© 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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Butterfly Gurnard

Family Name:	Triglidae
Scientific Name:	Lepidotrigla vanessa (Richardson, 1839)
Recommended Status in S.A:	Data Deficient
Rationale:  Although it has a broad distribution across southern Australia, L. vanessa is included here because (i) it is a site-associated benthic species from upper- and mid-continental shelf waters, in sand and mud habitats, and thus may be vulnerable to site-specific impacts in some areas (ii); it is vulnerable to capture in a number of fisheries across the range, including fish trawls, prawn trawls, fish and shark gillnets and long-lines, and scallop dredges (and in Tasmania, it is also taken for the aquarium industry) (iii) risk assessments in trawl fisheries indicate that the species has a low resilience, and low probability of survival when caught in trawls, and populations are considered to be at medium to high risk of impact, in various fisheries across the range; (v) in South Australia, there is inadequate information about the bycatch of this species; and (vi) data on relative abundance over the range are inadequate, and there is little information on the biology (including longevity, reproduction, recruitment strength etc), population dynamics and ecology of this species.

Page Contents

Current Conservation Status

no listings known

Distribution

Southern Australia

A fairly common species, distributed from New South Wales through to Tasmania and across southern Australia to the Great Australian Bight, southern W.A. (Gomon, in Gomon et al., 1994). There are many museum specimen records from Victoria and Bass Strait (Museum of Victoria records, cited in OZCAM database, 2007).

South Australia

Examples of locations in S.A where the species has been recorded include the head of the Great Australian Bight (GAB) and eastern GAB; southern Eyre Peninsula (e.g. Spalding Cove); southern Yorke Peninsula / south-western Gulf St Vincent (Edithburgh Jetty), metropolitan Gulf St Vincent (e.g. Outer Harbour, and Brighton, the latter an unverified record) and Fleurieu Peninsula (e.g. Rapid Bay) (Reynolds, 1997; K. Smith, unpubl. data, 2004; Australian Anglers Association, 2005; South Australian Museum records, Museum of Victoria records, cited in OZCAM database, 2007; CSIRO data, cited in CSIRO, 2007).
Most of the published records of this species are from trawl surveys undertaken during the 1970s and early 1980s in continental shelf waters of the central and eastern Great Australian Bight (CSIRO Marine Research data, cited in CSIRO, 2007).

Habitat

L. vanessa occurs in sand and silt habitats in coastal waters, with the reported depth range of 10m – 100m (Edgar, 2000). The species is found mostly found in waters greater than 20m (Edgar, 2000).
Juveniles occasionally enter estuaries (Edgar, 2000).

Notes on the Biology

Growth

L. vanessa grows to around 28cm (Gomon, in Gomon et al., 1994)

Diet

Early observations (during the 1880s) of the diet included “small shells and crustacea” (McCoy, undated). Small fish have also been recorded as part of the diet of L. vanessa (Bulman et al., 2001).

Reproduction

Lepidotrigla species have buoyant, pelagic eggs (Neira et al., 1998).

Other Information

Like other gurnards, this species can “walk” along the sea floor using the feelers in front of the enlarged pectoral fins (Hutchins and Swainston, 1986).

Fisheries Information

Commercial - Commonwealth Fisheries

When taken outside of 3 nautical miles (NM) from the coast, catches of L. vanessa are managed by the Commonwealth (and when taken inside 3 NM, are managed by the States) (AFMA, 2002a).
Butterfly Gurnard is the largest species of the Lepidotrigla genus in southern Australian waters, and is often taken by commercial trawlers, especially in the Bass Strait region (Gomon, in Gomon et al., 1994). The marketing name is “Butterfly Gurnard” (Seafood Services Australia, 2003). Butterfly Gurnard is part of the bycatch in the Commonwealth-managed Southern and Eastern Scalefish and Shark Fisheries (SESSF) (AFMA, 2002a). In the otter trawl sub-fishery of the South East Trawl Fishery (SETF), an Integrated Scientific Monitoring Program during the early 2000s reported that 67kg of L. vanessa was retained in 18 trawl shots (average 3.7kg per trawl shot) and 7kg were discarded (Wayte et al., 2004). In the Danish seine sub-fishery of the SETF, the ISMP reported that in 24 shots, about 95kg of this species were retained (nearly 4kg per shot), and 3kg discarded (Wayte et al., 2004).
Butterfly Gurnard is also reported to be a retained by-product species in the Gillnet, Hook and Trap (GHAT) fishery (Bromhead and Bolton, 2005). For Commonwealth licence holders with Scalefish Hook, Shark Hook, Gillnet Sectors and Coastal Waters permits, Butterfly Gurnard may be caught in Commonwealth waters (outside 3NM) but not in coastal waters (inside 3NM), with a concession that allows methods other than trawl, and there are no catch restrictions (AFMA, 2004e). There are few data available, but it is noted that during a bycatch study in the Southern Shark Fishery in south-eastern Australia between 1973 and 1976, L. vanessa was vulnerable to capture in 3-inch and 4-inch gills nets, in which 69 (SE = 37) specimens and 41 (SE = 24) specimens respectively were caught per 1000 km-hours (Walker et al., 2003). It is noted that mesh nets of these small sizes are no longer used in the fishery. During another bycatch experiment in 1973-76, a total of 36 (SE = 27) specimens per 1000 km-hours were caught using 4/O shark hooks (Walker et al., 2003). In the formerly named South East Non-Trawl Fishery, Knuckey et al. (2001) recorded L. vanessa as a very minor component of the long-line catch in south-eastern Australia.
Butterfly Gurnard is also retained when caught in the Great Australian Bight Trawl Fishery (GABTF) (Bromhead and Bolton, 2005). In the GABTF, a monitoring program in 2001-02 recorded the species in 14 (out of 209) trawl shots, and 2.3 kg per trawl shot were retained, with negligible quantities discarded (Brown and Knuckey, 2002).
Butterfly Gurnard is part of the retained by-product in the Tasmanian section of the Small Pelagic Fishery (AFMA, 2002a, 2003h; Bromhead and Bolton, 2005). In a bycatch recording program during the early 2000s, several individuals were observed in a few shots, with up to 30 kilograms in isolated shots (AFMA, 2003h).

