Longnose lancetfish inhabit all of the planet's oceans. They are found most commonly in tropical and sub-tropical waters, but have a very wide distribution. Their range includes the eastern Pacific, from the Aleutian Islands to Chile; the western Pacific, from Japan to Australia, New Zealand, and New Caledonia; the eastern Atlantic, from Greenland to the Gulf of Mexico and the Caribbean; the western Atlantic, as far north as Iceland; the Mediterranean Sea; and the Indian Ocean, off the coasts of Natal, South Africa and the Maldives (84°N-57°S, 180°W-180°E). ("Fishes of the NE Atlantic and the Mediterranean: Lancet-fish (Alepisaurus ferox)", 2012; Bailly, 2013; Froese and Luna, 2012; Paxton, 2012)
Longnose lancetfish can be found from the epipelagic through the bathypelagic zones (most commonly in the mesopelagic zone), at depths of 0-1850 meters. Although they are most common in subtropical and tropical waters, they may also migrate to subarctic areas to spawn and feed without competition. ("Alepisaurus ferox", 2012; Froese and Luna, 2012; Orlov and Ul'chenko, 2002; Paxton, 2012)
Longnose lancetfish are the largest species in the family Alepisauridae, growing up to 215 cm in length (150 cm, on average) and 9 kg in weight (1.3-3.2 kg, on average). Their bodies are elongate, slightly compressed, and typically a pale, iridescent silver in color. Their coloration is darker dorsally and towards the keel and all of the fins are dark brown or black. These fish are scaleless, and their skin is covered with pores. The swim bladder is absent. Longnose lancetfish have a distinct, sail-like dorsal fin, with 30-45 rays. The caudal fin is deeply forked, with a prolonged upper lobe. The anal fin has a deep, concave profile, and has 13-18 rays. The pelvic fins are located mid-body, and the pectoral fins are relatively long. These fish have 46-52 vertebrae. Longnose lancetfish are not sexually dimorphic; individuals have both male and female genitalia, suggesting that they are hermaphroditic. ("Fishes of the NE Atlantic and the Mediterranean: Lancet-fish (Alepisaurus ferox)", 2012; Bray, 2013; Digital Fish Library, 2009; Froese and Luna, 2012; Lavett Smith and Atz, 1973; Varghese, et al., 2010)
Longnose lancetfish have large mouths and a long palatine bone, with highly developed teeth (1-2 anterior fangs and 3 smaller posterior fangs, as well as 7-10 triangluar posterior teeth). In addition to these, there are small teeth set into the upper jaw, and 1 large anterior fang, 10 small canines, 3 posterior fangs, and 10-15 smaller, triangular teeth set into the lower jaw. ("Fishes of the NE Atlantic and the Mediterranean: Lancet-fish (Alepisaurus ferox)", 2012; Bray, 2013)
Little is currently known about the development of longnose lancetfish. specifically. Existing evidence suggests that these fish follow a standard developmental progression, advancing from an egg to a planktonic stage, to a pelagic larval stage, before finally achieving their adult form. ("Alepisaurus ferox", 2012; Bailly, 2013; Bray, 2013; Froese and Luna, 2012)
Adolescent longnose lancetfish are synchronous hermaphrodites, with individuals possessing both testes and ovaries. Separate sperm ducts are located dorsally to the ovaries, and there are distinct, separate, external openings for both sperm and oviducts. Fertilization takes place externally, though it is not known if self-fertilization is common or even possible; it is also not clear if the synchronous hermaphroditic state is present in adults as well as adolescents. (Bailly, 2013; Bray, 2013; Froese and Luna, 2012; Lavett Smith and Atz, 1973)
The age at which longnose lancetfish reach sexually maturity is currently unknown; the oviducts remain enclosed by connective tissue until maturity is reached. Adolescents are known to be synchronous hermaphrodites, although it is not clear if this state persists into adulthood. No information regarding number of offspring or length of mating season is currently available for this species, although they have been recorded spawning in May off the coast of California, and young have been caught off the coast of Bermuda. ("Alepisaurus ferox", 2012; "Fishes of the NE Atlantic and the Mediterranean: Lancet-fish (Alepisaurus ferox)", 2012; Bray, 2013; Paxton, 2012)
There is currently no information regarding the lifespan or longevity of this species. ("Alepisaurus ferox", 2012)
