© 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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ARACANIDAE: TEMPERATE BOXFISHES

Photo: © John Lewis

Fishes in the Aracanidae are closely related to the Boxfishes (Ostraciidae) and were previously considered to be a sub-family (Aracaninae). Boxfishes are distributed throughout the Atlantic, Indian and Pacific Oceans (Nelson, 1994, cited in Froese and Pauly, 2007). Some authors separate the temperate boxfishes and cowfishes into their own family, the Aracanidae, based on the structure of the carapace, position of the dorsal and anal fins, nature of the mouth, position of the eyes, and other features (see Fraser-Brunner, 1941; Kuiter, in Gomon et al., 1994; Kuiter, 1996a). The group has an Indo-Pacific distribution. There are around 6 genera and 13 species in the Aracanidae (Tyler, 1980, cited in Froese and Pauly, 2007), and most of the species are found in Australian waters (Kuiter, 1996a). More than half of the species in Aracanidae occur along the southern Australian coast (Kuiter, in Gomon et al., 1994). Following the separation of the Aracanid fishes, there are currently 6 genera remaining and 25 named species in the Ostraciidae family (Froese and Pauly, 2007).
The boxfishes are characterised by a bony carapace enclosing body; the absence of a pelvic skeleton, and a non-protrusible upper jaw, amongst other features. Many boxfishes live in deep water, but a number of species also occur in shallow coastal waters. Other common names in use for members of the family include cowfishes, trunkfishes and turretfishes. The largest boxfish in the world grows to around 60cm (Nelson, 1994, cited in Froese and Pauly, 2007); however most species, particularly the temperate ones, are smaller (e.g. 20cm – 30cm maximum length). Boxfishes feed on small sessile invertebrates and on algae. They are territorial and haremic, and reported to spawn eggs at dusk (Nelson, 1994, cited in Froese and Pauly, 2007). However, apparent mouth-brooding has been observed in cowfish (Aracana) near jetty remains at Wallaroo in South Australia (A. Brown, unpublished data, 1983). A number of species are poisonous, and members of the Ostraciidae and Aracanidae are not commonly fished, other than being discarded from trawl bycatch, or targeted by dive fishers for the aquarium industry. Many boxfishes are popular in the aquarium trade, due to their bright colouration and unusual shapes. There is an active market in the exporting and importing of these species. Boxfishes can extrude a poison (ostracitoxin) from the mouth when under stress, hence need to be kept separate from other aquarium fishes during such times (B. Hutchins, W.A. Museum, pers. comm., 2007).
Members of the Aracanidae are characterised by an external bony carapace that comprises rows of triangular plates, which form large hexagonal and square patterns over the side of the body (Kuiter, 1996a). The moveable parts (eyes, mouth, gills and pectoral fins) protrude through holes in the rigid body (Kuiter, in Gomon et al., 1994). Some species have horn-like spines on the head and dorsal body, resulting in the popular name “cowfish”. The temperate boxfishes and cowfishes are sexually dimorphic, with males in some cases being more brightly coloured, or having different patterns and body colours, compared with the females and juveniles. Like the tropical boxfishes, the temperate counterparts are benthic feeders, and species that occur in shallow waters are often seen near the bottom, blowing the sand away to expose prey (Kuiter, 1996a).
Two relatively common and widely distributed species in southern Australian are the sexually dimorphic species Shaw’s Cowfish Aracana aurita, and Ornate Cowfish Aracana ornata, found in both reef and seagrass habitats. The cowfishes are not discussed here as species of conservation concern due to their relative abundance and broad geographic distribution; however they the share vulnerable population characteristics of other members in the family (see below), and it is noted that the Aracana species are sometimes taken by fishers. For example, the National Recreational and Indigenous Fishing Survey (Henry and Lyle, 2003) reported that 111 Cowfish were caught and kept by recreational fishers in South Australia during the survey time period (May 2000 to April 2001). Cowfish are also vulnerable to capture in trawl and dredge fisheries. For example, Haddon and Semmens (2002) reported 60 Shaw’s Cowfish in the bycatch of 59 scallop tow shots, during a survey of the Bass Strait Scallop Fishery. In South Australia, observers have reported Cowfish as part of the bycatch in the Gulf St Vincent prawn fishery (Richardson, 1999). In S.A., during bycatch sampling in the Blue Crab fishery (2002-2003), no individuals were caught in 2003; however 3 Shaw’s Cowfish were caught in pots in Spencer Gulf in 2002 (= reported frequency of capture of 0.22%) (Svane and Hooper, 2004).  Cowfish are also popular in the aquarium trade, and a number of aquarium supply companies sell Aracana species in shops, and over the internet. A. aurita 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)[1]. In the commercial fishery in W.A. that serves the aquarium trade, it is reported that 1,467 Shaw’s Cowfish have been collected in W.A. waters since 1976, and the average annual catch between 2000 and 2003 was 146 individuals (W.A. Department of Fisheries, 2004b).
A number of temperate boxfish species are taken in trawl fisheries in southeastern Australia, southwestern Australia, and in the Great Australian Bight, sometimes in large numbers (e.g. see Brown and Knuckey, 2002; McAuley and Simpfendorfer, 2003; Wayte et al., 2004; New South Wales Department of Primary Industries, 2004). In the otter trawl sub-fishery of the South East Trawl Fishery, an Integrated Scientific Monitoring Program (ISMP) reported that in 257 trawl shots, about 5.17t of Anoplocapros inermis were discarded (Wayte et al., 2004). In New South Wales, Gray and Kennelly (2001) estimated that 6,106 (SE = 2,837) specimens of A. inermis were discarded in the estuary haul fishery in Botany Bay between February 1998 and January 1999. Fishery-independent surveys to assess bycatch composition in the N.S.W. Ocean Trawl Fishery have been undertaken, using ocean fish trawl and prawn trawl gear. Results showed that the percentage frequency of occurrence of the Eastern Smooth Boxfish Anoplocapros inermis across all trawls, was around 87% in the Wreck Bay and Tathra inshore grounds of the “ocean fish trawl shelf sector”; 24% in the entire “ocean fish trawl shelf sector”, and 67% in the “ocean prawn trawl shelf sector” (New South Wales Department of Primary Industries, 2004).
Four species are discussed in synopses below, due to their limited presence in South Australia, these being the White-barred Boxfish Anoplocapros lenticularis; the Western Smooth Boxfish A. amygdaloides; Rigid Boxfish Caprichthys gymnura, and Spiny Boxfish, Capropygia unistriata.

Associated taxa

White-barred Boxfish / Humpty Dumpty	Anoplocapros lenticularis (Richardson, 1841)
Western Smooth Boxfish / Blue Boxfish / Robust Boxfish	Anoplocapros amygdaloides Fraser-Brunner, 1941 A. robustus (Fraser-Brunner, 1941)
Spiny Boxfish / Black-banded Pygmy Boxfish	Capropygia unistriata (Kaup, 1855)
Rigid Boxfish	Caprichthys gymnura McCulloch and Waite, 1915