CRUSTacean research, no. 40: 1 – 11, 2011 1 Taxonomy, distribution and ecology of the Setose Yabby, Cherax setosus (Riek, 1951) Robert B. McCormack and Jason Coughran Abstract.– Although it occurs near al., 1998, 2002a). Most recently, however, and one of Australia’s largest cities, there using modern genetic techniques, Austin et is a remarkable lack of information on al. (2003) and Munasinghe et al. (2004) have the Setose Yabby, Cherax setosus. The confirmed that full specific rank is warranted. morphology of the species has never Although C. setosus is known from a few been thoroughly described, and basic sites near Newcastle (New South Wales), one information on its distribution and ecology of Australia’s largest cities, little is known is required. In this paper, we give a about the species. Lawrence et al. (2002b) thorough redescription of the species and described the habitat at one site where the present data on its distribution, habitat species was collected for laboratory studies, and general biology. Cherax setosus is a but after subsequent highway construction medium-sized crayfish with a lowland, that site no longer exists (Lawrence et al., coastal distribution extending from just 2002b). The laboratory studies did, however, south of Taree to just north of Morisset identify a potentially important role for C. in eastern New South Wales, a northeast- setosus in the aquaculture industry. Although southwest distance of approximately not commonly farmed itself, the species can 150km. The species is rarely found in be crossed with the Victorian ‘albidus’ strain permanent aquatic habitats in the area, of Cherax destructor to produce sterile, all- but builds extensive burrow networks in male hybrid offspring with increased vigor minor, ephemeral habitats such as gullies, (Lawrence et al., 1998, 2000). roadside ditches, stump holes, swamps Despite this aquaculture interest, C. and pastures. Although it appears to be setosus has remained poorly understood relatively common across its range, the and, consequently, there are no specific species may be susceptible to impacts management measures in place at present. such as reproductive interference with the A detailed description of the species is still translocated crayfish C. destructor and lacking, and virtually nothing has been predation on juveniles by the introduced published on its biology or ecology. These plague minnow, Gambusia holbrooki. research gaps on C. setosus are clearly inadequate given its apparent restriction to a rapidly developing area. Another current Introduction concern is that the translocated yabby species Cherax setosus (Riek, 1951) (Fig. 1) was C. destructor is becoming widely established originally described by Riek (1951) as a across eastern New South Wales (Coughran subspecies of Cherax rotundus Clark, 1941, et al., 2009) and may threaten the endemic and was later reclassified by Austin (1986) as aquatic fauna, including the endemic yabby C. a subspecies of C. destructor Clark, 1936. The setosus. It is therefore imperative that these taxonomic position of the species has also fundamental research gaps on C. setosus are been discussed by various other authors (Riek, addressed. 1969; Sokol, 1988; Austin, 1996; Lawrence et To facilitate future research and 22 R. B. MCCORMACK & J. COUGHRAN Fig. 1. The Setose Yabby, Cherax setosus (Riek, 1951). Photograph of large male specimen (39.65 mm OCL, 37 gram, ACP 2646). The distinctive patch of setae extending across the outer half of the ventral surface of the propodus (inset) is a reliable feature to readily distinguish the species in the field. In particular, the invading yabby C. destructor Clark, 1936 lacks this feature. management initiatives, we provide a remove ~50mm of substrate to allow for a trap detailed morphological description of Cherax to be set with the entrance holes below the setosus, record general information about waterline. Traps were set for up to one hour, its distribution and ecology, and discuss or left overnight and checked the following conservation and management considerations. morning. Both opera house traps (630mm x 470mm x 180mm, 90mm entrance hole) and box traps (430mm x 260mm x 260mm, 40mm Materials and Methods entrance hole) were used, with a variety of Crayfish surveys were undertaken as baits including assorted meats, fish, dried dog part of both the broad Australian Crayfish biscuits and wet dog food sausage. Project (ACP) and a targeted sub-project on Spotlight surveys were undertaken at Cherax setosus (Project #100045, Australian some sites but yielded a limited number of Aquatic Biological 2008). Site co-ordinates specimens, and were generally found to be and altitude were recorded using a Magellan unproductive. Scoop nets were used to sample Explorist 600 handheld GPS. Crayfish were some sites that held sufficient water. At sites collected using a variety of