© 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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Noarlunga Hulafish / Yellow-headed Hulafish / Trachinops

Family Name:	Plesiopidae
Scientific Name:	Trachinops noarlungae Glover, 1974
Recommended Status in S.A:	Least Concern
Rationale:  Noarlunga Hulafish is included here because (i) the central coast of South Australia is at the edge of the geographic range; (ii) species of Trachinops appear to be territorial; they are strongly associated with  reefs and other structures in shallow nearshore waters, and they reproduce at localised scales, having benthic eggs that are guarded; these characteristics can make populations vulnerable to localised impacts; (iii) research on a related hulafish species in eastern Australia has shown that Trachinops species are susceptible to population impacts from nearshore pollutants, such as effluent discharge; (iv) the species is taken in W.A. for the aquarium trade, and fishes with such value may prompt illegal trade (or personal collecting) in other parts of southern Australia, where no specific fishery exists; (v) little information exists about the biology and population dynamics of this species. Despite the vulnerable population characteristics of T. noarlungae, the species is locally abundant in some parts of S.A., and currently, there is no existing evidence of decline. The recommended status at present is therefore Least Concern.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

The species has a south-western Australian distribution, from approximately the Houtman Abrolhos area in W.A., through to Kangaroo Island in S.A. (Hutchins and Swainston, 1986, 2001; Edgar, 2000).

South Australia

Noarlunga in Gulf St Vincent is the type locality (Glover, in Scott et al., 1974).
Examples of locations in S.A. where the species has been recorded include Nuyts Archipelago and the Investigator group islands, in the eastern Great Australian Bight; southern Eyre Peninsula (e.g. Perforated I.); south-western Spencer Gulf / Thorny Passage (e.g. McLaren Point); eastern Spencer Gulf (Port Hughes, Cape Elizabeth); metropolitan Gulf St Vincent (Grange tyre reef, Glenelg tyre reef, Hallett Cove reef, Port Noarlunga reef and Port Noarlunga tyre reef); south-eastern Gulf St Vincent / Fleurieu Peninsula (e.g. Aldinga, Rapid Head, Rapid Bay, Second Valley); south-western GSV (e.g. Edithburgh, Coobowie); northern Kangaroo Island (e.g. Snug Cove, Stokes Bay), north-eastern Kangaroo I. (Penneshaw), and Encounter Bay (Scott et al., 1974; Kuiter, 1983; Branden et al., 1986; K. Branden and S. Shepherd, unpubl. data, 1987; K. Branden, unpubl. data, 1988; Branden et al., 1994; Metters, 1999; S. Shepherd and J. Baker, unpubl. data, 2002-03; S. Shepherd, J. Brook and D. Ashcroft, unpubl. data, 2002; S. Shepherd and K. Brown, unpubl. data, 2002; Hutchins and Swainston, 1986, 2001; Shepherd and Brook, 2002b; S. Shepherd, unpubl. data, 2005; photograph by J. Lewis, undated; S.A. Museum data, cited in OZCAM database, 2006; Australian Museum, 2006f; Edgar et al., 2006).
Noarlunga Hulafish is locally abundant in some areas, with examples including islands in the Investigator Group (Kuiter, 1983); some islands off southern Eyre Peninsula (K. Branden and S Shepherd, unpubl. data, 1987); north-east Kangaroo Island, such as Kangaroo Point and other locations (Edgar et al., 2006); Glenelg tyre reef (K. Branden, unpubl. data, 1988); and parts of southern Gulf St Vincent, such as Port Noarlunga and Aldinga (S. Shepherd and J. Baker, unpubl. data, 2002-2003), Carrickalinga, Myponga, and Rapid Head (Edgar et al., 2006), Rapid Bay Jetty (S. Shepherd, unpubl. data, 2005), and Second Valley (Edgar et al., 2006).

Habitat

The species is found on sheltered and moderately exposed coastal reefs (Hutchins and Swainston, 1986, 2001; Edgar, 2000).
Noarlunga Hulafish is common on reefs and can form large schools near the entrance to caves (Edgar, 2000) and overhangs.
Noarlunga Hulafish is also common under jetties (Australian Museum, 2006f) and is associated with other artificial structures, such as tyre reefs (Branden et al., 1994) and breakwaters.
The recorded depth range is around 4m to 30m (Edgar, 2000).

Notes on the Biology and Behaviour

Growth

Noarlunga Hulafish grows to at least 10cm (Hutchins and Swainston, 1986, 2001), possibly 15cm (Kuiter, in Gomon et al., 1994; Kuiter, 1996a; Edgar, 2000).

Behaviour

The species often forms large schools (Hutchins and Swainston, 1986, 2001).

Reproduction

Members of Trachinops lay benthic eggs which have anchor-shaped hooks (Mooi, 1990).
The eggs of T. noarlungae are tightly bound together and deposited in a protected position (such as a rock crevice) on the substratum. For example, one diver in S.A. (J. Lewis) has photographed clusters of T. noarlungae eggs inside a Pinna “razorfish” shell.
Male Trachinops are responsible for guarding eggs. For example, the male of the eastern Australian species T. taeniatus has been observed wrapping its long body around the brood, to guard the eggs.

Diet

T. noarlungae is planktivorous (Kuiter, 1996a; Shepherd and Brook, 2002b).

Fisheries and Trade Information

Commercial

The species is taken in W.A. for the aquarium trade. In 2002-2003, 455 specimens of T. noarlungae were captured for sale to the aquarium industry. Between 1976 and 2003, around 3,591 specimens are recorded as having been taken for this industry (Department of Fisheries, Western Australia, 2004b). In 2005, T. noarlungae specimens for export were selling for US$6 per fish (Ryan and Clarke, 2005).

Vulnerable Characteristics of the Species

Hulafish reproduce at localised scales and have benthic eggs, a life history characteristic that increases their vulnerability to site-specific impacts.
Research on the related eastern Australian hulafish species T. taeniatus has shown that hulafish populations may be susceptible to the impacts of sewage effluent discharge. Various studies have reported lower abundance of hulafish (Smith and Suthers, 1999; Smith et al., 1999), smaller body size, and greater number of smaller eggs in hulafish at sewage-affected sites, compared with those in control areas (Smith and Suthers, 1999). Hulafish can take up sewage effluent into the muscle. Gaston et al. (2004) reported that the muscle of T. taeniatus hulafish from near some outfall sites was significantly enriched by secondary and tertiary treated effluent (compared with control sites), and estimated that 30-50% of the ¹⁵N nitrogen in the hulafish may be sewage-derived.

Threatening Processes

The main threats to this species may be habitat degradation in some inshore areas (see above, on effluent discharge); and (in some areas) collection for the aquarium trade.

Research Requirements

More information is required on the distribution and relative abundance of this species, particularly in central South Australia, which is at the edge of the species range.
Very little is known of the biology and population dynamics (especially longevity, and reproduction) and ecology of this species.

Management Requirements

Given that research in eastern Australia has shown that hulafish populations are susceptible to population impacts from effluent discharge, continuing efforts to reduce (and eventually eliminate) effluent discharges into nearshore waters should be made, particularly in the gulfs region of S.A., major parts of which are significantly affected by such pollutants.
Reef fish species taken in all southern States for the aquarium trade should be documented over space and time, and sustainability assessments should be undertaken. The potential for illegal collecting of this species should also be monitored and prevented.

Other Information

In W.A., Noarlunga Hulafish is sometimes called Yellow-headed Prettyfin.
Estimating abundance of hulafish is difficult, given the schooling nature of these species, and the high variability in abundance over space and time (e.g. Barrett et al., 2002).