Editing Lancetfish

{{Short description|Family of ray-finned fishes}}
{{For|the United States Navy submarine|USS Lancetfish (SS-296)}}
{{Automatic taxobox
| name = Lancetfishes
| fossil_range = {{Fossil range|Middle Miocene|Recent|Middle Miocene-Recent<ref>{{cite journal|last=Sepkoski |first=J. |title=A compendium of fossil marine animal genera |journal=Bulletins of American Paleontology |volume=364 |year=2002 |url=http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |access-date=2008-01-08 |url-status=dead |archiveurl=https://web.archive.org/web/20110723131237/http://strata.ummp.lsa.umich.edu/jack/showgenera.php?taxon=611&rank=class |archivedate=2011-07-23 }}</ref>}}
| image = Alepisaurus ferox on deck.jpg
| image_caption = Longnose lancetfish, ''Alepisaurus ferox''
| parent_authority = [[William Swainson|Swainson]], 1839
| taxon = Alepisaurus
| authority = [[Richard Thomas Lowe|R. T. Lowe]], 1833
| subdivision_ranks = Species
| subdivision = 
}}

'''Lancetfishes''' are large [[ocean]]ic [[predator]]y [[ray-finned fish]]es in the genus '''''Alepisaurus''''' ("scaleless lizard") in the [[monotypic taxon|monogeneric family]] '''Alepisauridae'''.<ref>{{FishBase family | family = Alepisauridae | month = February | year = 2006}}</ref>

Lancetfishes grow up to {{convert|2|m|ft|abbr=on}} in length. Very little is known about their [[biology]], though they are  widely distributed in all oceans, except the [[polar region|polar]] [[sea]]s.<ref>{{cite journal |author1=Kubota, T. |author2=Uyeno, T. | year = 1978 | title = On some meristic characters of lancetfish, ''Alepisaurus'', collected from Suruga Bay, Japan | journal = Journal of Faculty of Marine Science and Technology, Tokai University | volume = 11 | pages = 63–69 | url = http://eurekamag.com/research/006/024/on-meristic-characters-lancetfish-alepisaurus-collected-suruga-bay-japan.php }}</ref> Specimens have been recorded as far north as [[Greenland]].<ref>{{cite book | author = Jensen, A. S. | year = 1948 | title = Contributions to the Ichthyofauna of Greenland | series = Skrifter Univ. Zool. Mus. Københaven | volume = 9 | pages = 1–182 | oclc = 83357750 }}</ref> They are often caught as bycatch by vessels long-lining for [[tuna]].

The [[genus|generic]] name is from [[Greek language|Greek]] ''a-'' meaning "without", ''{{Transliteration|el|lepis}}'' meaning "scale", and ''sauros'' meaning "lizard".

==Species==
The two currently recognized extant species in this genus are:<ref>{{FishBase genus | genus = Alepisaurus| month = February | year = 2012}}</ref>
* ''[[Alepisaurus brevirostris]]'' <small>[[Robert Henry Gibbs|Gibbs]], 1960</small> (short-snouted lancetfish)
* ''[[Alepisaurus ferox]]'' <small>[[Richard Thomas Lowe|R. T. Lowe]], 1833</small> (long-snouted lancetfish)

The anatomic difference between the two species is the shape of the snout, which is long and pointed in ''A. ferox'', and slightly shorter in ''A. brevirostris''. The long-snouted lancetfish is found in the tropical and northern sub-tropical waters of the [[Pacific Ocean]]. The short-snouted lancetfish lives in the [[Atlantic Ocean]]'s tropics, subtropics, and southern sub-tropics of the Pacific ocean. A third recognized species, ''[[Alepisaurus paronai|A. paronai]]'' <small>D'Erasmo, 1923</small>,<ref name="uyeno">Uyeno, Teruya. "A Miocene alepisauroid fish of a new family, Polymerichthyidae, from Japan." Bull. Nat. Sci. Mus 10 (1967): 383–394.</ref> is a fossil known from Middle Miocene-aged strata from Italy.