Commercial – State Fisheries

Butterfly Gurnard is a minor part of the discarded bycatch in the Bass Strait Scallop Fishery. For example 1 specimen of L. vanessa was recorded in 35 random tows, during a bycatch survey in 2001 and 25 specimens were recorded in 59 random tows, in 2002 (Haddon and Semmens, 2001, 2002), and 4 were recorded in 17 tows in 2003 (Haddon and Semmens, 2003).
In New South Wales, L. vanessa is a significant part of the bycatch in the Wreck Bay and Tathra inshore grounds of the ocean fish trawl fishery, with a frequency of occurrence of 51% across all trawls (N.S.W. Department of Primary Industries, 2004).
L. vanessa is collected in Tasmania for the aquarium industry. The permitted annual catch limit is 300 individuals, with a fishing block limit (6 x 6 nautical miles) of 50 individuals (DPIWE Tasmania, 2005b; Australian Government DEH, 2005b). The species is available as a cool water aquarium fish from a supplier in New South Wales.

Recreational

Some recreational fishers in southern Australian states (including South Australia) catch gurnards, including the Butterfly Gurnard. Statistics on the capture of gurnards by recreational fishers in 2000-01 were provided by Henry and Lyle (2003), and are cited above; however, species-specific information is not available.

Vulnerable Characteristics of the Species, and Threatening Processes

This site-associated benthic species from sand and silt habitats in upper and mid continental shelf is vulnerable to capture by a variety of gear (e.g. fish and prawn trawl nets, seine nets, gill nets, shark hooks, long-lines, scallop dredges).
Site-associated benthic fish species such as gurnards may be susceptible to localised impacts in some areas where benthic habitats are degraded, but there are no data.
L. vanessa has been listed as one of the bycatch species in the N.S.W. Ocean Trawl Fishery that has a “high” fishery impact profile (N.S.W. DPI, 2004). Studies in New South Wales showed that the species suffers barotrauma when hauled in trawls; has “low to moderate resilience”, and a low probability of survival when caught, and L. vanessa was classified overall as a “high risk” species in terms of population impacts from trawl fishing (N.S.W. DPI, 2004).
In a draft ecological risk assessment of the SETF (Wayte et al., 2004), four “productivity attributes” and five “attributes of susceptibility” for L. vanessa were used to categorise it as a “medium risk” species in terms of susceptibility to population impacts from trawling in that fishery.

Research Requirements

There is little information on distribution and relative abundance over the range, and on the biology (including longevity, reproduction, and recruitment strength), population dynamics and ecology.
There is inadequate information about the bycatch of this species in South Australian fisheries. In S.A., the presence of this species in the prawn trawl fisheries in West Coast, Spencer Gulf and Gulf St Vincent should be ascertained, because it occurs in the areas trawled by those fisheries, but bycatch data are not usually recorded in two of those three fisheries. In all fisheries where this species is taken in more than incidental quantities, bycatch should be reported and monitored.
More generally, bycatch of gurnard species in all coastal fisheries should be recorded at species level, over space and time. Ideally, long term monitoring of the quantities of gurnard species in the bycatch of trawl fisheries should be undertaken before and after the adoption of gear improvements to reduce bycatch, and in “control” (non-trawled) areas.

Management Requirements

In south-eastern and southern Australia, methods are required to reduce the bycatch of this species in fish trawl and prawn trawl fisheries (and to a lesser extent, in seine nets, gill nets, long-lines, scallop dredges and other gear) over the continental shelf, in both State and Commonwealth waters.
Although measures have already been undertaken in S.A. prawn trawl fisheries to reduce the bycatch of benthic fish species (see Management Notes, in synopsis on L. papilio), further improvements (e.g. in net design) should be encouraged, to reduce the bycatch of site-associated benthic species such as Butterfly Gurnard.
Recreational catch limits should be introduced for gurnard species.
In Tasmania, catches of L. papilio for the aquarium industry should be monitored, and sustainability over space and time should be determined.

Other Information

The species has been recorded in a number of protected areas in Victoria, such as Point Hicks Marine Park (Plummer et al., 2003).