© Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia Full citation Baker, J.L. (2009) Marine Species of Conservation Concern in South Australia: Volume 1 - Bony and Cartilaginous Fishes. Report for the South Australian Working Group for Marine Species of Conservation Concern. J. Baker (consultant); Science and Conservation Division, and Coast and Marine Conservation branches of S.A. Department for Environment and Heritage (DEH); Marine and Coastal Community Network of S.A. (MCCN), and Threatened Species Network (TSN). Web version published by Reef Watch, South Australia.

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Threefin Velvetfish

Family Name:	Aploactinidae
Scientific Name:	Neoaploactis tridorsalis Eschmeyer and Allen, 1978
Recommended Status in S.A:	Data Deficient
Rationale:  The species is included here because (i) N. tridorsalis is a small benthic fish species that is rarely seen, and was previously known from very few specimens, but is possibly locally abundant in some areas; (ii) its presence in South Australia is unusual, considering the mainly sub-tropical distribution of this species; (iii) the shallow distribution of the Threefin Velvetfish (e.g. less than 10m) and benthic nature in soft-bottom habitats, may make it susceptible to decline from habitat impacts in some areas; and (iv) there is very little information known about the distribution, biology (particularly growth, longevity and reproduction), habits, population dynamics, and relative abundance of this species, in any part of its known geographic range. The species is very small, cryptic, and is not likely to be seen unless specifically searched for. It is possible that the species (or a close relative) might be more widely distributed than current records suggest, and surveys would be required to determine if that is the case. Given the lack of records, and paucity of information about this species, it is considered to be Data Deficient in status at the present time.

Page Contents

Current Conservation Status

No listings known

Distribution

General

Specimens reported to be Neoaploactis tridorsalis have been recorded from One Tree Island in the Capricorn Group islands (southern Great Barrier Reef) in Queensland; Rottnest Island, Kingston Reef and Shark Bay in Western Australia; and from South Australia (Eschmeyer and Allen, 1978; Poss, in Gomon et al., 1994; West Australian Museum records, cited by W. A. Museum, 2003).
The species has more recently been recorded from the Loyalty Islands in New Caledonia (Kulbicki and Williams, 1997, cited in Froese and Pauly, 2007).

South Australia

Previously in S.A., the species was known from a single record, collected in Encounter Bay in 1981 (by B. Hutchins, with identity confirmed by S. Poss) (W.A. Museum record, cited by Poss, in Gomon et al., 1994; B. Hutchins, W.A. Museum, pers. comm., 2006).  Presently in South Australia, the species is known from 6 museum specimens in 4 records, plus photographs from two other localities, but is likely to be more abundant than current records indicate. In addition to the Encounter Bay specimen, other examples include three specimens collected in 1890 near Semaphore in northern metropolitan Gulf St Vincent (GSV), and previously misidentified as juvenile Aploactisoma milesii (South Australian Museum record F01549, cited by R. Foster, pers. comm., 2006); a specimen taken in 2006, from 3-4km off Outer Harbour in metropolitan GSV (SAM specimen, collected by R. Gannon and identified by R. Foster), and a single, undated specimen, from the Franklin Harbour area in Spencer Gulf (South Australian Museum record F10479, cited by R. Foster, pers. comm., 2006). In addition, there is a photograph taken by R. Kuiter, of juvenile Neoaploactis tridorsalis under Rapid Bay Jetty, in south-eastern GSV (cited by M. Gomon, Museum of Victoria, pers. comm., 2006); and photographs of specimens sighted on several occasions in recent years, under Edithburgh Jetty in south-western GSV (photographs by J. Lewis, verified by J. Johnson, Queensland Museum, 2007).
Both larvae and small specimens have been recorded in southern Gulf St Vincent (data by B. Bruce, CSIRO, and R. Kuiter, Zoonetics, cited by M. Gomon, pers. comm., 2006).
There is a record of the species from the central Great Australian Bight, near the W.A. / S.A. border, collected using epibenthic sled, in 1995 (R. Foster, South Australian Museum, pers. comm., 2006).

Habitat

Threefin Velvetfish is found on sand or rubble bottoms near reefs (Western Australian Museum, 2003). The species has been reported from both rocky reefs and soft-bottom trawling grounds (Randall et al., 1990, cited in Froese and Pauly, 2007).
Most specimens are known from shallow water (less than 10m), but there is a specimen from the Great Australian Bight, taken at 54m (R. Foster, South Australian Museum, pers. comm., 2006).

Notes on the Biology

Growth

This small species with spinous body scales grows to around 4cm or 5cm (Randall et al., 1990, cited in Froese and Pauly, 2007; Poss, in Gomon et al., 1994).

Reproduction

Little is known of spawning mode of velvetfishes (Leis, 2005). A few larvae of fishes in this family have been described (Kojima, 1988; Leis and Carson-Ewart, 2000; Leis et al., 2004, cited by Leis, 2005), and specialisations to pelagic life include the extremely large, early forming pectoral fins, and the extensive head spination (the latter of which is largely retained by adults) (Leis, 2005).
B. Bruce (CSIRO, pers. comm., cited by M. Gomon, Museum of Victoria, 2006) has found larvae to be abundant in South Australia.

Vulnerable Characteristics of the Species and Threatening Processes

The inshore distribution (which is typical of members in the Aploactinidae), benthic nature, and habitat preference of this species (e.g. sand and rubble near reef, and possibly other soft bottom habitats) may make localised populations susceptible to decline from habitat impacts in some areas (e.g. sedimentation and pollutants from coastal effluent discharge; or physical loss and sedimentation of habitat from trawling, dredging, channel clearing etc).
The species is reported from soft-bottom trawling grounds (Randall et al., 1990, cited in Froese and Pauly, 2007). Given the strong site association and limited mobility of this species, trawling in upper continental shelf waters might be a threatening process in some parts of the range. However, to date, there are virtually no catch records from trawling; hence populations may be a low risk from this process (M. Gomon, Museum of Victoria, pers. comm., 2006).
There is no knowledge of reproduction in this species. If dispersal is low, and recruitment of the next generation is localised, then that mode of reproduction may increase the vulnerability of populations to site-specific impacts.

Research and Management Requirements

Specimens of Threefin Velvetfish in South Australia should be examined and compared, if possible, with those from the tropical and sub-tropical parts of the range. It is not known whether the specimens found in S.A. are the same species as those from Queensland, and New Caledonia, for example.
Surveys in suitable habitat (e.g. shallow subtidal sand and rubble, near reefs) should be undertaken to determine the relative abundance of Threefin Velvetfish in southern Australia, including South Australia.
There is very little information known about the distribution, biology (particularly growth, longevity and reproduction), habits, population dynamics, and relative abundance of this species, in any part of its known geographic range.
In South Australia, any future presence of this species in prawn trawl bycatch should be recorded over space and time.
Dredging and channel clearing programs need to be conscious of the potential presence of cryptic, benthic fish species such as Velvetfishes.

Other Information

Previously, the species was reported to be very rare (Poss, in Gomon et al., 1994), and was known only from a few specimens in museum collections, mostly from tropical and subtropical areas. However, it is possible that the species would be overlooked during surveys, due to its small size and apparently cryptic appearance. A recent sighting (by R. Kuiter, cited by M. Gomon, Museum of Victoria, pers. comm., 2006) of abundant small specimens of N. tridorsalis under Rapid Bay Jetty in South Australia may indicate that the species (or a close relative in southern waters) is more common and widespread than was previously thought.