© 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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Wasp-spine Velvetfish

Family Name:	Aploactinidae
Scientific Name:	Acanthosphex leurynnis (Jordan & Seale, 1905)
Recommended Status in S.A:	Data Deficient
Rationale:  The species is included here because (i) A. leurynnis appears to be uncommon throughout its purported range, with few specimens known, particularly from southern Australia; (ii) the records from South Australia (and one from temperate W.A.) are unusual, due to the mainly tropical distribution of this species; (iii) the habitat preferences of Wasp-spine Velvetfish make it susceptible to capture in trawls, but the potential population impacts are not known; (iv) the shallow distribution of this species may make it susceptible to decline from habitat impacts in some areas, but more information is required; and (v) there is very little known about the distribution, biology (particularly growth, longevity and reproduction), habits, population dynamics, and relative abundance of this species. The Wasp-spine Velvetfish 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

Global

Acanthosphex leurynnis is known mainly from tropical Asian countries, including South China Sea near Hong Kong, Gulf of Thailand, southeast India, Indonesia, Viet Nam and eastern Papua New Guinea (Ramaiyan and Rao, 1970; Vidthayanon and Bettencourt, 1988; Anonymous, 1993; Poss, 1999; Johnson, 2004; Poss, cited in Froese and Pauly, 2007; Matsuura and Kimura, 2006). There are few specimens from Australia (see below).
The type specimen is from Hong Kong, listed as Prosopodasys leurynnis (Jordan and Seale, 1905; National Museum of Natural History data, cited in Eschmeyer, 2004).

Australia

In Australia, there are very few records. Specimens identified as Acanthosphex leurynnis have been recorded from Repulse Bay and Whitsunday I. in Queensland; a site NE of Goulburn I. in the Arafura Sea off Northern Territory; the Perth area in Western Australia (Johnson, 2004), and Spencer Gulf and Gulf St Vincent in South Australia (see below).

South Australia

To date, there are few records from South Australia, of specimens that have been identified as Acanthosphex leurynnis. Examples include 3 museum specimens that were collected from Spencer Gulf in 1898 (South Australian Museum record F10478, cited by R. Foster, pers. comm., 2006), and recent shallow trawl survey records in Gulf St Vincent and Spencer Gulf (R. Saunders, SARDI, pers. comm., 2008).
It is presumed that this very small, cryptic fish is usually overlooked in benthic surveys, and no targeted surveys have been undertaken to date.

Habitat

Very little information about the habitat has been recorded. Vidthayanon and Bettencourt (1988, cited in Froese and Pauly, 2007) reported that the species may inhabit interstices on rocky and coral-rubble bottoms, bottoms with coralline algae, and may also be found among vegetation.
A specimen from Queensland was collected from trawling over seagrass (Queensland Museum record I.23965, cited by Johnson, 2004). In South Australia, the species has been trawled at about 8m, in mixed habitat that includes some seagrass (R. Saunders, SARDI, pers. comm., 2008)
In southern Vietnam, a specimen verified (by S. Poss) as being A. leurynnis, was recorded in a mangrove estuary (Californian Academy of Sciences record, cited by Anonymous, 1993).
The depth range has not been published, but specimens have been collected from depths that range from the intertidal / shallow subtidal (e.g. mangroves), to deeper waters of the upper continental shelf (e.g. trawl specimen, from 60m) (Johnson, 2004).

Notes on the Biology

Growth

The standard length of this small fish is less than 3cm (Vidthayanon and Bettencourt, 1988) and specimens smaller than 2cm SL have been recorded (Johnson, 2004).

Reproduction

Nothing is known of the spawning mode (Leis, 2005). Only 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).

Behaviour

Like other velvetfishes, the Wasp-spine Velvetfish is likely to be bentho-pelagic in habit (i.e. free swimming near the bottom).

Fisheries Information

The species has been recorded in commercial trawl bycatch (Queensland Fisheries Service data, W.A. Department of Fisheries data, N.T. Fisheries data, cited in Johnson, 2004), but the frequency of occurrence is not known for this report, nor any information on population impacts.

Vulnerable Characteristics of the Species and Threatening Processes

The inshore distribution, benthic nature, and apparent rarity of this species in southern Australia may make populations susceptible to site-specific impacts in some areas. The species is found in various shallow subtidal habitats, and degradation of nearshore seagrass and soft-bottom habitat may be a threat to populations in some areas, but there are no specific data. In some tropical parts of the range (e.g. Thailand and Viet Nam), coastal developments and reclamation of mangrove habitats may be threat to local populations of this species, but there are no specific data.
Due to the occurrence of this benthic, site-associated species in nearshore, soft bottom habitats (including the gulfs region of S.A.), it may be vulnerable to capture in trawls. Very few data are available for any part of Australia, and there is insufficient knowledge of the extent to which trawl capture is a threatening process for Wasp-spine Velvetfish populations.
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 Acanthosphex leurynnis from Spencer Gulf and Gulf St Vincent in South Australia, and from Perth in W.A., should be examined and compared, if possible, with those from the tropical and sub-tropical parts of the range.
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 S.A., presence of this species in trawl bycatch should be recorded over space and time.
Surveys of shallow-water fish species in seagrass and rubble habitats should also consider the potential presence of small Velvetfish in such habitats.
Dredging and channel clearing programs need to be conscious of the potential presence of cryptic, benthic fish species such as Velvetfishes.

Other Information

The species appears to be uncommon, and is known mostly from tropical areas, although recent records from the South Australian gulfs are notable. It is possible that Acanthosphex leurynnis would be overlooked during most surveys in suitable habitats, due to its very small size and apparently cryptic appearance.