© 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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URANOSCOPIDAE: STARGAZERS

© MLSSA

The Uranoscopidae is a family of mostly marine-dwelling fishes, distributed in warm and temperate waters of the Atlantic, Indian, and Pacific oceans (Kishimoto, 2001; Froese and Pauly, 2007). Currently, there are about 52 named species in the family (Froese and Pauly, 2007), and at least 22 of these occur in Australian waters (CSIRO, 2007).
Members of the family Uranoscopidae are bottom-dwelling, and many bury in the substrate with just their eyes exposed, particularly during daylight. Stargazers have a large head encased in sculptured bones; a cavernous, vertical mouth; a large (often venomous) spine above the pectoral fin base, and most species have eyes that are directed upward (Gomon, in Gomon et al., 1994; Kuiter, 1996a; Kishimoto, 2001). Stargazers are “ambush predators” that lie almost buried in seafloor sediments, and wait for passing food, which is grabbed using the large, protrusible jaws, and consumed whole. In southern Australia, Stargazer species eat mainly bony fish, but cephalopods and benthic crustaceans also form part of the diet. Predators of stargazers include Australian and Fur Seal and New Zealand Fur Seal (e.g. Page et al., 2005).
Although Stargazers are benthic species, they have a pelagic juvenile stage. Most stargazer species settle back to the bottom at a very small size; however the deep-water species Pleuroscopus pseudodorsalis (Scaled Stargazer or Purple Stargazer) is pelagic at a larger size, and settles to a benthic existence when about 28cm long. During the pelagic phase, P. pseudodorsalis is a square-shaped fish, with spiked scales and horn-like head ridges, and eyes on the side of the head. In southern Australia, the pelagic stage has been caught hundreds of metres above the sea floor, by long-line fishing. Upon settling, Scaled Stargazers become flabby adult animals with embedded scales, no spikes, and eyes on the top of the head (Kishimoto et al., 1988, and research by Gomon and Last, cited by National Oceans Office, 2003).
Stargazer genera in southern Australia include Ichthyscopus, Kathetostoma, and Pleuroscopus. Within the genus Kathetostoma, the Common Stargazer is considered to have a broad distribution across southern Australia (pending further study of the species), whilst the Speckled or Western Stargazer K. canaster is found mainly in south-eastern Australia, and the Deepwater Stargazer K. nigrofasciatum occurs mainly in south-western Australia. South Australia represents the western and eastern edge of the respective distributions of K. canaster and K. nigrofasciatum.

Commercial Fishing

When taken outside of 3 nautical miles (NM) from the coast, catches of stargazers are managed by the Commonwealth. States manage catches taken inside 3 NM (AFMA, 2002a).
In south-eastern and southern Australia, species taken in fisheries bycatch include the variously named Scaled, Purple or Deep-sea Stargazer (Pleuroscopus pseudodorsalis); the Western or Speckled Stargazer Kathetostoma canaster (which are marketed as “monkfish”); the Bulldog Stargazer Gnathagnus innotabilis (caught in south-eastern Australia, with some retained and some discarded) and the smaller K. nigrofasciatum (Deepwater Stargazer) which is discarded (AFMA, 2002a; Brown and Knuckey, 2002; Wayte et al., 2004; C.H. Smith Marine, 2004).
In New Zealand, the Stargazer Kathetostoma giganteum is a commercial resource. During the past decade to 2004, the annual quota has ranged between 4,973t and 5,117t, and the catch ranged between 2,132t and 4,146t (New Zealand Ministry of Fisheries, 2005a). Concern has been expressed by a conservation organisation in New Zealand (Royal Forest and Bird Protection Society of New Zealand Inc.) that the fishery for K. giganteum is environmentally unsustainable, and this species has recently been listed in the “Red” category (i.e. to be avoided) in the Best Fish Guide, a consumer guide to environmentally responsible fish consumption. The main concerns expressed with regard to fishing K. giganteum were reported to be: “the unknown sustainability of some catch levels and limits; the habitat destruction caused by bottom trawling; the uncertainty over stock boundaries; the absence of quantitative stock assessments for any areas, and the lack of a management plan (Weeber and Szabo, 2004).
A number of species found in the continental shelf waters of South Australia are discussed below, due to their benthic existence, strong site association, possibly low resilience to exploitation, and potential vulnerability of populations to direct impacts (from fishing) or indirect impacts (e.g. benthic habitat damage).

Associated taxa

Fringed Stargazer / Fringe Stargazer	Ichthyscopus barbatus Mees, 1960
Deepwater Stargazer / Blackbanded Stargazer	Kathetostoma nigrofasciatum Waite and McCulloch, 1915
Speckled Stargazer / Western Stargazer	Kathetostoma canaster Gomon and Last, 1987
Common Stargazer / Eastern Stargazer	Kathetostoma laeve (Bloch and Schneider, 1801)