Swordfish
Swordfish Early | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Istiophoriformes |
Family: | Xiphiidae Swainson, 1839 |
Genus: | Xiphias Linnaeus, 1758 |
Species: | X. gladius
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Binomial name | |
Xiphias gladius | |
Global distribution of swordfish in blue | |
Synonyms[3] | |
The swordfish (Xiphias gladius), also known as the broadbill
They are the sole member of their family, Xiphiidae.[6]
Taxonomy and etymology
The swordfish is named after its long pointed, flat bill, which resembles a
Several extinct genera are known, such as a large sized Xiphiorhynchus and Aglyptorhynchus.[8] Unlike modern taxa these have equally long lower jaws.[citation needed]
Description
They commonly reach 3 m (10 ft) in length, and the maximum reported is 4.55 m (14 ft 11 in) in length and 682 kg (1,500 lb) in weight.
They reach maturity at 4–5 years of age and the maximum age is believed to be at least 9 years.[5] 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.[10]
Temperature regulation
Swordfish are ectothermic animals; however, along with some species of sharks, they have special organs next to their eyes to heat their eyes and brains.[11][page needed] 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.[12][13]
The swordfish is one of 22 species of fish – including the marlin, tuna, and some sharks – known to have a heat-conservation mechanism.[12][13]
Behavior and ecology
Movements and feeding
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 [5]. 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 100 km/h (60 mph) is unreliable.
Swordfish are not
Swordfish prefer water temperatures between 18 and 22 °C (64 and 72 °F),
Threats and parasites
Almost 50 species of
Fully adult swordfish have few natural predators. Among marine mammals,
Human fishery is a major predator of swordfishes. The annual reported catch in 2019 of the North Atlantic swordfish amounted to a total of 1.3 million kilograms (2.9 million pounds).[21]
Breeding
In the North Pacific, batch spawning mainly occurs in water warmer than 24 °C (75 °F) during the spring and summer, and year-round in the equatorial Pacific.[2] In the North Atlantic, spawning is known from the Sargasso Sea,[22] and in water warmer than 23 °C (73 °F) and less than 75 m (246 ft; 41 fathoms) deep.[2] Spawning occurs from November to February in the South Atlantic off southern Brazil.[2] Spawning is year-round in the Caribbean Sea and other warm regions of the west Atlantic.[5]
Large females can carry more eggs than small females, and between 1 million and 29 million eggs have been recorded.[2] The pelagic eggs measure 1.6–1.8 mm (1⁄16–5⁄64 in) in diameter and 2+1⁄2 days after fertilization, the embryonic development occurs.[22][5] The surface-living and unique-looking larvae are 4 mm (5⁄32 in) long at hatching.[3][5] The bill is evident when the larvae reach 1 cm (3⁄8 in) in length.[3]
Fisheries
Swordfish were harvested by a variety of methods at small scale (notably
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.[27]
Recreational fishing
This section needs additional citations for verification. (February 2010) |
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 2.5 kg (5 lb) or more of weight to get the baits deep enough during the day, up to 460 m (1,500 ft) is common.[28] Night fishing baits are usually fished much shallower, often less than 90 m (300 ft; 50 fathoms). 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 food
Swordfish are classified as
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.[citation needed]
Swordfish is a particularly popular fish for cooking. Since swordfish are large, meat is usually sold as steaks, which are often
Kashrut
A dispute exists as to whether swordfish should be considered a
Conservation status
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.[36]
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.
In the North Atlantic, the swordfish stock is fully rebuilt, with biomass estimates currently 5% above the target level.[37] 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.[38]
In 2010,
Extinct
In culture
- The swordfish (Xiphias) has been used by astronomers as another name for the constellation of Dorado.[citation needed]
References
- ^ Fierstine, Harry L. (1990). "A paleontological review of three billfish families (Istiophoridae, Xiphiidae, and Xiphiorhynchidae)" (PDF). Biological Sciences: 11.
- ^ . Retrieved 14 October 2022.
- ^ a b c d e f Froese, Rainer; Pauly, Daniel (eds.) (2018). "Xiphias gladius" in FishBase. February 2018 version.
