© 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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Spiny Boxfish / Black-banded Pygmy Boxfish

Family Name:	Aracanidae (or Ostraciidae, sub-family Aracaninae)
Scientific Name:	Capropygia unistriata (Kaup, 1855)
Recommended Status in S.A:	Data Deficient
Rationale:  Included here because (i) the Spiny Boxfish apparently has a limited distribution in South Australia, and there are few recent records of this species in S.A., other than from trawl bycatch in the Great Australian Bight; (ii) generally, temperate boxfishes are strongly site-associated / territorial and haremic, characteristics that can increase the vulnerability of populations to localised impacts; (iii) C. unistriata is vulnerable to capture by trawlers in both State and Commonwealth waters (particularly in the GAB Trawl fishery), and trawl-caught specimens are unlikely to survive capture; and (iv) there is very little existing information about the biology, population dynamics, habitats or relative abundance of this species across its range.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

The species is known mostly from S.A. and W.A. (Hutchins and Swainston, 1986), but several specimens have been recorded from southern Victoria / Bass Strait (including one from 70m depth, 64 km SSW of Cape Schanck; 2 in the beachwash, at Glenaire and Apollo Bay, and several unverified CSIRO trawl records from 1967) (Kuiter, in Gomon et al., 1994; CSIRO Marine Research data, cited in CSIRO, 2007; Museum of Victoria records, cited in OZCAM database, 2007).
There are numerous records from the Great Australian Bight (GAB) (southern W.A. and western S.A.) (CSIRO Marine Research data, cited in CSIRO, 2007; Australian Museum records, Museum of Victoria records, cited in OZCAM database, 2007).

South Australia

Examples of location in S.A. where the species has been recorded (mostly in trawl catches) include waters throughout the GAB (from Anxious Bay area on the eastern side, through to the W.A. border); waters off the Kangaroo I. coast; deeper waters west and north-west of Kangaroo I., and south of lower Eyre Peninsula; deeper waters west of lower Eyre Peninsula, in south-eastern GAB; Wedge I. at the bottom of Spencer Gulf; the “heel” of Yorke Peninsula; southern Fleurieu Peninsula (e.g. Yankalilla area, collected in 1959 by T.D. Scott); and Victor Harbor / Encounter Bay area (Glover, 1979; Hutchins and Swainston, 1986; Brown and Knuckey, 2002; CSIRO Marine Research records, cited in CSIRO, 2007; Australian Museum records, SA Museum records, Museum of Victoria records, cited in OZCAM database, 2007). Most survey and museum records are trawl specimens from the Great Australian Bight (CMR warehouse records map, cited in CSIRO, 2007).
There are also old records (from 1909 and 1915) of specimens, reported to be this species, taken from central Gulf St Vincent and central Spencer Gulf (N.B. prior to the development of prawn trawling in these areas), and from deeper waters off the Coorong coast and Lacepede Bay, upper South East (South Australian Museum records, Australian Museum records, cited in OZCAM database, 2007).

Habitat

This species is found in deeper waters of the continental shelf (May and Maxwell, 1986, cited in Froese and Pauly, 2007; Kuiter, in Gomon et al., 1994). The reported depth range is 60m – 200m (May and Maxwell, 1986, cited in Froese and Pauly, 2007; Kuiter, in Gomon et al., 1994). There is little published information about the habitat of the Spiny Boxfish, which is mostly observed in trawl catches. It is noted that some of the museum records of this species from shallower regions (e.g. south-central Gulf St Vincent and Spencer Gulf), have been taken in waters shallower than the published depth range.
The species is occasionally seen washed up on beaches after heavy storms (Kuiter, in Gomon et al., 1994).

Notes on the Biology and Behaviour

Growth

This small species grows to around 10cm (Kuiter, in Gomon et al., 1994), 11cm (Hutchins and Swainston, 1986), or 12cm (May and Maxwell, 1986, cited in Froese and Pauly, 2007).

Diet

In general, boxfishes are benthic feeders (Kuiter, 1996a) that eat small sessile invertebrates, and algae (Nelson, 1994, cited in Froese and Pauly, 2007).

Reproduction

According to Kuiter (2000), temperate boxfishes are protogynous hermaphrodites, and when in captivity, females of some species in the Aracanidae have been observed transforming into males.

Other Information

Diagnostic features of the species include the black lips; black bases on the dorsal and anal fins, and black rings around the spines on the body (Hutchins and Swainston, 1986).

Fisheries Information

The Spiny Boxfish is known almost exclusively from trawl bycatch (May and Maxwell, 1986; Kuiter, in Gomon et al., 1994; CSIRO Marine Research records, cited in CSIRO, 2007; Australian Museum records, SA Museum records, Museum of Victoria records, cited in OZCAM database, 2007).
Spiny Boxfish form a part of the bycatch in the Commonwealth-managed Southern and Eastern Scalefish and Shark Fisheries (SESSF) (AFMA, 2002a). In the Danish seine sub-fishery of the South East Trawl Fishery, an Integrated Scientific Monitoring Program (ISMP) recorded Spiny Boxfish C. unistriata as a minor bycatch species (i.e. 1kg per shot, and recorded in only 2 shots during the program). It is not known for this report whether the results from the ISMP program were representative of the annual catch of this species in the SETF.
In the GAB Trawl Fishery, bycatch sampling in 2000 and 2001 (Brown and Knuckey, 2002) showed that Spiny Boxfish were caught and discarded. During the sampling period, Capropygia unistriata was observed in 44 of the 209 trawl shots; the average quantity discarded was 1kg per trawl shot (Brown and Knuckey, 2002).
Reportedly, the species has been recorded from the prawn trawl catch off lower Yorke Peninsula / Investigator Strait (South Australian Museum record, cited in OZCAM database, 2004).

Vulnerable Characteristics of the Species

Spiny Boxfish apparently has a limited presence in S.A., known mainly from the Great Australian Bight. The few reports of this species from other parts of S.A. are older museum records (mostly early 1900s), and the species may be uncommon in most parts of South Australia.
In general, boxfishes are site-associated, territorial, haremic species, characteristics that can increase their vulnerability to site-specific impacts.

Threatening Processes

Trawling may be a threatening process. There is no knowledge of population sizes, and the species is discarded from trawl bycatch. Given that boxfishes from continental shelf waters suffer barotrauma when hauled up (e.g. N.S.W. Department of Primary Industries, 2004), survival is likely to be low for trawl-caught and discarded specimens.

Research and Management Requirements

More information is required on the distribution (particularly in South Australia) and abundance of this species, given that museum specimens (verified by R. Foster and R. Browne, pers. comm., 2006) have been recorded in relatively shallow waters, such as central GSV and Spencer Gulf in South Australia. Also not well known is the habitat of the Spiny Boxfish in deeper, Commonwealth-managed waters, from which most specimens have been recorded, in trawl catches.
Trawl fisheries in S.A. State waters (e.g. prawns) and Commonwealth waters (fish trawls) should monitor the presence of this species in the bycatch, over space and time. Assessments of the vulnerability of Spiny Boxfish populations should be undertaken, particularly in fisheries such as the GAB Trawl Fishery, in which the species is regularly caught and discarded. Pending the results of population assessments, methods may need to be devised to limit the bycatch of this species.
The life history is not well known, and information on the habitat, habits, biology and population dynamics of Spiny Boxfish may also assist in managing potential impacts on this species, such as bycatch in trawlers.