Swordfish
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The swordfish (Xiphias gladius), also known as the broadbill<ref>Template:Cite book</ref> in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are the sole member of the family Xiphiidae.<ref>{{#invoke:Cite taxon|main|fishbase|genus=|species=|subspecies=}}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> They are a popular sport fish of the billfish category. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood. These fish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans, and can typically be found from near the surface to a depth of Template:Convert, and exceptionally up to depths of 2,234 m.<ref name=IUCN/> They commonly reach Template:Convert in length, and the maximum reported is Template:Convert in length and Template:Convert in weight.<ref name=FishBase/><ref name=Florida>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Taxonomy and etymologyEdit
The swordfish is named after its long pointed, flat bill, which resembles a sword. The species name, Xiphias gladius, derives from Greek Template:Wikt-lang (xiphias, "swordfish"), itself from Template:Wikt-lang (xiphos, "sword") and from Latin Template:Wikt-lang ("sword").<ref name=Florida/> This makes it superficially similar to other billfish such as marlin, but upon examination, their physiology is quite different and they are members of different families.<ref>Pepperell, J. 2010. Fishes of the Open Ocean: A Natural History and Illustrated Guide. Template:ISBN</ref>
Several extinct genera are known, such as a large sized Xiphiorhynchus and Aglyptorhynchus.<ref>Template:Cite journal</ref> Unlike modern taxa these have equally long lower jaws.Template:Citation needed
DescriptionEdit
They commonly reach Template:Convert in length, and the maximum reported is Template:Convert in length and Template:Convert in weight.<ref name=FishBase/><ref name=Florida/><ref>Template:Cite book</ref> The International Game Fish Association's all-tackle angling record for a swordfish was a Template:Convert specimen taken off Chile in 1953.<ref name=IUCN/> Females are larger than males, and Pacific swordfish reach a greater size than northwest Atlantic and Mediterranean swordfish.<ref name=Florida/>
They reach maturity at 4–5 years of age and the maximum age is believed to be at least 9 years.<ref name=Florida/> The oldest swordfish found in a recent study were a 16-year-old female and 12-year-old male. Swordfish ages are derived, with difficulty, from annual rings on fin rays rather than otoliths, since their otoliths are small in size.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Temperature regulationEdit
Swordfish are ectothermic animals. Along with some species of sharks, they have special organs next to their eyes called heater cells which function to heat their eyes and brains.<ref>Template:Cite book</ref> Their eyes are heated to temperatures measured between 10 and 15 °C (18 and 27 °F) above the surrounding water temperature; this heating greatly improves their vision and, consequently, their predatory efficacy.<ref name=warmeye1>Template:Cite journal</ref><ref name=warmeye2>Template:Cite journal</ref>
The swordfish is one of 22 species of fish – including the marlin, tuna, and some sharks – known to have a heat-conservation mechanism.<ref name=warmeye1/><ref name=warmeye2/>
Behavior and ecologyEdit
Movements and feedingEdit
The popular image of the swordfish skewering its prey with its nose is based on little evidence. In a typical environment, swordfish most likely use their noses to slash at prey and inflict weakening injuries.<ref name=Florida/> The hypothesis that they may use their noses as spears in a defensive capacity against sharks and other predators is still under review.
Mainly, the swordfish relies on its great speed and agility in the water to catch its prey. It is no doubt among the fastest fish, but the basis for the frequently-quoted speed of Template:Convert is unreliable.<ref name=speed>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Research on related marlin (Istiophorus platypterus) suggest a maximum value of Template:Convert is more likely.<ref>Template:Cite journal</ref>
Swordfish are not schooling fish. They swim alone or in very loose aggregations, separated by as much as Template:Convert from a neighboring swordfish. They are frequently found basking at the surface, airing their first dorsal fin. Boaters report this to be a beautiful sight, as is the powerful jumping for which the species is known. This jumping, also called breaching, may be an effort to dislodge pests, such as remoras or lampreys.Template:Citation needed
Swordfish prefer water temperatures between Template:Convert,<ref name=IUCN/> but have the widest tolerance among billfish, and can be found from Template:Convert.<ref name=Florida/> This highly migratory species typically moves towards colder regions to feed during the summer.<ref name=Florida/> Swordfish feed daily, most often at night, when they rise to surface and near-surface waters in search of smaller fish. During the day, they commonly occur to depths of Template:Convert and have exceptionally been recorded as deep as Template:Convert.<ref name=IUCN/> Adults feed on a wide range of pelagic fish, such as mackerel, barracudinas, silver hake, rockfish, herring, and lanternfishes, but they also take demersal fish, squid, and crustaceans.<ref name=FishBase/><ref name=Florida/> In the northwestern Atlantic, a survey based on the stomach content of 168 individuals found 82% had eaten squid and 53% had eaten fish, including gadids, scombrids, butterfish, bluefish, and sand lance.<ref>Template:Cite journal</ref> Large prey are typically slashed with the sword, while small are swallowed whole.<ref name=Florida/>
