Largehead hairtail

Largehead hairtails are silvery steel blue in color, turning silvery gray after death. and in length. Most are only long, although they regularly reach in Australia. == Range and habitat ==

Largehead hairtails are found worldwide in tropical and temperate oceans. In the West Atlantic it ranges from Virginia (occasionally Cape Cod) to northern Argentina, including the Caribbean Sea and Gulf of Mexico. In the East Pacific they range from southern California to Peru. Some populations are migratory. Based on fishing catches in the Jeju Strait of South Korea, the species resides mainly in water warmer than , while catches are poor in colder water. Off southern Brazil it mainly occurs in waters warmer than . It is absent from waters below . The largehead hairtail prefers relatively shallow coastal regions over muddy bottoms, but it sometimes enters estuaries and has been recorded at depths of . In European waters, most records are from , Off southern Brazil hairtails are most abundant between , they have been recorded between in the East Pacific, and in southern Japan's Bungo Channel they are primarily known from but most common between . They are mainly benthopelagic, but may appear at the surface during the night. == Taxonomy ==

Although often considered a single highly widespread species, Morphometric and meristic differences have also been shown in the population of the East Pacific (California to Peru), leading some to recognize it as T. nitens. Neither T. japonicus nor T. nitens are recognized as separate species by FishBase where considered synonyms of T. lepturus, The IUCN recognizes the East Atlantic population as a distinct, currently undescribed species. It is likely that Trichiurus sp. 2 equals T. nanhaiensis. The names T. coxii and T. haumela have been used for the populations off Australia and in the Indo-Pacific, respectively, but firm evidence supporting their validity as species is lacking. ==Behavior and life cycle==

Juveniles participate in the diel vertical migration, rising to feed on krill and small fish during the night and returning to the sea bed in the day. This movement pattern is reversed by large adults, which mainly feed on fish. Largehead hairtails are often found in large, dense schools. Spawning depends on temperature as the larvae prefer water warmer than and are entirely absent at less than . Consequently, spawning is year-round in tropical regions, but generally in the spring and summer in colder regions. Through a spawning season each female lays many thousand pelagic eggs that hatch after three to six days. In the Sea of Japan most individuals reach maturity when two years old, but some already after one year. The oldest recorded age is 15 years. ==Fisheries and usage==

Largehead hairtail is a major commercial species. With reported landings of more than 1.3 million tonnes in 2009, it was the sixth most important captured fish species. The species is caught throughout much of its range, typically by bottom trawls or beach seines, but also using a wide range of other methods. It is popular for frying or grilling. In Japan, where it is known as tachiuo (" (tachi)": sword, " (uo)": fish), they are fished for food and eaten grilled or raw, as sashimi. They are also called "sword-fish" in Portugal and Brazil (peixe-espada), where they are eaten grilled or fried. Its flesh is firm yet tender when cooked, with a moderate level of "fishiness" to the smell and a low level of oiliness. The largehead hairtail is also notable for being fairly easy to debone. Dried Trichiurus lepturus at Cox's Bazar 2.jpg|Drying at Cox's Bazar, Bangladesh Galchi-gui 1.jpg|Korean galchi-gui (grilled largehead hairtail) Galchi-hoe.jpg|Korean galchi-hoe (raw largehead hairtail) Galchi-jorim.jpg|Korean galchi-jorim (simmered largehead hairtail) Keripik Ikan Beledang - IMG 20220211 133740 620.jpg|Kripik Beledang (battered and deep-fried hairtail) from Bengkulu, Indonesia File:Trichiurus lepturus Sushi.JPG|Japanese oshizushi with hairtail ==References==