methods to suit with insufficient water for other methods, the conditions at each survey site. Because manual excavation of burrows with a spade Cherax setosus inhabits ephemeral habitats, or trenching tool was required to retrieve the use of traps was largely restricted to animals. periods following storm events, when Voucher material was retained where ephemeral sites contained sufficient water appropriate, and all retained specimens depth for the physical trap dimensions. At were placed in transport containers with a some very shallow sites, a spade was used to small amount of water and some vegetation THE SETOSE YABBY, CHERAX SETOSUS 3 Fig. 2. Distribution of the Setose Yabby, Cherax setosus (Riek, 1951), indicated with black circles. Translocated populations of C. destructor Clark, 1936 are depicted with an ‘X’. Rivers, lakes and wetlands are shaded grey. from the site and returned to the laboratory. digital Vernier callipers. Other abbreviations Specimens were then euthanized by freezing include: AM, Australian Museum; NSW, New for at least 24 hours and subsequently stored South Wales. in clear, labelled specimen jars containing 70% ethanol. Tissue samples were retained Results in cell lysis buffer from selected specimens for subsequent DNA analysis, as part of the Distribution and Biology broader ACP. Specimens of C. setosus were recorded Voucher material was compared from numerous sites in lowland (<200m with specimens of two similar taxa from a.s.l.), coastal habitats between Taree and Queensland and Victoria (O’Brien et al., Morisset (Fig. 2), a northeast-southwest 2009; McCormack and Raadik, unpublished distance of around 150km. The main drainage data), and with specimens of the inland basins within that range are the Hunter, species Cherax destructor. A thorough Karuah and Myall Rivers. Its distribution morphological description was prepared for penetrates inland to areas near Cessnock and C. setosus based on this retained voucher Singleton, although it appears to be present material and the type material, held at the in much lower densities in these inland Australian Museum. Measurements of areas. We determined the overall extent of Propodal Length (PL), Propodal Width (PW), occurrence (EOO) for the species in this Total Carapace Length (TL) and Ocular study to be approximately 5,800km2, the Carapace Length (OCL) were made using third largest distribution of all Cherax species 44 R. B. MCCORMACK & J. COUGHRAN found in New South Wales. National Park, NSW (32.39°S 151.73°E), collected by R.B. McCormack, 23rd November 2008. ACP 1572, Male (OCL 25.66mm), Taxonomic Description corner Blackhill Rd and J Renshaw Dr, Cherax setosus (Riek 1951) NSW (32.82°S 151.58°E), collected by R.B. (Figs. 1 and 3) McCormack, 28th November 2008. ACP 1577, Female (OCL 30.15mm), Swamp Creek, HOLOTYPE: AM P4739, Male (OCL Neath, NSW (32.82°S 151.42°E), collected 34.35mm), Booral, Karuah River, Port th by R.B. McCormack, 28 November 2008. Stephens, NSW (32°29’S 151°58’E), th ACP 1582, Male (OCL 33.01mm), Vincent collected by D.G. Stead, 10 November St, Cessnock, NSW (32.85°S 151.35°E), 1911. PARATYPE: AM P4740, Male th collected by R.B. McCormack, 28 (OCL 31.63mm), Booral, Karuah River, November 2008. ACP 1601, Female (OCL Port Stephens, NSW (32°29’S 151°58’E), th 36.33mm), drain along Mt Faulk Rd, NSW collected by D. G. Stead, 10 November (32.03°S 151.46°E), carrying eggs, collected 1911. TOPOTYPES: AM P4741, 2 Males th by R.B. McCormack, 28 November 2008. (OCL 12.38-18.76mm), 2 Females (OCL ACP 1637, Male (OCL 24.92mm), Stoney 16.25-18.62mm), Booral, Karuah River, Ck, Blackalls Park, NSW (33.00°S 151.56°E), Port Stephens, NSW (32°29’S 151°58’E), nd th collected by R.B. McCormack, 2 December collected by D.G. Stead, 10 November 1911. 2008. ACP 2153, Male (OCL 43.15mm), Other Material Examined.– AM P4675, Swamp, Old Swan Bay Rd, Wallaroo State 2 Females (OCL 19.69-21.66mm), creek Forest, NSW (32.67°S 151.89°E), collected near Newcastle, NSW (32°56’S 151°46’E), th by R.B. McCormack, 24 June 2009. ACP collected by D.G. Stead, May 1907. AM 2154, Male (OCL 43.16mm), Swamp, P72105, Male, OCL 39.43mm, Tea Gardens, Old Swan Bay Rd, Wallaroo State Forest, NSW (32°40’S 152°10’E), collector NSW (32.67°S 151.89°E), collected by unspecified, February, 1977. AM P16819, th R.B. McCormack, 24 June 2009. ACP 3 Males (OCL 26.42-32.32mm), 7 Females 2156, Male (OCL 40.00mm), Swamp, (OCL 23.23-35.14mm), from burrows in Old Swan Bay Rd, Wallaroo State Forest, side of dam, Pokolbin (10 miles west of NSW (32.67°S 151.89°E), collected by Cessnock), Hunter Valley, NSW (32°48’S th R.B. McCormack, 24 June 2009. ACP 151°17’E), 1 with young, collected by D. 2157, Male (OCL 46.58mm), Swamp, Beeman, 1st February 1969. ACP 513, Male Old Swan Bay Rd, Wallaroo State Forest, (OCL 37.88mm), Swan Bay, NSW (32.66°S NSW (32.67°S 151.89°E), collected by 151.89°E), collected by R.B.