Threats and parasitesEdit
Almost 50 species of parasites have been documented in swordfish. In addition to remoras, lampreys, and cookiecutter sharks, this includes a wide range of invertebrates, such as tapeworms, roundworms, Myxozoans and copepods.<ref name=Florida/><ref>Template:Cite journal</ref> A comparison of the parasites of swordfish in the Atlantic and in the Mediterranean indicated that some parasites, particularly Anisakis spp. larvae identified by genetic markers, could be used as biological tags and support the existence of a Mediterranean swordfish stock.<ref>Template:Cite journal</ref>
Fully adult swordfish have few natural predators. Among marine mammals, killer whales sometimes prey on adult swordfish.<ref name=Florida/> It is believed that sperm whales may also prey on swordfish on rare occasions.<ref>Template:Cite journal</ref> The shortfin mako, an exceptionally fast species of shark, sometimes take on swordfish; dead or dying shortfin makos have been found with broken-off swords in their heads, revealing the danger of this type of prey.<ref name=mako>The Shark Trust. {{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Juvenile swordfish are far more vulnerable to predation, and are eaten by a wide range of predatory fish.<ref name=Florida/><ref name="nty20201027">Template:Cite news</ref> Intensive fishery may be driving swordfishes and sharks into harder competition for reduced amounts of prey and therefore pitting them to fight more.<ref name="nty20201027" />
Human fishery is a major predator of swordfishes. The annual reported catch in 2019 of the North Atlantic swordfish amounted to a total of Template:Convert.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
BreedingEdit
In the North Pacific, batch spawning mainly occurs in water warmer than Template:Convert during the spring and summer, and year-round in the equatorial Pacific.<ref name=IUCN/> In the North Atlantic, spawning is known from the Sargasso Sea,<ref name=fishbase>{{#invoke:Cite taxon|main|fishbase|genus=|species=|subspecies=}}</ref> and in water warmer than Template:Convert and less than Template:Convert deep.<ref name=IUCN/> Spawning occurs from November to February in the South Atlantic off southern Brazil.<ref name=IUCN/> Spawning is year-round in the Caribbean Sea and other warm regions of the west Atlantic.<ref name=Florida/>
Large females can carry more eggs than small females, and between 1 million and 29 million eggs have been recorded.<ref name=IUCN/> The pelagic eggs measure Template:Convert in diameter and Template:Frac days after fertilization, the embryonic development occurs.<ref name=fishbase/><ref name=Florida/> The surface-living and unique-looking larvae are Template:Convert long at hatching.<ref name=FishBase/><ref name=Florida/> The bill is evident when the larvae reach Template:Convert in length.<ref name=FishBase/>
FisheriesEdit
Swordfish were harvested by a variety of methods at small scale (notably harpoon fishing) until the global expansion of long-line fishing. They have been fished widely since ancient times in places such as the Strait of Messina, where they are still fished with traditional wooden boats called feluccas and are part of the cuisine in that area.<ref name="auto">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="auto3">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="auto2">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Swordfish are vigorous, powerful fighters. Although no unprovoked attacks on humans have been reported, swordfish can be very dangerous when harpooned. They have run their swords through the planking of small boats when hurt. In 2015, a Hawaiian fisherman was killed by a swordfish after attempting to spear the animal.<ref name="auto1">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Recreational fishingEdit
Template:More citations needed section Recreational fishing has developed a subspecialty called swordfishing. Because of a ban on long-lining along many parts of seashore, swordfish populations are showing signs of recovery from the overfishing caused by long-lining along the coast.
Various ways are used to fish for swordfish, but the most common method is deep-drop fishing, since swordfish spend most daylight hours very deep, in the deep scattering layer. The boat is allowed to drift to present a more natural bait. Swordfishing requires strong fishing rods and reels, as swordfish can become quite large, and it is not uncommon to use Template:Convert or more of weight to get the baits deep enough during the day, up to Template:Convert is common.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Night fishing baits are usually fished much shallower, often less than Template:Convert. Standard baits are whole mackerel, herring, mullet, bonito, or squid; one can also use live bait. Imitation squids and other imitation fish lures can also be used, and specialized lures made specifically for swordfishing often have battery-powered or glow lights. Even baits are typically presented using glow sticks or specialized deepwater-proof battery operated lights.
