Saccopharynx ampullaceus
FAMILY
Saccopharyngidae
TAXONOMY
Ophiognathus ampullaceus Harwood, 1827, NW Atlantic Ocean, 32°20'N, 30°16'W, 0–6,234 ft (0–1,900 m). Neotype: ISH 3288/79. Original locality 62°N, 57°W. Neotype selected by Nielsen and Bertelsen (1985).
OTHER COMMON NAMES
English: Pelican fish; Danish: Slugål; Finnish: Ahmattiankerias; Icelandic: Pokakjaftur; Polish: Gardzielec.
PHYSICAL CHARACTERISTICS
The body is attenuated and very flabby, with poorly ossified bones and weakly developed muscles. The most striking attributes are tiny eyes that function as light detectors; a greatly enlarged mouth with numerous slightly recurved teeth; an elongated stomach region, with the posterior end of the abdomen clearly demarcated from the tail, and an extremely long tail (about 75% of body length), with an elongated caudal filament that terminates in a "caudal organ" believed to be luminescent. Because of the delicacy of the body, the filaments often are broken off in captured specimens. The body is scaleless. The largest intact specimen measured 5.2 ft (1.6 m), although much of the body length consists of the elongated whiplike tail and caudal filament.
DISTRIBUTION
This species is the best known of the genus. It has been collected only from the North Atlantic Ocean between 10° and 65° north latitude.
HABITAT
The gulper eel is oceanic and bathypelagic. Only juveniles have been captured at depths of less than 2,624 ft (800 m). It is believed that adults typically reside deeper than 6,561 ft (2,000 m).
BEHAVIOR
Because of the great depths of its habitat, aspects of the behavior of this species are largely the subject of conjecture.
FEEDING ECOLOGY AND DIET
The species is piscivorous. Relatively few saccopharyngids have been recovered with intact stomach contents, but in all cases various fish species were the prey. The gulper eel has an extremely distensible stomach, allowing it to ingest very large prey. Because of its weak skeleton and body muscles, it is believed to be a very poor swimmer. It is thought to lure prey within range by means of the luminescent caudal organ, which it may suspend in the water near its mouth. The jaw muscles are the only well-developed muscles and probably allow the gulper eel to suck its prey into the large mouth by quickly opening the jaws. Predators are unknown.
REPRODUCTIVE BIOLOGY
Males and females are sexually dimorphic. Sexually mature males show extreme degeneration of the jaws, along with a loss of teeth and reduction in abdominal size. In addition, the eyes become somewhat enlarged, and the nasal apparatus is significantly enlarged. It has been suggested that males locate females by tracking pheromone (scent) trails released by the females. As with numerous eel species as well as some other deep-sea fish species, reproduction is thought to be a terminal event. As with eels in general, larval gulper eels have a leptocephalus, a ribbon-like transparent stage. Relatively few leptocephali have been collected, but all are deep-bodied and small, with a total length of 1.47–1.9 in (40–50 mm).
CONSERVATION STATUS
Not threatened.
SIGNIFICANCE TO HUMANS
None known.
