Threadfin
Threadfin | |
---|---|
Atlantic threadfin, Polydactylus octonemus | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Perciformes |
Family: | Polynemidae Rafinesque, 1815[1] |
Genera | |
See text |
Threadfins are silvery grey perciform fish of the family Polynemidae. Found in tropical to subtropical waters throughout the world, the threadfin family contains eight genera and about 40 species.[2] An unrelated species sometimes known by the name threadfin, Alectis indicus, is properly the Indian threadfish (family Carangidae).
Ranging in length from 11 cm (4.5 in) in the dwarf threadfin (Parapolynemus verekeri) to 2 m (6.6 ft) in fourfinger threadfin (Eleutheronema tetradactylum) and giant African threadfin (Polydactylus quadrifilis), threadfins are both important to commercial fisheries as a food fish, and popular among anglers. Their habit of forming large schools makes the threadfins a reliable and economic catch.
Description[]
Their bodies are elongated and fusiform, with spinous and soft dorsal fins widely separated. Their tail fins are large and deeply forked; indicating speed and agility. The mouth is large and inferior; a blunt snout projects far ahead. The jaws and palate possess bands of villiform (fibrous) teeth. Their most distinguishing feature is their pectoral fins: they are composed of two distinct sections, the lower of which consists of three to seven long, thread-like independent rays. Polynemus species may have up to 15 of these modified rays.
In some species, such as the royal threadfin (Pentanemus quinquarius), the thread-like rays may extend well past the tail fin. This feature explains both the common name threadfin and the family name Polynemidae, from the Greek poly meaning "many" and nema meaning "filament". Similar species, such as the mullets (family Mugilidae) and milkfish (family Chanidae) can be easily distinguished from threadfins by their lack of filamentous pectoral rays.
Distribution and habitat[]
Threadfins frequent open, shallow water in areas with muddy, sandy, or silty bottoms; they are rarely seen at reefs. Their pectoral rays are thought to serve as tactile structures, helping to find prey within the sediments. Noted for being euryhaline, threadfins are able to tolerate a wide range of salinity levels. This attribute allows threadfins to enter estuaries and even rivers. They feed primarily on crustaceans and smaller fish.
Reproduction[]
Presumed to be pelagic spawners, threadfins probably release many tiny, buoyant eggs into the water column, which then become part of the plankton. The eggs float freely with the currents until hatching.
Cuisine[]
Threadfin has been used as an ingredient in creating crab stick.
Mariculture[]
In Hawaii, sixfinger threadfins are the subject of commercial open-ocean cage mariculture.[5][6]
Genera and species[]
The species in eight genera are:
- Genus Eleutheronema
- (Jordan & Evermann, 1902) (East Asian fourfinger threadfin)
- Eleutheronema tetradactylum (Shaw, 1804) (Fourfinger threadfin)
- (Bleeker, 1849) (Threefinger threadfin)
- Genus Filimanus
- (Cuvier, 1829) (Sevenfinger threadfin)
- (Cuvier 1829) (Javanese threadfin)
- Feltes 1991 (Splendid threadfin)
- (Jordan & , 1910) (Eightfinger threadfin)
- Feltes 1991 (Indian sevenfinger threadfin)
- (Valenciennes, 1831) (Yellowthread threadfin)
- Genus Galeoides
- Galeoides decadactylus (Bloch, 1795) (Lesser African threadfin)
- Genus Leptomelanosoma
- Leptomelanosoma indicum (Shaw, 1804) (Indian threadfin)
- Genus Parapolynemus
- Parapolynemus verekeri (Saville-Kent, 1889) (Dwarf paradise fish)
- Genus Pentanemus
- Pentanemus quinquarius (Linnaeus, 1758) (Royal threadfin)
- Genus Polydactylus
- (Lay & Bennett, 1839) (Blue bobo)
- , & , 2001 (Slender fivefinger threadfin)
- Motomura, Okamoto & Iwatsuki, 2001 (Long-limb threadfin)
- , Motomura & , 2010 (Sarawak giant threadfin)
- Polydactylus macrochir (Günther, 1867) (King threadfin)
- (Bleeker, 1858) (River threadfin)
- Motomura & Iwatsuki, 2001 (African blackspot threadfin)
- (Bleeker, 1851) (Smallmouth threadfin)
- (Hora, 1926) (Arabian blackspot threadfin)
- (Günther, 1860) (Australian threadfin)
- Munro, 1964 (Blackfin threadfin)
- Polydactylus octonemus (Girard, 1858) (Atlantic threadfin)
- (Günther, 1860) (Littlescale threadfin)
- Seale & Bean, 1907 (Yellow bobo)
- Motomura & Iwatsuki, 2001 (Persian blackspot threadfin)
- Polydactylus plebeius (Broussonet, 1782) (Striped threadfin)
- Polydactylus quadrifilis (Cuvier, 1829) (Giant African threadfin)
- Polydactylus sexfilis (Valenciennes, 1831) (Sixfinger threadfin)
- Polydactylus sextarius (Bloch & Schneider, 1801) (Blackspot threadfin)
- Motomura, Iwatsuki & , 2001 (Largemouth striped threadfin)
- (Linnaeus, 1758) (Barbu)
- Genus Polynemus
- Polynemus aquilonaris Motomura, 2003 (Northern paradise fish)
- Motomura & Tsukawaki, 2006
- Bleeker, 1854 ()
- Myers, 1936 ()
- Motomura & , 2003 ()
- Valenciennes, 1831 ()
- Polynemus multifilis Temminck & Schlegel, 1843 (Elegant paradise fish)
- Polynemus paradiseus Linnaeus, 1758 (Paradise threadfin)
Timeline of genera[]
References[]
- ^ Richard van der Laan; William N. Eschmeyer & Ronald Fricke (2014). "Family-group names of Recent fishes". Zootaxa. 3882 (2): 001–230. doi:10.11646/zootaxa.3882.1.1. PMID 25543675.
- ^ "Inserts for pages 437-441" (PDF). John Wiley & Sons Limited. Retrieved 13 April 2020.
- ^ Froese, Rainer and Pauly, Daniel, eds. (2019). "Polydactylus sexfilis" in FishBase. August 2019 version.
- ^ Suryanata, Krisnawati; Umemoto, Karen N. (2005). "Tension at the nexus of the global and local: culture, property, and marine aquaculture in Hawai'i". Environment and Planning A. 35 (2): 199, 206. CiteSeerX 10.1.1.456.680. doi:10.1068/a35116. S2CID 143928957.
- ^ Lin, DT; Bailey-Brock, JH (2008). "Partial recovery of infaunal communities during a fallow period at an open-ocean aquaculture". Marine Ecology Progress Series. 371: 65–72. Bibcode:2008MEPS..371...65L. doi:10.3354/meps07675.
- ^ Lee, HW; Bailey-Brock, JH; McGurr, MM (2006). "Temporal changes in the polychaete infaunal community surrounding a Hawaiian mariculture operation". Marine Ecology Progress Series. 307: 175–185. Bibcode:2006MEPS..307..175L. doi:10.3354/meps307175.
This article includes a list of general references, but it remains largely unverified because it lacks sufficient corresponding inline citations. (November 2008) |
- Froese, Rainer, and Daniel Pauly, eds. (2006). "Polynemidae" in FishBase. January 2006 version.
- Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology. 364: 560. Archived from the original on 2009-02-20. Retrieved 2011-05-19.
External links[]
- Polynemidae
- Fish of Hawaii
- Taxa named by Constantine Samuel Rafinesque