NATIVE SPECIES

Common Name Trout (Blue-nose cod) Threatened

Scientific Name macquariensis (Cuvier, 1829) Photo: Gunther Schmida

Identification fish are 0.75–1.5 kg and spawning occurs in A large, deep-bodied fish with a large mouth late spring (mid-October–mid-November). reaching to below the back of the eye. Fecundity is ~1200–11,000 eggs per female. Maximum size 16 kg and 850 mm; usually The eggs are large (2.5–3.6 mm diameter), < 5kg. The head profile is straight, and the adhesive, and probably deposited on hard upper jaw overhangs the lower. The tail is substrates such as logs and rocks. After 5–10 rounded and the pelvic fins are located below days, larvae of about 6–9 mm length hatch. the pectorals. The overhanging upper jaw and The diet includes fish, yabbies, mudeyes, a speckled body pattern which is blue-grey aquatic larvae, shrimps and freshwater rather than yellow-green, distinguishes this prawns. Recent research in the lowlands of the species from the otherwise similarly-shaped Murrumbidgee River has demonstrated that . Most individuals have a dark adults occupy small areas of less than 500 m stripe through the eye, although this feature is centred on a ‘home snag’, and occasionally also present in young Murray cod. undertake exploratory movements of 20–60 km involving a return to their home. Biology and Habitat Only formally recognised as a separate species Distribution and Abundance from Murray cod in 1972, some aspects of There are now only three self-sustaining the biology of Trout cod are poorly known. populations of Trout cod remaining in The species is usually associated with deeper the wild. The largest is in the Murray water (pools) and instream cover such as logs River between Yarrawonga and Barmah and boulders. In the , where (approximately 200 km of river), the others it is found with Murray cod, it occupies are small translocated populations present in slightly faster-flowing locations. Sexual Cataract Dam, and in about 15 km of the maturity is reached at 3–5 years of age when upper reaches of Sevens Creek near Euroa

78 Fishes of the Murray-Darling Basin An introductory guide 79 ID Valley 1 Avoca 2 Border Rivers 3 Broken 4 campaspe 5 castlereagh 6 central Murray 7 condamine 8 darling 9 goulburn 10 gwydir 11 Kiewa 12 Lachlan 13 Loddon 14 Lower Murray 15 Macquarie 16 Mitta Mitta 17 Murrumbidgee 18 namoi 19 ovens 20 Paroo 21 upper Murray 22 Warrego 23 Wimmera

in Vic. Because of early confusion regarding breeding has been recorded in the Goulburn the identification of Trout cod, information and Cotter rivers and is suspected in the mid- on the historic distribution of the species is Murrumbidgee River. unclear. Potential Threats Trout cod was originally described from the , where it has not been Threats include interactions with alien recorded since the 1820s, other than a single species such as trout and Redfin perch, and unconfirmed record from the Turon River habitat modification such as desnagging, in the 1970s. It was not known from the sedimentation, clearing of riparian vegetation, Darling River. Formerly widespread in the river regulation and cold-water pollution from southern Murray-Darling Basin (Murray, dams. Overfishing of remnant populations Murrumbidgee and Macquarie rivers, NSW/ has also contributed to declines and needs to ACT; Ovens, Goulburn, Campaspe, King, be carefully managed if reintroductions are to Buffalo, Mitta Mitta rivers, Vic; Murray be successful. River, SA), the species declined significantly General References in the 1970s. A long-term stocking program since the late 1980s has reintroduced Trout Berra & Weatherley 1972; Cadwallader & cod to a number of locations in the Basin Gooley 1984; Douglas et al. 1994; Ebner including sites on the Murrumbidgee, et al. 2006; Harris & Rowland 1996; Ingram Macquarie, Ovens, Goulburn, Tumut and & Rimmer 1992; King et al. 2005; Koehn upper Murray drainages. The species has also & Harrington 2006; Lintermans et al. 1988, been stocked in Bendora Reservoir, ACT, and 2005; Morris et al. 2001. Talbingo Reservoir, NSW. Unfortunately, these reintroductions have not resulted in the establishment of viable populations, although

78 Fishes of the Murray-Darling Basin An introductory guide 79 Published by the Murray-Darling Basin Commission Postal address: GPO Box 409, Canberra ACT 2601 Office location: Level 3, 51 Allara Street, Canberra City ACT Telephone: (02) 6279 0100, international + 61 2 6279 0100 Facsimile: (02) 6248 8053, international + 61 2 6248 8053 Email: [email protected] Internet: http://www.mdbc.gov.au For further information contact the Murray-Darling Basin Commission office on (02) 6279 0100 This fish fact sheet is an extract derived from the report: Lintermans, M. 2007, Fishes of the Murray-Darling Basin: An introductory guide. MDBC Publication No. 10/07 ISBN 1 921257 20 2 © Murray-Darling Basin Commission 2007 This work is copyright. Graphical and textual information in the work (with the exception of photographs, artwork and the MDBC logo) may be stored, retrieved and reproduced in whole or in part provided the information is not sold or used for commercial benefit and its source (Fishes of the Murray-Darling Basin) is acknowledged. Such reproduction includes fair dealing for the purpose of private study, research, criticism or review as permitted under the Copyright Act 1968. Reproduction for other purposes is prohibited without the permission of the Murray- Darling Basin Commission or the individual photographers and artists with whom copyright applies. To extent permitted by law, the copyright holders (including its employees and consultants) exclude all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this report (in part or whole) and any information or material contained in it.

ii Fishes of the Murray-Darling Basin