Family Alepocephalidae
Taxonomy: About 20 genera and possibly more than 90 species worldwide; currently, 16 genera with 37 described species recorded from Australian waters, although more than 50 species in 20 genera are thought to occur here.
Distribution, ecology and habitat: Worldwide in all oceans on the continental slope, oceanic ridges and rises, from just over the bottom to several hundred metres above; some in the bathy- or mesopelagic zones of the open ocean, one species known from epipelagic zone, a few known from the abyssal plains; in 100-5000 m, usually between 800-2500 m; some species widely distributed.
Characteristics:
Soft, fusiforme somewhat laterally compressed fishes, rarely elongate, eel-like or deep-bodied. Head small to very large, snout variable from short, obtuse to beak-like or tubular; mouth large, maxillae longer than eye diameter, very long in some, eyes moderate to large, most with large aphakic space (elliptical pupil extending in front of lens); dentition variable in size, shape and placement of teeth; gill openings usually wide, gill rakers long, numerous, upper elements of the two posterior gill-arches form an expanded pouch (crumenal organ) on each side involved in trapping food particles; no shoulder sac apparatus. Dorsal and anal fins usually far back on body, dorsal fin rarely in advance of anal fin, pelvic fins abdominal, caudal fin separate, forked, procurrent rays extending onto caudal peduncle, adipose fin absent. Scales cycloid, variable, head usually naked and covered in smooth, filmy black skin; body either naked or with large, thin, cycloid scales; photophores present in a few genera.
Size: Reach 70 cm SL, most 200-500 mm SL.
Food and feeding: Poorly known; reported food items include jellyfishes, salps, pyrosomes, ctenophores. A few species are predatory carnivores and some smaller species may feed on mesopelagic crustaceans, such as euphausiids, decapods and mysids.
Reproduction and early life history: Little known of reproduction; fecundity low, eggs large (between 2 and 8 mm in ovaries), most probably laid near the bottom, larval development direct.
Fisheries: Mostly seen as bycatch in deepwater trawl catches, but of little commercial importance and no specialised fisheries; some temperate and subtropical species occur in sufficient numbers to be sold in deep-sea fisheries.
Remarks: Many live in small groups or schools. Slickheads lack a swim bladder and rely on their soft, watery flesh for buoyancy; a few species may undertake diurnal migrations.
Australian species:
- Alepocephalus antipodianus (Parrott, 1948) Antipodean Slickhead CAAB 37114013
- Alepocephalus australis Barnard, 1923 Smallscale Slickhead CAAB 37114014
- Alepocephalus bicolor Alcock, 1891 Bicolor Slickhead CAAB 37114003
- Alepocephalus longiceps Lloyd, 1909 Longfin Slickhead CAAB 37114029
- Alepocephalus longirostris Okamura & Kawanishi, 1984 Longsnout Slickhead CAAB 37114043
- Alepocephalus owstoni Tanaka, 1908 Owston's Slickhead CAAB 37114042
- Alepocephalus triangularis Okamura & Kawanishi, 1984 Triangulate Slickhead CAAB 37114045
- Asquamiceps hjorti Koefoed, 1927 Barethroat Slickhead CAAB 37114004
- Aulastomatomorpha phospherops Alcock, 1890 Luminous Slickhead CAAB 37114038
- Bajacalifornia arcylepis Markle & Krefft, 1985 Network Slickhead CAAB 37114018
- Bajacalifornia calcarata (Weber, 1913) Brown Slickhead CAAB 37114019
- Bajacalifornia megalops (Lütken, 1898) Bigeye Slickhead CAAB 37114020
- Bathytroctes squamosus Alcock, 1890 Deepscale Slickhead CAAB 37114027
- Bathytroctes zugmayeri Fowler, 1934 Zugmayer's Slickhead CAAB 37114028
- Conocara kreffti Sazonov, 1997 Wrinkled Slickhead CAAB 37114033
- Conocara microlepis (Lloyd, 1909) Elongate Slickhead CAAB 37114034
- Conocara nigrum (Günther, 1878) Flathead Slickhead CAAB 37114036
- Einara macrolepis (Koefoed, 1927) Loosescale Slickhead CAAB 37114032
- Leptochilichthys microlepis Machida & Shiogaki, 1988 Smallscale Smoothhead CAAB 37114017
- Leptochilichthys pinguis (Vaillant, 1886) Vaillant's Smoothhead
- Leptoderma affinis Alcock, 1899 Eel Slickhead CAAB 37114039
- Mirognathus normani Parr, 1951 Beaked Slickhead CAAB 37114015
- Narcetes lloydi Fowler, 1934 Lloyd's Slickhead CAAB 37114016
- Narcetes stomias (Gilbert, 1890) Blackhead Slickhead CAAB 37114026
- Photostylus pycnopterus Beebe, 1933 Starry Slickhead CAAB 37114007
- Rouleina attrita (Vaillant, 1888) Softskin Slickhead CAAB 37114008
- Rouleina eucla Whitley, 1940 Eucla Slickhead CAAB 37114023
- Rouleina guentheri (Alcock, 1892) Bordello Slickhead CAAB 37114024
- Rouleina maderensis Maul, 1948 Madeiran Slickhead CAAB 37114025
- Rouleina squamilatera (Alcock, 1898) Sparkling Slickhead CAAB 37114001
- Talismania antillarum (Goode & Bean, 1896) Antillean Slickhead CAAB 37114009
- Talismania longifilis (Brauer, 1902) Longtail Slickhead CAAB 37114012
- Talismania mekistonema Sulak, 1975 Threadfin Slickhead CAAB 37114030
- Xenodermichthys copei (Gill, 1884) Bluntsnout Slickhead CAAB 37114002
References:
Ambrose, D.A. Alepocephalidae: slickheads, pp 224-233. In H.G. Moser (ed.) The early stages of fishes in the California Current region. California Cooperative Oceanic Fisheries Investigations (CalCOFI) Atlas No. 33. 1505 pp.
Sazonov, Y.I. & A.N. Ivanov. 1980. Slickheads (Alepocephalidae and Leptochilichthyidae) from the thalassobathyal zone of the Indian Ocean. Tr. Inst. Okeanol. Akad. Nauk. SSSR 110: 7-104.
Sazonov, Y.I., A.A. Balanov & V.V. Fedorov. 1993. Alepocephaloid fishes (Alepocephaloidei) from the western North Pacific Ocean. Tr. Inst. Oceanol. Russian Acad. Sci. 128: 40-68.
Sazonov, Y.I. & D.F. Markle. 1999. Family Alepocephalidae. In Carpenter, K.E. & V.H. Niem. Species identification guide for fisheries purposes. The living marine resources of the western central Pacific. Batoid fishes, chimeras and bony fishes. Part 1 (Elopidae to Linophrynidae). FAO, Rome.
Sazonov, Y.I. & A. Williams. 2001. A review of the alepocephalid fishes (Argentiniformes, Alepocephalidae) from the continental slope of Australia. J. Ichthyol. 41(Suppl. 1): S1-S36.