==Description==
[[File:Lancetfish Alepisaurus ferox Okeanos 2017 (cropped).jpg|thumb|A lancetfish in the [[midwater]] facing upwards towards the surface]]
Lancetfish possess a long and very high [[dorsal fin]], soft-rayed from end to end, with an [[adipose fin]] behind it. The dorsal fin has 41 to 44 [[Fish anatomy#Spines and rays|rays]] and occupies the greater length of the back. This fin is rounded in outline, about twice as high as the fish is deep, and can be depressed into a groove along the back. The body is slender, flattened from side to side, deepest at the [[operculum (fish)|gill cover]]s, and tapers back to a slender [[caudal peduncle]].

The mouth is wide, gaping to the back of the eye, and each jaw has two or three large, fang-like teeth, in addition to numerous smaller [[teeth]]. The [[caudal fin]] is very deeply [[fork]]ed; its upper [[Lobe (anatomy)|lobe]] is prolonged as a long filament, although most lancetfishes seem to lose this when captured. The [[anal fin]] originates under the last dorsal ray, and is deeply concave in outline. The [[ventral fin]]s are about halfway between the anal fin and the tip of the snout, while the [[pectoral fin]]s are considerably longer than the body is deep and are situated very low down on the sides. No [[scale (zoology)|scale]]s are present, and the fins are very fragile.

Lancetfishes are among the largest living bathypelagic fish forms. Specimens have been collected in excess of {{convert|2080|mm|ft|abbr=on}} in length, often from dead individuals that drifted ashore. Like their close relatives in the [[Aulopiformes]] suborder Alepisauroidei, lancetfish lack [[swimbladder]]s and are simultaneous [[hermaphrodites]].<ref name=FWNA>{{cite book |editor= Olsen, Y.H. |editor2=Atz, J.W. |author=Rofen R.R. |name-list-style=amp |year=1966|title=Fishes of the Western North Atlantic Number 1. Part 5|publisher=Yale University|location=New Haven|pages= 482–497}}</ref>

==Ecology and life history==
[[File:Lancetfish smithsonian.JPG|thumb|A lancetfish model in the Smithsonian National Museum of Natural History in Washington, DC]]
Lancetfish have large mouths and sharp teeth, indicating a predatory mode of life. Their watery muscle is not suited to fast swimming and long pursuit, so they likely are ambush predators, using their narrow body profile and silvery coloration to conceal their presence. Lancetfish float in the water column, using their large eyes to scan for prey, which once detected, they attack using their forked tails for rapid bursts of speed, their large dorsal sails are likely used to maintain a stable trajectory toward their target, and their large mouths and teeth are used to subdue prey before it can escape. They are voracious predators and their distensible stomachs have often been found to contain a variety of food, mainly fishes, octopods, squid, [[tunicates]], and [[crustacea]].<ref name=FWNA>{{cite book |editor= Olsen, Y.H. |editor2=Atz, J.W. |author=Rofen R.R. |name-list-style=amp |year=1966|title=Fishes of the Western North Atlantic Number 1. Part 5|publisher=Yale University|location=New Haven|pages= 482–497}}</ref>

Extremely little is known of lancetfish reproductive habits. While they are known to be simultaneous hermaphrodites, spawning has never been observed. They likely are [[planktonic]] [[spawners]] from the small size and pelagic transmission of their larva. While seasonal presences and absences of lancetfish capture have been noted in certain ocean basins, it remains unclear whether  spawning is a seasonal occurrence.

No commercial fisheries exist for lancetfishes. Their flesh is watery and gelatinous, although edible and reportedly sweet to taste. They are caught as [[bycatch]] by tuna fisheries and are often considered [[pest (animal)|pests]], taking bait intended for more valuable species. Data from longline fisheries in the central and western Pacific indicates an apparent increase in lancetfish bycatch. This increase is thought by researchers to reflect a faunal regime shift as other commercially target species, like yellowfin and bigeye tuna populations are reduced through fishing.

