their bill is one of the characteristics that separates them from the true billfish, which include sailfish and marlin.

Swordfish live in temperate and tropical oceans and are particularly abundant between 30 and 45 degrees north latitude. They are only found in colder waters during the summer months. Although fish in general are cold-blooded vertebrates, swordfish and many of their scombroid relatives are warm-blooded, at least during strenuous activity, when their blood will be several degrees higher than the surrounding waters. Another physiological adaptation is an increased surface area of the gills, which provides for additional oxygen transfer and thus allows swordfish to swim faster and longer than other species of comparable size.

Swordfish are valuable for both sport fishing and commercial fishing . The size of swordfish taken commercially is usually under 250 lb (114 kg), but some individuals have been caught that weigh over 1,000 lb (455 kg). The seasonal migration of this species has meant that winter catches are limited, but long-lining in deep waters off the Atlantic coast of the United States has proven somewhat successful in that season.

Swordfish have only become popular as food over the past 50 years. Their overall commercial importance was reduced in the 1970s, however, when relatively high levels of mercury were discovered in their flesh. Because of this discovery, restrictions were placed on their sale in the United States, which had a negative effect on the fishery. Mercury contamination was thought to be solely the result of dramatic increase in industrial pollution , but recent studies have shown that high levels of mercury were present in museum specimens collected many years ago. Although still a critical environmental and health concern, industrial sources of mercury contamination have apparently only added to levels from natural sources. Today, swordfish is considered somewhat of a luxury food item, sold at fine dining establishments.

Like any delicacy, swordfish entrees catch a tasty price for the establishments that serve them, but at what cost to the environment ?In 1999 alone, global fisheries caught roughly 55,000 tons of swordfish. About 40% of the all swordfish caught comes from the Pacific Ocean. California fisheries account for about 10% of the Pacific proportion netted each year. As mentioned, until the middle of this century, most of the swordfish caught were relatively large in size. By 1995, however, about 58% of the Atlantic swordfish caught were immature, weighing less than half the average adult mass. Juvenile fish are now caught more frequently because fishing techniques have become very efficient, leading to overfishing .

According to the Natural Resources Defense Council , an active conservation organization, two-thirds of the swordfish caught by United States fishermen are juvenile. In 1963, the average weight of swordfish caught was 250 lb (114 kg). The average weight of swordfish caught in 1999 was 90 lb (41 kg). Among conservation scientists, it is generally agreed that the minimum weight a female swordfish must attain for reproductive success is roughly 150 lb (68 kg). Standards set by the International Commission for the Conservation of Atlantic Tunas (ICCAT), however, set a minimum weight limit at 50 lb (23 kg), well below reproductive weight. The ICCAT, a regulatory council consisting of 36 nations that governs global swordfish and tuna fish catches, has limited overfishing by setting quotas for its member countries. Unfortunately, scientists believe that swordfish populations are still in danger because most swordfish are not reaching reproductive age before being caught.

Government agencies have warned fisheries that swordfish populations are in danger. The United States Marine Fisheries Service reports that the global swordfish numbers have decreased by 70% since the 1960s. Also, it is believed that if the present rate of decline continues, swordfish will become commercially extinct (too few in number to be profitable) within a decade. Despite this, excessive catching of swordfish remains a problem. In an effort to limit the rate and extent of swordfish decline, a boycott and marine conservation campaign was launched. In 1998, the swordfish became the official symbol of global overfishing for the National Coalition for Marine Conservation, representing dozens of endangered species . That year, environmental organizations such as the Natural Resource Conservation Council and Seaweb created a partnership with prominent chefs at famous fine dining establishments across the nation. Participating restaurants, leading the boycott, removed swordfish from their menus while the environmental awareness groups spread the word about swordfish decline. Restaurants in Dallas, Philadelphia, Boston, New York City, and Baltimore were among the cities that led the boycott.

Resteraunts also took swordfish off the menu due to high levels of mercury. The Food and Drug Administration has set the level of 1 part per million (ppm), but some samples of swordfish have come up as triple that regulated amount. Due to these large amounts, the FDA recommends that women who are or may become pregnant and small children avoid eating swordfish. Although it is too soon to tell, this may have a large impact on the current status of the fish.

In 1999, Carl Safina, director of the Living Oceans Program of the National Audubon Society , published the book Song for the Blue Ocean. In response to the dramatic changes in fish populations that were being observed, his book urged readers to adopt an interest in the oceans and the growing threat to their ecological stability . Still regarded by many to be an unchangeable expanse and infinite source of goods, Safina alerts readers of the threat of human progress to the ocean, the world's largest ecosystem . Inspiring activism, and some controversy, Safina's book exposes how human activity affects even the ocean's inhabitants. Among the list of species discussed as being in peril is the swordfish.

With efforts such as the restaurant boycott, federal conservation regulation improvements, and social interventions such as the book Song for the Blue Ocean,itis hoped that swordfish populations will make a steady come back within the next decade. Their fate, however, ultimately depends upon consumers, who control demand.

[Eugene C. Beckham ]


RESOURCES

BOOKS

Burton, R., C. Devaney, and T. Long. The Living Sea: An Illustrated Encyclopedia of Marine Life. New York: G. P. Putnam's Sons, 1974.

Hoese, H., and R. Moore. Fishes of the Gulf of Mexico: Texas, Louisiana, and Adjacent Waters. College Station: Texas A&M University Press, 1977.

McClane, A. Field Guide to Saltwater Fishes of North America. New York: Holt, Rinehart, & Winston, 1978.

Nelson, J. Fishes of the World. New York: Wiley, 1976.

Wheeler, A. Fishes of the World: An Illustrated Dictionary. New York: Mac-Millan, 1975.

