Snake mackerel

The snake mackerel has a very long, slender, laterally compressed body. It has a long, pointed head, measuring 17–18% of the standard length, and a large mouth with the lower jaw protruding beyond the upper. Both jaws are densely packed with sharp teeth; the first few teeth in the upper jaw are enlarged into fangs. The pectoral fins contain 12–15 rays; the pelvic fins are tiny and located beneath the pectorals, containing 1 small spine and 3–4 rays. There are two dorsal fins; the first is long and spiny, and is followed immediately by the second, which contains 1 tiny spine and 11–14 soft rays. The anal fin originates opposite the second dorsal fin and consists of 2 free spines followed by 1 spine and 10–12 rays. The dorsal and anal fins are followed by 6–7 finlets. There are two lateral lines, with the upper running to the rear of the first dorsal fin and the lower running to the caudal peduncle. The scales are mostly absent. The coloration is metallic brown, with dark fins. This species grows to in length. ==Behaviour==

Adult snake mackerels conduct a diel vertical migration, staying in deeper water during the day and rising to the surface at night to feed. The young and juveniles also migrate vertically but in the opposite direction, staying near the surface during the day and moving deeper at night. This species feeds on squid, pelagic crustaceans, and bony fishes such as lanternfishes, flying fishes, sauries, and mackerel. ==Human interaction==

The snake mackerel is caught as bycatch in the tuna longline fishery and is of minor commercial importance. It is marketed frozen or in sausages and fish cakes. A night-time encounter with Gempylus species in the open sea is described by Thor Heyerdahl in the accounts of the Kon-Tiki expedition. After a member of the raft expedition was awoken by a mysterious fish landing on his sleeping bag, the crew member caught a long thin fish that was "over three feet long, as slender as a snake, with dull black eyes and long snout with a greedy jaw full of long sharp teeth. The teeth were sharp as knives and could be folded back into the roof of the mouth to make way for what is swallowed." Later Thor Heyerdahl notes: "Only the skeleton of a fish like this one had been found a few times on the coast of South America and the Galapagos Islands; ichthyologists ... thought it lived at the bottom of the sea at a great depth, because no one had ever seen it alive. But if it lived at a great depth, this must at any rate be by day, when the sun blinded the big eyes. For on dark nights Gempylus was abroad high over the surface of the sea; we on the raft had experience of that". ==References==