© 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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Common Stargazer / Eastern Stargazer

Family Name:	Uranoscopidae
Scientific Name:	Kathetostoma laeve (Bloch and Schneider, 1801)
Recommended Status in S.A:	Data Deficient
Rationale:  Although the Common Stargazer may have a broad geographic range, it is included here because the species (i) is a benthic, site-associated fish in sand habitats of the upper continental shelf; it may be susceptible to localised impacts, and may have a relatively low resilience to exploitation; (ii) is a retained by-product in some Commonwealth fisheries; is a discarded bycatch in a variety of State-based fisheries, and is caught occasionally by recreational fishers, with no Commonwealth- or State-level controls over capture in any fishery; (iii) there are inadequate data on the relative abundance (including the S.A. part of the range), biology (particularly reproduction and longevity), and population dynamics; and (iv) there are insufficient data on the commercial catch (retained by-product and discarded by-catch) and recreational take over space and time, and inadequate assessment of the potential population impacts of fishing.

Page Contents

Current Conservation Status

No listings known

Distribution

Southern Australia

The Common Stargazer is reportedly found across southern Australia, from mid-northern N.S.W., through to southern W.A., and Tasmania is part of the distribution (Hutchins and Swainston, 1986; Gomon, in Gomon et al., 1994; Edgar, 1991, 2000).
The specimens from western South Australia and south-western Australia may represent a distinct species (Gomon, in Gomon et al., 1994; Kuiter, 2000; Australian Museum, 2004k). Populations from south-eastern and south-western Australia are distinct at least at sub-species level, and although the taxonomic status is still uncertain, they are likely to be separate species (M. Gomon, Museum of Victoria, pers. comm., 2006).

South Australia

In South Australia, the species has a broad distribution, and has been regularly observed in the two gulfs. Examples of locations where Common Stargazer has been recorded include the eastern, central and western Great Australian Bight (CSIRO Marine Research trawl survey records, reported to be this species, from deeper continental shelf waters); Ceduna area; Nuyts Archipelago area; northern Anxious Bay / Venus Bay area off western Eyre Peninsula; Elliston / Waterloo Bay area; south-western Eyre Peninsula / Coffin Bay area; parts of Spencer Gulf (e.g. Port Broughton, Tiparra, Moonta Bay, Port Hughes, Tumby Bay, Point Bolingbroke); parts of southern Yorke Peninsula (e.g. Stenhouse Bay, Sturt Bay area, Troubridge Island, Edithburgh); western Gulf St Vincent (e.g. Port Giles); metropolitan Gulf St Vincent (e.g. Brighton area, Glenelg area, including Glenelg Dredge); southern Fleurieu (e.g. Yankalilla Bay, Carrickalinga area, Parsons / Waitpinga area); mouth of Gulf St Vincent / eastern Investigator Strait; and the north-eastern Kangaroo Island bays region (records from divers and diving clubs in S.A., cited by Baker, 2004; CSIRO Marine Research data 1979, cited in CSIRO, 2005; J. Brook, Reef Watch, pers. comm., 2002; Fairhead et al., 2002a; photograph by F. Bavendam, undated; photographs by J. Lewis, May and September, 2004; K. Smith, pers. comm., 2005; S.A. Museum records, Museum of Victoria record, cited in OZCAM database, 2007).

Habitat

The Common Stargazer is a benthic species found in sandy habitats in shallow water, between 0m and about 60m deep (Gomon et al., 1994; Edgar, 2000). It is noted there are records, reported to be this species, from deeper waters (e.g. CSIRO Marine Research trawl survey data, 1979, cited in CSIRO, 2007); however deeper water records from the GAB may represent a separate species.
The Common Stargazer occurs in shallow, sheltered to moderately exposed bays, estuaries and other quiet coastal waters, and other nearshore habitats, with sandy, silty or shelly bottoms (Gomon et al., 1994; Edgar, 2000; Museum of Victoria, 2005a).
In eastern Victoria, the Common Stargazer has been reported from sandy plains near reefs (DSE Victoria, 2002), Heterozostera tasmanica seagrass beds (Hindell et al., 2000), and also from under jetties (Evatt, 2003). Similarly in S.A., the species has been recorded buried in sand, adjacent to reef patches (J. Brook, unpubl. data, 2002), and jetties. In Tasmania, Common Stargazer has been recorded in estuaries (e.g. Edgar et al., 1999), and from reef and sand habitats in various coastal bays and channels (Lyle at al., 2000), the latter including very shallow waters off beaches (e.g. Jordan et al., 1998).

