Cyema atrum
FAMILY
Cyematidae
TAXONOMY
Cyema atrum Günther, 1878, South Pacific, Challenger station 1,770 ft (539 m); Antarctic, Challenger station 948; 9,000; and 10,800 ft (289; 2,743; and 3,292 m).
OTHER COMMON NAMES
English: Bobtail eel, deepwater eel; Danish: Korthalet ål; Finnish: Nuoliankerias.
PHYSICAL CHARACTERISTICS
This species has a rather striking appearance that is quite different from that of other saccopharyngiforms. Adults are black in coloration. This species is scaleless, like all members of the order. The eyes are very small. The jaws are thin and long, with numerous very fine teeth, and the jaws curve slightly away from each other at their tips. The dorsal and anal fin rays become progressively more elongated toward the rear of the body and extend well past very short caudal rays; the effect is that in side view the fish looks like an arrow! It is a small species, with a maximum reported size of about 6.3 in (160 mm).
DISTRIBUTION
It has been reported from all oceans between about 70° north and 55° south. Most collections have been from the Atlantic and Pacific Oceans.
HABITAT
The species is oceanic, lower mesopelagic to bathypelagic. Although it has been reported from collections made as shallow as 1,148 ft (350 m), most records are from depths exceeding 4,921 ft (1,500 m).
BEHAVIOR
Nothing is known.
FEEDING ECOLOGY AND DIET
There has been little research on the feeding habits of this eel. Because of its jaw structure, it is suggested that the species feeds on comparable prey types and in a fashion similar to that of the anguilliform eels of the family Nemichthyidae, commonly known as snipe eels. Nemichthyids use their thin, recurved jaws to feed on crustacean shrimps, especially those in the family Sergestidae. Predators of this species are unknown.
REPRODUCTIVE BIOLOGY
Unlike the other saccopharyngiforms, there is no apparent sexual dimorphism in adults. No other reproductive data have been reported for this species. The leptocephalus stage is rather distinctive; the deep oval body has a very small pointed head and a pointed caudal extension. These features grow a bit larger than in other saccopharyngiform leptocephali, with a maximum recorded total length of 2.8 in (70 mm).
CONSERVATION STATUS
Not threatened.
SIGNIFICANCE TO HUMANS
None known.
