Family Bathylaconidae

Taxonomy: Small family with 2 genera and 4 species; a single genus and species known from Australian waters.

Distribution, ecology and habitat: Circumglobal in tropical and temperate latitudes on the continental slope; meso- and bathypelagic to 4500 m, usually below 1000 m.

Characteristics:
Moderately elongate fishes, head moderate to large, mouth very large, eye large with prominent rostral aphakic aperture and comma-shaped lid fold in front of eye; premaxilla minute, maxilla extending well beyond eyes, both with thin, pointed teeth; lower jaw with normal conical teeth in one genus, modified into low semicircular plates in other giving toothless appearance; upper branchiostegal rays broad, forming part of gill cover, tongue present; upper elements of posterior 2 gill arches form an expanded pouch (crumenal organ) on each side. Single dorsal fin originating on posterior half of body slightly in advance of anal fin, pelvic fins below anterior part of dorsal fin, pectoral fins small, low on body, adipose fin absent. Head naked with large lateral line pores, lateral line running along body midline, body scales large, cycoid. No photophores, swimbladder absent. Body generally black or dark brown in colour, head darker than body.

Size: To over 40 cm SL.

Food and feeding: Unknown, although some species are thought to be fast-swimming predators.

Reproduction and early life history: Little known of reproduction, oviparous with pelagic eggs and larvae; eggs large, developing eggs in gonads to 2.7 mm, larval development direct.

Fisheries: No commercial importance, but occasionally caught as bycatch in commercial fisheries.

Remarks: Free swimming, most species live close to the bottom.

Australian species:

References:

Ambrose, D.A. 1984. 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.

Iwamoto, T., J.E. McCosker & O. Barton. 1976. Alepocephalid fishes of the genera Herwigia and Bathylaco, with the first Pacific record of H. kreffti. Jpn. J. Ichthyol. 23(1): 55-59.

Johnson, G.D. & C. Patterson. Ch. 12: Relationships of lower euteleostean fishes, pp. 251-332, In Stiassny, M.L.J., Parenti, L.R., & Johnson, G.D. (eds) 1996. Interrelationships of Fishes. 251-332. San Diego: Academic Press, 496 pp.

Nielsen, J.G. & V. Larsen. 1968. Synopsis of the Bathylaconidae (Pisces, Isospondyli) with a new eastern Pacific species. Galathea Rept. 9: 221-238, pls. 13-15.

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.