Notes on Biology and Behaviour

Growth

The Common Stargazer grows to about 75cm (Gomon, in Gomon et al., 1994; Edgar, 2000).
The species grows to at least 5.6kg. For example, the Australian Underwater Federation reported that the record size of K. laeve taken by spearfishing was 5.67kg, being a specimen taken in 1964, at Woolami Beach in Victoria (Australian Underwater Federation, Inc., 2003). The national angling record is 4.933kg, being a specimen taken in N.S.W. in 1972 (Australian Anglers Association, 2005). The Victorian angling record is a specimen of 4.19kg (Australian Anglers Association (AAA), Victorian Division, 2003).
There is no information on the age of the species, but is it noted that a related species in New Zealand, K. giganteum, which grows to a similar size, reportedly reaches a maximum age of about 23 years (Sutton, 1999, 2004; Manning and Sutton, 2004).

Diet and Feeding Behaviour

A study of juvenile Common Stargazers in Victoria showed that the diet comprises mainly bony fish (80%, in the sample), with a lesser percentage of benthic crustaceans (Hindell et al., 2000). Stargazers lie almost buried and motionless, with the eyes and mouth protruding from the sand. The Common Stargazer can rapidly lunge upward, using its large, cavernous mouth to consume prey in one gulp.

Other Information

Stargazers in southern Australia form a small part of the diet of New Zealand Fur Seal and Australian Fur Seal (Page et al., 2005).

Fisheries Information

Commercial – Commonwealth

The Common Stargazer is part of the bycatch of fisheries such as the Commonwealth-managed SESSF (Southern and Eastern Scalefish and Shark Fisheries), which includes the South East Trawl Fishery (SETF) (AFMA, 2002a). In the SETF, Stargazer bycatch is not recorded to species’ level in fishers’ logbooks; however large quantities of unspecified stargazer species are recorded as bycatch. It is likely that the Common Stargazer does not form a substantial proportion of that catch, due to the shallow depths at which it occurs. A scientific monitoring program in 2001 recorded 671kg of Common Stargazer in the bycatch of the SETF, about 82% of which was retained (AFMA, 2002a). In the otter trawl sub-fishery of the South East Trawl Fishery, an Integrated Scientific Monitoring Program (ISMP) reported that in 452 trawl shots, about 1.86t of K. laeve was retained and 557kg discarded (Wayte et al., 2004), which is an average of 4kg per trawl shot retained, and 1.2kg per trawl shot discarded. The ISMP also recorded 4kg in a single shot in the Danish seine sub-fishery of the SETF, but the species was reported only in one shot (compared with 452, in the otter trawl sub-fishery sampling) (Wayte et al., 2004).
Bromhead and Bolton (2005) reported that K. laeve is a retained byproduct species in the Commonwealth-managed Gillnet, Hook and Trap fishery.

Commercial – Tasmania

The species is vulnerable to by-capture in large mesh gillnets, as used in finfish fisheries in Tasmania (e.g. Murphy and Lyle, 1999).
Kathetostoma laeve is a minor (and discarded) part of the bycatch in the Bass Strait Scallop Fishery (Haddon and Semmens, 2001, 2002; Bromhead and Bolton, 2005).
According to BRS (2004), commercial catch figures from Tasmania include the following: 15t in 1990/91, and 1t - 4t per annum between 1991/92 – 1994/94. No specimens were recorded between 1994/95 and 1998/99, and no data are available for the early 2000s.
K. laeve is sold in the aquarium market, and collected in Tasmania for that purpose. The permitted total annual catch limit is 60 individuals, with a fishing block limit (6 x 6 nautical miles) of 10 individuals (DPIWE Tasmania, 2005b; Australian Government DEH, 2005b).

Commercial – South Australia

In South Australia, the species has been recorded as a minor component of bycatch in the Spencer Gulf prawn trawl fishery. For example, 7 Common Stargazer were recorded from 32 trawl tows, in a sampling program during the mid 1990s (Carrick, 1997). It is noted that the species was also recorded in a trawl survey in the snapper grounds of upper Spencer Gulf (P. Jennings, SARDI, unpublished survey data, 2003).

