Alepisaurus ferox
Template:Short description Template:Speciesbox
Alepisaurus ferox, also known as the long snouted lancetfish, longnose lancetfish, or cannibal fish, is a species of lancetfish found in the ocean depths down to 1,830 m (6,000 ft).<ref name="FishBASE" /><ref name=":0">Template:Cite journal</ref> This species grows to Template:Convert in total length and a weight of Template:Convert.
The appellation cannibal fish stems from discoveries of partially-digested conspecifics in captured specimens.<ref name=":0" />
Habitat and ecosystemEdit
HabitatEdit
A. ferox lives in deep water oceans in the Western and Eastern Pacific, from the Aleutian Islands to Chile; the Western Atlantic, from the Gulf of Maine to the Gulf of Mexico, including the Caribbean Sea; in addition to the Northwest & Eastern Atlantic, Indian Ocean and China Sea.<ref name=FishBASE>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The longnose lancetfish can also be found as far north as Russia.<ref>Template:Cite journal</ref> This expansive geographic reach has caused for the species to be accidentally caught by some tuna fisheries.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Daily vertical migrations from the epipelagic all the way down to the mesopelagic or bathypelagic zones are undertaken to find food.<ref>Template:Cite journal</ref>
PredatorsEdit
The known predators for A. ferox include yellowfin tuna, opah, fur seals, Pacific cod, and salmon shark.<ref name=":1">Template:Cite journal</ref> Predators are known to change depending on the ocean region.<ref name=":1" />
Effect on ecosystemEdit
A. ferox is known for its predatory and prey behaviors in the south-western and central-western Pacific Ocean.<ref name=":0" /> In such regions, studies have been conducted to investigate the effects the longnose lancetfish has on the surrounding ecosystems—and whether those impacts are negative or positive for said ecosystems.<ref name=":3">Template:Cite journal</ref> When A. ferox was removed from these regions of the Pacific Ocean, there was a negative effect on the ecosystems that showed the importance of this species as both a predatory and prey type.<ref name=":3" />
Characteristics and behaviorEdit
AppearanceEdit
The dorsal fin has about three rays strongly exerted, beginning with the third or fourth ray. It is known to have a large mouth with two fangs. It is generally pale, iridescent, and dark around the dorsal fin; all of its fins are either dark brown or black.<ref name="FishBASE" />
The stomach of A. ferox is similar to that of the other species in the suborder of Alepisauroidea.<ref name=":2">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The gut of the A. ferox is a large, blind-sac that also has a very unique biological response to food.<ref name=":2" /> The stomach will store food in the stomach and slowly digest the contents, allowing for a more in depth understanding of the exact diet the A. ferox have.<ref name=":2" />
The large, sharp teeth of the lancetfish have two functions; breaking apart organisms too large to swallow whole and cutting trunk muscles to inhibit struggling. The teeth are not used for chewing otherwise.<ref name=":0" />
DietEdit
Longnose lancetfish diet varies depending on its inhabited area. Studies of diet variation have produced inconsistent results.<ref name=":0" /> They are known to prey on 98 component families; individuals may even consume man made materials, such as plastic.<ref name=":0" />
The longnose lancetfish is a migratory predator.<ref name=":3" /> It is known to travel to a depth of Template:Convert in order to hunt.<ref name=":3" /> A study in Suruga Bay, Japan, investigated the stomach contents of various specimens that had washed ashore and found, along with indigestible materials, traces of marine species of the photic and aphotic zones.<ref name=":0" /> This study showed that the longnose lancetfish is a deep sea diving species capable of migrating across different sea depths.<ref name=":0" />
As aforementioned, the longnose lancetfish is referred to as the cannibal fish due to its conspecific predation habits. The extent of cannibalistic behavior depends on the availability of non-conspecific prey, with frequency of these patterns ranging from 0 to 45.5%.<ref name=":3" /> Such is contingent upon the availability and ease of finding other prey.<ref name=":3" /> Size is an influencing factor; small lancetfish will not resort to cannibalism as quickly as larger fish.<ref name=":3" />
ReproductionEdit
The fish are hermaphroditic: they have both male and female reproductive parts at the same time.<ref>Template:Cite journal</ref> Unlike other hermaphroditic fishes, A. ferox has two distinct testicular lobes that are independent from the ovarian region.<ref name=":4">Template:Cite journal</ref> This species also has an absence of a pair of diverticulae in the female reproductive section, which in other hermaphrodites is used for spermatophore uptake.<ref name=":4" />
Human impactEdit
Plastic consumptionEdit
Plastic is ingested by approximately 30% of all A. ferox.<ref name=":5">Template:Cite journal</ref> Macroplastic fragments and rope fragments were the most commonly found plastic in the stomach contents with white and clear colored plastics seeming to be favored.<ref name=":5" />
BycatchEdit
A. ferox is commonly caught as bycatch for longline fisheries and is never the intended target. In the Philippines, studies of longline tuna fisheries revealed that they usually caught more A. ferox than any tuna.<ref>Template:Citation</ref> A. ferox also accounts for 2% of all bycatch by circle and j hook longline fisheries in the Bay of Bengal.<ref>Template:Cite journal</ref> Survival of being bycatch in these types of nets is low — only one third of A. ferox survive.<ref>Template:Cite journal</ref>