Lancetfishes have been caught on longlines as shallow as ten fathoms in Oregon and the Gulf of Mexico. Some anecdotal reports have observed shoals of 30–40 individuals at the surface in Icelandic waters during spring. Hook and line capture of lancetfish from surf zones is not unheard of and dietary surveys suggest at least some feeding occurs within inshore waters. However, lancetfish are generally considered solitary, [[mesopelagic]], and [[bathypelagic]] fishes occupying depths between 100 and 2000 m. While they have not been shown to participate in [[diel vertical migration]], they have been found in a huge variety of depths.<ref name=FWNA>{{cite book |editor= Olsen, Y.H. |editor2=Atz, J.W. |author=Rofen R.R. |name-list-style=amp |year=1966|title=Fishes of the Western North Atlantic Number 1. Part 5|publisher=Yale University|location=New Haven|pages= 482–497}}</ref>

The [[tetraphyllidea]]n [[tapeworm]] ''[[Pelichnibothrium speciosum]]'' is a significant [[parasite]] of long-snouted lancetfish. The species seems to be an [[intermediate host|intermediate]] or [[paratenic]] host for the tapeworm.<ref>{{ cite journal |author1=Scholz, T. |author2=Euzet, L. |author3=Moravec, F. | year = 1998 | title = Taxonomic status of ''Pelichnibothrium speciosum'' Monticelli, 1889 (Cestoda: Tetraphyllidea), a mysterious parasite of ''Alepisaurus ferox'' Lowe (Teleostei: Alepisauridae) and ''Prionace glauca'' (L.) (Euselachii: Carcharinidae) | journal = Systematic Parasitology | volume = 41 | issue = 1 | pages = 1–8 | doi = 10.1023/A:1006091102174 |s2cid=33831101 }}</ref>