Longnose lancetfish have no well-developed deep red muscles, suggesting that they are incapable of maintaining high cruising speeds; rather, their muscle tissue is largely made up of white muscle, which is responsible for short bursts of speed and motion. With their high dorsal fin and large caudal fin, longnose lancetfish are highly maneuverable. There are conflicting reports regarding this species' behavior, with some researchers stating that individuals are mainly nocturnal, while others state that they are known to be daytime feeders. (Froese and Luna, 2012; Potier, et al., 2007; Romanov and Zamorov, 2002)
There is no data suggesting that individuals of this species maintain a well-defined home range or territory. (Froese and Luna, 2012)
There is little data available regarding longnose lancetfish communication abilities or any special sensory organs. Like most fishes, they have eyes for visual perception, a lateral line system for detecting vibrations in the water, olfactory receptors for detecting odors and tastes, and inner ears with which they can detect sounds. (Bond, 1996)
Longnose lancetfish are reportedly opportunistic, daytime feeders (although some researchers have stated that these fish are nocturnal). They are voracious hunters of epipelagic and mesopelagic prey and have been described as ambush-type hunters. Crustaceans are a main prey item, and feeding studies show that the swimming crab, Charybdis smithii, is preferred by some populations, followed by cephalopods, tunicates, and bony fishes. They are also known cannibals, particularly when other prey is unavailable. Longnose lancetfish have large mouths and sharp teeth to aid in catching prey. The stomach contents of these fish indicate that they migrate through and feed at a variety of depths. (Froese and Luna, 2012; Kubota and Uyeno, 1970; Potier, et al., 2007; Romanov and Zamorov, 2002; Romanov, et al., 2008; Varghese, et al., 2010)
Known predators of longnose lancetfish include opah, sharks, yellowfin tuna, albacore, pacific cod, bigeye tuna, swordfish, fellow longnose lancetfish, and fur seals. (Bailly, 2013; Froese and Luna, 2012; Martin, 2003; Romanov, et al., 2008; Varghese, et al., 2010)
This species serves as an intermediate link in oceanic trophic systems, feeding on smaller fishes and invertebrates, while serving as prey to larger fish species. Longnose lancetfish are also potential intermediate and terminal hosts for a number of parasitic organisms, such as nematodes, cestodes, and trematodes. (Bray, 2004; Jakob and Palm, 2006; Scholz, et al., 1998)
Longnose lancetfish are a valuable resource for scientific research, particularly on deep sea food chains, due to the well-preserved nature of prey items in their stomachs. (Fujita and Hattori, 1976; Potier, et al., 2007)
Longnose lancetfish are often taken as bycatch in commercial longline tuna fisheries, although they are generally unsuitable for commercial use. (Froese and Luna, 2012)
Longnose lancetfish are categorized as a species of least concern by the International Union for Conservation of Nature. They are not considered to be endangered or threatened in any part of their distribution. (Paxton, 2012)
Zack Clever (author), Bridgewater College, Rachel Lee (author), Bridgewater College, Andrew Shepherd (author), Bridgewater College, Tamara Johnstone-Yellin (editor), Bridgewater College, Jeremy Wright (editor), University of Michigan-Ann Arbor.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
living in the southern part of the New World. In other words, Central and South America.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.
active at dawn and dusk
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
fertilization takes place outside the female's body
union of egg and spermatozoan
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.
Found in northern North America and northern Europe or Asia.
Animals with indeterminate growth continue to grow throughout their lives.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
an animal that mainly eats fish
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.
mainly lives in oceans, seas, or other bodies of salt water.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
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