Commercial – New South Wales

Stargazers form a small part of the bycatch in the Estuary General Fishery in New South Wales (New South Wales Fisheries, 2001).

Recreational

Common Stargazers are occasionally taken by hook and line (Museum of Victoria, 2005).
Common Stargazers are part of the recreational gillnet bycatch in Tasmania. Experiments have shown that the survival rate is high for specimens caught in gillnets in the recreational fishery (Lyle et al., 2000).
There are records of the species being taken accidentally by recreational line fishers in South Australia (e.g. SA Museum record F 04533, cited in OZCAM database, 2004).
There are records of the species being taken by spearfishing (e.g. Australian Underwater Federation, Inc., 2003). Common Stargazer is also caught irregularly (sometimes accidentally) by recreational fishers. For example, Wilson (2003) reported a ~4kg specimen taken by squid jig at a beach near Geelong. Some clubs and associations keep records of the maximum sizes of specimens caught by anglers (e.g. AAA, Victorian Division, 2003; AAA, 2005).
Species-specific data on the recreational catch of stargazers is not available for this report; however it is noted that the recent National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) reported that 1,782 Stargazer specimens were caught and kept by recreational fishers during the survey time period (May 2000 - April 2001), comprising 932 from Queensland, and 850 from N.S.W.. The number discarded was not recorded, nor were statistics from the southern Australian states.

Vulnerable Characteristics of the Species

Common Stargazer is a member of the Uranoscopidae, a family of strongly site-associated, benthic fishes of limited mobility, and probably limited dispersal ability. The strong site association of these fish makes them vulnerable to site-specific benthic impacts, such as trawling and dredging.
Common Stargazer has a relatively narrow depth range, known to date from the shallow subtidal to about 60m deep.
The species may have a low resilience to exploitation, in terms of minimum population doubling time (based on preliminary age and growth estimates) (Froese and Pauly, 2007).

Threatening Processes

Due to the benthic association and limited mobility of this species, localised benthic impacts, such as trawling, dredging and sand removal, may adversely affect populations of shallow-water Stargazer species, but there are no specific data.
In some areas, the combined effects of fishing by different methods (e.g. a combination of trawls, scallop dredges, gill-nets, hooks-and-lines, hand collecting, and/or spears) are likely to threaten some populations, but more information is required. It is noted that a draft ecological risk assessment of the South East Trawl and Danish Seine Fishery (Wayte et al., 2004), listed Common Stargazer as a “medium risk” species in that fishery, i.e. one of the species that is susceptible to population impacts from trawling.

Research and Management Requirements

The species identity of specimens from eastern and western Australia needs to be ascertained, and if two species are present, then the ranges of each (and the degree of overlap) need to be defined.
There is little information on the biology (particularly the reproduction and longevity) or population dynamics of this species.
No population or fisheries assessments have been undertaken, even in those fisheries in which Common Stargazer is a retained by-product. No data are available about the change over time in the abundance of this species in the bycatch of any fishery, nor are there any other indirect (or direct) measures of potential impact on populations. In particular, more information is required on the bycatch in commercial fish and prawn trawl fisheries (both Commonwealth- and State-managed), and gill-net fisheries (e.g. in Tasmania).
Quantification of Stargazer bycatch (to species’ level) in fisheries over space and time is recommended, and measures to reduce the bycatch of benthic species such as Stargazers are required, where possible.
In Tasmania, an assessment is required of the sustainability and/or potential population impacts of the commercial take for the aquarium industry.
Species specific recreational catch statistics are lacking, and stargazer species are generally not targeted by recreational fishers. Nevertheless, given the potential for populations of Uranoscopid fishes to be affected by fishing, catch limits are required for recreational fishing of shallow water stargazer species.

Other Notes

Common Stargazer is the only stargazer species in south-eastern Australia that is regularly seen by divers, although it is considered to be uncommon (Edgar, 2000). Night divers have been bitten by this species (Australian Museum, 2003k).
The Common Stargazer occurs in a number of the marine national parks and sanctuaries in Victoria, such as Popes Eye, Port Phillip Heads, and Ninety Mile Beach (DSE Victoria, 2002; Plummer et al., 2003).

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