- ISBN 9781493048809.
- ^ a b c d e f g h i j k l m n o p Gardieff, S. "Swordfish". Florida Museum of Natural History. Archived from the original on 9 August 2015. Retrieved 26 December 2011.
- ^ Froese, Rainer, and Daniel Pauly, eds. (2011). "Xiphiidae" in FishBase. December 2011 version.
- ISBN 978-0-226-65539-0
- S2CID 20606448.
- ISBN 978-3-540-30147-9.
- ^ Marsh, Jesse; Stiles, Margot (2007). "Seafood Watch, Seafood Report, Monterey Bay Aquarium" (PDF). Archived from the original (PDF) on 2 February 2017.
- ISBN 9781133784579.
- ^ S2CID 14070646.
- ^ .
- ^ "Haulin' Bass". ReefQuest Centre for Shark Research. Retrieved 26 December 2011.
The 60 mph figure listed for the swordfish is based on a corrupted version of calculations made by Sir James Gray to estimate the impact speed necessary for a hypothetical 600 lb [270 kg] swordfish to embed its sword 3 feet [90 cm] in the timbers of ships, as has been known to occur; the figure seems to have entered the literature without question.
- PMID 27543056.
- .
- S2CID 235404099.
- PMID 25057787.
- ^ The Shark Trust. "Shortfin mako". Archived from the original on 14 July 2011. Retrieved 26 December 2011.
- ^ a b Sokol, Joshua (27 October 2020). "Sharks Wash up on Beaches, Stabbed by Swordfish". The New York Times. Retrieved 5 January 2023.
- ^ "North Atlantic Swordfish | FishWatch". www.fishwatch.gov. Retrieved 14 May 2021.
- ^ a b Froese, Rainer; Pauly, Daniel (eds.) (2011). "Xiphias gladius" in FishBase. December 2011 version.
- ^ "Aquatic species: Xiphias gladius (Linnaeus, 1758)". Food and Agriculture Organization. Retrieved 5 January 2023.
- ^ "La Pesca del Pescespada". Archived from the original on 26 April 2012. Retrieved 30 December 2011.
- ^ "La pesca del pesce spada". www.biologiamarina.eu.
- ^ "La tecnica per la pesca del pescespada e la "Feluca" - Ganzirri, il Peloro e lo Stretto di Messina". www.ganzirri.it.
- ^ Preuss, Andreas; Marco, Tony (1 June 2015). "Swordfish kills fisherman in Hawaii". CNN.com.
- ^ "Daytime Swordfish Tactics That Work Like a Charm". FishingBooker.com. 13 October 2018.
- ^ "What's an oily fish?". Food Standards Agency. 24 June 2004. Archived from the original on 10 December 2010. Retrieved 8 July 2009.
- ^ FDA (1990–2010). "Mercury Levels in Commercial Fish and Shellfish". Food and Drug Administration. Retrieved 14 September 2011.
- ^ EPA. "What you need to know about mercury in fish and shellfish". Retrieved 14 September 2011.
- FDA. Retrieved 27 September 2019.
- ^ "Swordfish: The Fish of Legends". The Biblical Museum of Natural History. Retrieved 8 April 2023.
- ^ "Is Swordfish Kosher?". Retrieved 8 April 2023.
- ^ "The Turning of the Tide: The Kashrut Tale of the Swordfish" (PDF). Bar-Ilan University. Retrieved 8 April 2023.
- ^ "Swordfish". Fenton Communications. Archived from the original on 31 December 2007.
- ^ "Species directory: North Atlantic Swordfish". NOAA.gov. 28 December 2022. Retrieved 5 January 2023.
- ^ "Seafood Watch – Seafood Report – Swordfish" (PDF). Monterey Bay Aquarium. Archived from the original (PDF) on 14 July 2007. Retrieved 16 July 2008.
- ^ "Greenpeace International Seafood Red List" (PDF). October 2010. Archived from the original (PDF) on 10 November 2011. Retrieved 14 September 2012.
Further reading
- Richard Ellis (2013). Swordfish: A Biography of the Ocean Gladiator. University of Chicago Press. ISBN 978-0226922904.