As foodEdit
- Unfinished cutting of swordfish, Cefalù, Sicily.jpg
Swordfish in seafood shop
- Marinated grill swordfish.jpeg
Marinated swordfish
- Fried Swordfish collar.jpg
Fried swordfish collars
- Swordfish in Limnionas, Kos, Greece (5653643083).jpg
Swordfish dish in Kos
Swordfish are classified as oily fish.<ref>Template:Cite news</ref> Many sources, including the United States Food and Drug Administration, warn about potential toxicity from high levels of methylmercury in swordfish.<ref name="Mercury Levels in Commercial Fish and Shellfish">{{#invoke:citation/CS1|citation |CitationClass=web }}Template:Dead linkTemplate:Cbignore </ref><ref name="What you need to know about mercury in fish and shellfish">{{#invoke:citation/CS1|citation |CitationClass=web }} </ref> The FDA recommends that young children, pregnant women, and women planning to become pregnant not eat swordfish.<ref>Template:Cite news</ref>
The flesh of some swordfish can acquire an orange tint, reportedly from their diet of shrimp or other prey. Such fish are sold as "pumpkin swordfish", and command a premium over their whitish counterparts.Template:Citation needed
Swordfish is a particularly popular fish for cooking. Since swordfish are large, meat is usually sold as steaks, which are often grilled. Swordfish meat is relatively firm, and can be cooked in ways more fragile types of fish cannot (such as over a grill on skewers). The color of the flesh varies by diet, with fish caught on the East Coast of North America often being rosier.
KashrutEdit
A dispute exists as to whether swordfish should be considered a kosher fish according to the laws of kashrut. Standard Orthodox opinion is that swordfish is not kosher, while Conservative Judaism does consider swordfish kosher. All kosher fish must have both fins and scales. The Talmud and the Tosefta are believed by some to present swordfish ("achsaftias") as an example of a kosher fish without scales because swordfish are born with scales they later shed once attaining a length of about 1 meter. The 17th-century Turkish Sephardi halakhic authority Rabbi Chaim ben Yisrael Benvenisti wrote that "It is a widespread custom among all Jews to eat the fish with the sword, known in vernacular as fishei espada, even though it does not have any scales. Because it is said that when it comes out of the water, due to its anger, it shakes and throws off its scales." A 1933 list of kosher fish published by the Agudas HaRabbonim includes swordfish. The following year, Rabbi Yosef Kanowitz published the same list of kosher fish with swordfish still included. Swordfish was widely considered kosher by halakhic authorities until the 1950s. Orthodox opinion began to shift in 1951, when Rabbi Moshe Tendler examined swordfish and decided it was not kosher due to the lack of scales. Tendler's opinion provoked strong debate among halakhic authorities during the 1960s.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Among Mediterranean Jews there was a longstanding minhag of considering swordfish kosher. Swordfish was and possibly still is consumed by Jews in Italy, Turkey, Gibraltar, Morocco, Tunisia, and England. Due to Tendler's opinion, swordfish are generally not considered kosher by "Orthodox" Jews in the United States and Israel.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Conservation statusEdit
In 1998, the U.S. Natural Resources Defense Council and SeaWeb hired Fenton Communications to conduct an advertising campaign to promote their assertion that the swordfish population was in danger due to its popularity as a restaurant entree.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The resulting "Give Swordfish a Break" promotion was wildly successful, with 750 prominent U.S. chefs agreeing to remove North Atlantic swordfish from their menus, and also persuaded many supermarkets and consumers across the country.
The advertising campaign was repeated by the national media in hundreds of print and broadcast stories, as well as extensive regional coverage. It earned the Silver Anvil award from the Public Relations Society of America, as well as Time magazine's award for the top five environmental stories of 1998.
Subsequently, the U.S. National Marine Fisheries Service proposed a swordfish protection plan that incorporated the campaign's policy suggestions. Then-US President Bill Clinton called for a ban on the sale and import of swordfish and in a landmark decision by the federal government, Template:Convert of the Atlantic Ocean were placed off-limits to fishing as recommended by the sponsors.
In the North Atlantic, the swordfish stock is fully rebuilt, with biomass estimates currently 5% above the target level.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> No robust stock assessments for swordfish in the northwestern Pacific or South Atlantic have been made, and data concerning stock status in these regions are lacking. These stocks are considered unknown and a moderate conservation concern. The southwestern Pacific stock is a moderate concern due to model uncertainty, increasing catches, and declining catch per unit effort. Overfishing is likely occurring in the Indian Ocean, and fishing mortality exceeds the maximum recommended level in the Mediterranean, thus these stocks are considered of high conservation concern.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
In 2010, Greenpeace International added the swordfish to its seafood red list.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
ExtinctEdit
Relationship with humansEdit
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Notable incidentsEdit
In 2007, a fisherman died after being attacked by a swordfish which pierced his eye and its bill penetrated into the man's skull.<ref>Template:Cite journal</ref>
In 2024, Giulia Manfrini, an Italian surfer died in a rare incident after being struck by a swordfish while surfing off the coast of West Sumatra, Indonesia.<ref>Template:Cite news</ref>
In cultureEdit
The swordfish (Xiphias) has been used by astronomers as another name for the constellation of Dorado.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The word swordfish is used as a password in the 1932 Marx Brothers film Horse Feathers. It has since appeared as a password in many films, television series, books, and videogames.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
ReferencesEdit
Further readingEdit
External linksEdit
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