Swordfish

views updated May 14 2018

Swordfish

The swordfish (Xiphias gladius), also known as the broadbill, or the forktail, is the only species in the bony fish family Xiphiidae. The swordfish is highly prized as a food fish , and as a game fish. Its most distinguishing characteristic is the remarkable elongation of the upper jaw, which resembles a long, flattened, serrated sword and can extend up to one-third of the body length. The sword is used as an offensive weapon, and to spear prey , which may be other fish or large mollusks . Swordfish often attack schools of mackerel , gashing several fish with their sword before devouring them.

Swordfish are dark in color , most often brownish black or black, with a lighter brown below. Adult swordfish are devoid of scales and of teeth. Commercially, swordfish are caught by harpooning, and fish in excess of 1,200 lb (545 kg) have been taken by this method. Swordfish are spotted by their curved dorsal fin exposed above the water surface. Swordfish are also caught by rod-and-reel using heavy tackle, and are baited by trolling squid or mackerel. When hooked, a swordfish will make extreme efforts to free itself by leaping out of the water several times before eventually tiring. The angler may have to patiently play the fish for three or four hours before it is subdued. The record catch for a swordfish by rod-and-reel is 1,182 lb (537 kg).

When injured or hooked, a swordfish may thrust itself out of the water, squirm violently and attack anyone or anything in its path. When approached by a boat, the fish may pretend to be exhausted and then suddenly ram its sword into the side of the boat. The force of the thrust can be sufficient to pierce a 2-in (5 cm) thick, solidwood side of a boat. If the boat hull is wooden, the sword may go in too deep to be removed by the fish, and may be broken off in order to escape.

The sail fish (Istiophorus spp.), spearfish (Tetrapturus spp.), and marlin (Makaira spp.) are relatives of the swordfish, but are placed in the family Istiophoridae.

Swordfish

views updated May 14 2018

Swordfish

The swordfish (Xiphias gladius), also known as the broadbill, or the forktail, is the only species in the bony fish family Xiphiidae. The swordfish is highly prized as a food fish, and as a game fish. Its most distinguishing characteristic is the remarkable elongation of the upper jaw, which resembles a long, flattened, serrated sword and can extend up to one-third of the body length. The sword is used as an offensive weapon, and to stun or kill prey, which may be other fish, squid, or large mollusks. Swordfish often attack schools of mackerel, gashing several fish with their sword before devouring them.

Swordfish are dark in color, most often brownish black or black, with a lighter brown below. Adult swordfish are devoid of scales and of teeth. Commercially, swordfish are caught by harpooning, and fish in excess of 1,200 lb (545 kg) have been taken by this method. Swordfish are spotted by their curved dorsal fin exposed above the water surface. Swordfish are also caught by rod-and-reel using heavy tackle, and are baited by trolling squid or mackerel. When hooked, a swordfish will make extreme efforts to free itself by leaping out of the water several times before eventually tiring. The angler may have to patiently play the fish for three or four hours before it is subdued. The record catch for a swordfish by rod-and-reel is 1,182 lb (537 kg).

When injured or hooked, a swordfish may thrust itself out of the water, squirm violently and attack anyone or anything in its path. When approached by a boat, the fish may pretend to be exhausted and then suddenly ram its sword into the side of the boat. The force of the thrust can be sufficient to pierce a 2-in (5 cm) thick, solid-wood side of a boat. If the boat hull is wooden, the sword may go in too deep to be removed by the fish, and may be broken off in order to escape.

The sailfish (Istiophorus spp.), spearfish (Tetrapturus spp.), and marlin (Makaira spp.) are relatives of the swordfish, but are placed in the family Istiophoridae.

Swordfish

views updated Jun 27 2018

Swordfish ★★ 2001 (R)

CIA operative Gabriel Shear (Travolta) uses associate Ginger (Berry) to coerce a computer hacker (Jackman), who's just been released from prison, to steal nine billion dollars from a DEA slush fund. In return, the hacker gets a fresh start with his wife and daughter. The plot goes on from there, but it's too convoluted and pointless to bother with. As is usually the case with anything directed by Sena or produced by Joel Silver, the emphasis is on flash, high-energy action set pieces, and collateral damage, all of which is well done, if eventually repetitive, here. Travolta is an expert at playing the smirking supervillain, but it does wear. Jackman and Cheadle give better performances than the flick deserves, and Berry has fun with her obligatory femme fatale role. 99m/C VHS, DVD, Blu-ray Disc, UMD, HD DVD . US John Travolta, Hugh Jackman, Halle Berry, Don Cheadle, Vinnie Jones, Sam Shepard, Zach Grenier, Camryn Grimes, Rudolf Martin, Drea De Matteo; D: Dominic Sena; W: Skip Woods; C: Paul Cameron; M: Christopher Young.

swordfish

views updated May 23 2018

sword·fish / ˈsôrdˌfish/ • n. (pl. same or -fishes) a large edible marine fish (Xiphias gladius, family Xiphiidae) with a streamlined body and a long flattened swordlike snout, related to the billfishes and popular as a game fish.

swordfish

views updated May 23 2018

swordfish (broadbill) Marine fish found worldwide in temperate and tropical seas. A popular food fish, it is silvery-black, dark purple, or blue. Its long, flattened upper jaw, in the shape of a sword, is one-third of its length and used to strike at prey. Length: to 4.5m (15ft); weight: 530kg (1180lb). Family Xiphiidae; species Xiphias gladius.

swordfish

views updated Jun 08 2018

swordfish (Xiphias gladius) See XIPHIIDAE.

swordfish

views updated May 29 2018

swordfish Oily fish, Xiphias gladius.

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