The large size, wide depth distribution, and opportunistic diet of lancetfish have lent them to the study of other [[pelagic]] [[biodiversity]] because their voraciousness can be used to survey smaller organisms throughout the deep-sea that are difficult to capture by other means.<ref name=alepPlastic>{{cite journal|last1=Choy|first1=C.A.|last2=Portner|first2=E.|last3=Iwane|first3=M.|last4=Drazen|first4=J.C.|year=2013|title=Diets of five important predatory mesopelagic fishes of the central North Pacific|journal=Mar Ecol Prog Ser|volume=492|pages=169–184|doi=10.3354/meps10518|doi-access=free}}</ref> Adult lancetfish are commonly caught as bycatch in longline fisheries and analysis of their gut contents provides a convenient, if somewhat biased, method for surveying regional pelagic biodiversity, so much so that some species of deep-sea fishes were first described from specimens found in the stomachs of lancetfish.
This may be partially due to the unusually slow rate of digestion apparent in lancetfish, where actual digestion seemingly does not begin in earnest until the beginning of the small intestines.<ref name=FWNA>{{cite book |editor= Olsen, Y.H. |editor2=Atz, J.W. |author=Rofen R.R. |name-list-style=amp |year=1966|title=Fishes of the Western North Atlantic Number 1. Part 5|publisher=Yale University|location=New Haven|pages= 482–497}}</ref><ref name=alepIndia2>{{cite journal|last1=Romanov|first1=E.V.|last2=Ménard|first2=F.|last3=Zamorov|first3=V.V.|first4=M.|last4=Potier|year=2008|title=Variability in conspecific predation among longnose lancetfish Alepisaurus ferox in the western Indian Ocean|journal=Fisheries Science|volume=74|issue=1|pages=62–68|doi=10.1111/j.1444-2906.2007.01496.x|s2cid=42124144}}</ref><ref name=alepPlastic>{{cite journal|last1=Choy|first1=C.A.|last2=Portner|first2=E.|last3=Iwane|first3=M.|last4=Drazen|first4=J.C.|year=2013|title=Diets of five important predatory mesopelagic fishes of the central North Pacific|journal=Mar Ecol Prog Ser|volume=492|pages=169–184|doi=10.3354/meps10518|doi-access=free}}</ref><ref name=alep66>{{cite journal|last1=Haedrich|first1=R.L.|last2=Nielsen|first2=J.G.|year=1966|title=Fishes eaten by Alepisaurus (Pisces, Iniomi) in the southeastern Pacific Ocean|journal=Deep-Sea Res.|volume=13|pages=909–919}}</ref>
[[File:Alepisaurus ferox PC14-04 sta16 IMG 6741.jpg|thumb|A small lancetfish, photo by Dr. Jon A. Moore]]
[[File:PC12 sta 16 Alepisaurus ferox DSC 0012.jpg|thumb|A small lancetfish tattered from capture by a trawling net, photo by Dr. Jon A. Moore]]
In addition to a high degree of cannibalism and consumption of gelatinous foods, lancetfishes have also been documented with plastic refuse in their stomachs in the tropical north Pacific.<ref name=alepPlastic>{{cite journal|last1=Choy|first1=C.A.|last2=Portner|first2=E.|last3=Iwane|first3=M.|last4=Drazen|first4=J.C.|year=2013|title=Diets of five important predatory mesopelagic fishes of the central North Pacific|journal=Mar Ecol Prog Ser|volume=492|pages=169–184|doi=10.3354/meps10518|doi-access=free}}</ref> While the exact pathway of this ingestion is not yet clear, lancetfish likely have some affinity with the [[epipelagic]], but this could be by way of direct migration or migration of prey which had eaten plastic at the surface and returned to depth. One particularly bizarre example of this affinity for surface waters comes from a gut survey of lancetfish in the [[Indian Ocean]] where a large amount (24.1%) of floating [[macroalgae]] was documented in the stomachs of exclusively adult (>100&nbsp;cm) individuals. This is most likely indicative of the pursuit of evasive prey-types by larger lancetfish into epipelagic refuges.<ref name=alepIndia>{{cite journal|last1=Romanov|first1=E.V.|last2=Zamorov|first2=V.V.|year=2007|title=Regional feeding patterns of the longnose lancetfish (Alepisaurus ferox Lowe, 1833) of the western Indian Ocean|journal=Western Indian Ocean J. Mar. Sci|volume=6|pages=37–56}}</ref> The voracious appetite, low degree of prey selectivity, broad depth distribution, slow rate of digestion and ease of sampling via longline bycatch make lancetfishes useful platforms by which to study the greater ecology of deep mid-water fauna.<ref name=alepIndia>{{cite journal|last1=Romanov|first1=E.V.|last2=Zamorov|first2=V.V.|year=2007|title=Regional feeding patterns of the longnose lancetfish (Alepisaurus ferox Lowe, 1833) of the western Indian Ocean|journal=Western Indian Ocean J. Mar. Sci|volume=6|pages=37–56}}</ref>
<ref name=alepPlastic>{{cite journal|last1=Choy|first1=C.A.|last2=Portner|first2=E.|last3=Iwane|first3=M.|last4=Drazen|first4=J.C.|year=2013|title=Diets of five important predatory mesopelagic fishes of the central North Pacific|journal=Mar Ecol Prog Ser|volume=492|pages=169–184|doi=10.3354/meps10518|doi-access=free}}</ref>

In 2023, several lancetfish have washed up on the coastline of beaches of Oregon. While the fish tend to live in tropical or subtropical water, they often need to travel to Alaska's Bering Sea to find food. Beach-goers that see the fish have been requested to take a photo and tag the [[NOAA Fisheries]] West Coast region.<ref>{{Cite web |url=https://apnews.com/article/washed-up-weird-fish-fangs-oregon-beach-2f68e2ab46caa9a645d137e7f22735b7 |title='Freaky-looking' fanged fishes found on Oregon beaches |date=May 5, 2023 |last1=Bohrer |first1=Becky |last2=Dupuy |first2=Beatrice |publisher=[[AP News]] |access-date=May 7, 2023}}</ref>

==References==
{{Reflist}}

==External links==
{{Commons category|Alepisauridae}}
* [http://www.abdn.ac.uk/~nhi991/alepisaurus.htm Parasites of Lancetfish]
* [http://www.gma.org/fogm/Alepisaurus_ferox.htm Presence of Lancetfish in the Gulf of Maine]
* [http://fishesofaustralia.net.au/home/species/4022 Fishes of Australia.net lancetfish pictures and video links]

{{Taxonbar|from1=Q621219|from2=Q12782074}}

[[Category:Alepisauridae| ]]
[[Category:Extant Miocene first appearances]]
[[Category:Fish of Aruba]]