Family Carapidae
Taxonomy: Seven genera and 31 species in two subfamilies; 6 genera with 16 described species collected from Australian waters.
Distribution, ecology and habitat: Worldwide in all tropical and subtropical oceans; mostly benthic in shallow to moderately deep waters on the continental slope to 2000 m; (rarely pelagic or epi-benthic in deepwater).
Characteristics:
Adults - body long, slender, tapering, compressed to rounded; head large, eye subequal to snout length, mouth large, terminal, jaws extending well beyond eye, teeth either fang-like or heart-shaped; supramaxilla absent; gill openings wide, extending far forward; opercular bones without spines. Dorsal and anal fins long-based, anus and anal-fin origin far forward, usually below pectoral fin base; caudal fin usually absent, dorsal and anal fins continuous, tapering to a firm tip, allowing tail-first entry to host; anal-fin rays longer that those of dorsal fin; pectoral fin shorter than head, pelvic fins absent in most, or reduced to a single ray. Scales absent.
Size: to 36 cm.
Food and feeding: Carnivorous or parasitic on host - some species leave the host to feed at night, while others are parasitic, always remaining inside to feed on the internal organs of the host.
Reproduction and early life history: Oviparous, eggs of most undescribed, reproduction and early life history poorly known. Eggs small, up to 1 mm in length, oval or ellipsoid, laid in a gelatinous raft, single oil globule present, yolk segmented. Larvae conspicuous, extremely elongate, 2.6-6.0 mm at hatching, with two distinct larval stages - the first, a planktonic vexillifer stage, characterized by larvae possessing a peculiar long, movable, ornamented predorsal filament or vexillumexillum; the second tenuis stage is demersal (possibly absent in the free-living species). In the tenuis stage, the vexillum is absent, the total length is reduced and individuals can enter the host at this stage.
Fisheries: Taken as bycatch in some sea cucumber fisheries, but of no commercial importance.
Remarks: The unique assocation of pearlfishes and invertebrate hosts may include male-female pairing within the same host, cannibalism and parasitism on various internal organs such as the gonads or respiratory tree. In addition, several species may be commensal on the same holothurian host.
Australian species:
- Carapus mourlani (Petit, 1934) Star Pearlfish CAAB 37229006
- Echiodon anchipterus Williams, 1884 Closefin Pearlfish CAAB 37229014
- Echiodon rendahli (Whitley, 1941) Messmate Fish CAAB 37229003
- Encheliophis boraborensis (Kaup, 1856) Pinhead Pearlfish CAAB 37229007
- Encheliophis gracilis (Bleeker, 1856) Graceful Pearlfish CAAB 37229001
- Encheliophis homei (Richardson, 1846) Silver Pearlfish CAAB 37229002
- Encheliophis vermicularis Müller, 1842 Worm Pearlfish CAAB 37229009
- Encheliophis vermiops Markle & Olney, 1990 Pygmy Pearlfish CAAB 37229015
- Eurypleuron cinereus (Smith, 1955) Wide-rib Pearlfish CAAB 37229008
- Onuxodon fowleri (Smith, 1955) Fowler's Pearlfish CAAB 37229013
- Onuxodon margaritiferae (Rendahl, 1921) Cucumber Pearlfish CAAB 37229004
- Onuxodon parvibrachium (Fowler, 1927) Oyster Pearlfish CAAB 37229010
- Pyramodon lindas Markle & Olney, 1990 Blackedge Pearlfish CAAB 37229016
- Pyramodon punctatus (Regan, 1914) Dogtooth Pearlfish CAAB 37229011
- Pyramodon ventralis Smith & Radcliffe, 1913 Pallid Pearlfish CAAB 37229012
References:
Gordon, D.J., D.F. Markle & J.E. Olney. 1984. Ophidiiformes: Development and relationships, pp. 308-319 In Moser, H.G., Richards, W.J. Cohen, D.M., Fahay, M.P., Kendall, Jr, A.W. & Richardson, S.L. (eds.) Ontogeny and systematics of fishes. American Society of Ichthyologists and Herpetologists, Special Publication 1, Lawrence, Kansas. 760 pp.
Govoni, J.J., Olney, J.E., Markle, D.F. & Curtsinger, W.R., 1984. Observations on Structure and Evaluation of Possible Functions of the Vexillum in Larval Carapidae (Ophidiiformes). Bull. Mar. Sci. 34: 60–70.
Markle, D. F. & Olney, J.E. (1990). Systematics of the pearlfishes (Pisces: Carapidae). Bull. Mar. Sci. 47(2): 269–410.
Nielsen, J.G. 1999. Family Carapidae: Pearlfishes, pp. 1978 In Nielsen, J.G., Cohen, D.M., Markle, D.F. & Robins, C.R. (Eds.), FAO Species Catalogue, Vol. 18, Ophidiiform Fishes of the World (Order Ophidiiformes), An annotated and illustrated catalogue of pearlfishes, cusk-eels, brotulas and other ophidiiform species known to date. FAO Fisheries Synopsis No. 125 Vol. 18 178 pp.
Olney, J.E. 2006. Ch. 50 Carapidae: Pearlfishes, p. 749 In W.J. Richards (ed). Early Stages Of Atlantic Fishes: An Identification Guide For The Western Central North Atlantic. CRC Press, Taylor and Francis Group, Boca Raton, FL, 2640 pp.
Olney, J.E., J.M. Leis & D.S. Rennis. 2000. Carapidae (Pearlfishes), pp.104-108 In Leis, J.M. & B.M. Carson-Ewart. (eds). The larvae of Indo-Pacific coastal fishes. An identification guide to marine fish larvae. (Fauna Malesiana Handbooks 2). E.J. Brill, Leiden. 870 pp.
Parmentier, E., G. Castillo, M. Chardon & P. Vandewalle. 2000. Phylogenetic analysis of the pearlfish tribe Carapini (Pisces: Carapidae). Acta Zool. (Stockh.) 81: 293-306.
Robertson, D.A. 1975. Planktonic stages of the Teleost family Carapidae in eastern New Zealand waters. N. Z. J. Mar. Freshw. Res. 9(3): 403-409.
Trott, L.B. 1970. Contributions to the biology of carapid fishes (Paracanthopterygii : Gadiformes). Univ. Calif. Publ. Zool. 89: 1-41.
Williams, J.T. 1983. Synopsis of the pearlfish subfamily Pyramodontinae (Pisces: Carapidae). Bull. Mar. Sci. 33(4): 846-854.
Williams, J. T. 1984. Studies on Echiodon (Pisces: Carapidae), with description of two new Indo-Pacific species. Copeia 1984(2): 410-422.