THE MURRAY-DARLING BASIN - PDF document

THE MURRAY-DARLING BASIN 122 122 THE MURRAY-DARLING BASIN I slightly-forked tail. Maximum 700 mm and nearly 9 kg; usually 100 – 300 mm. e head is large with a long, blunt snout and small, distinctively orange-red eyes. e mouth is small to moderate in size with a small barbel at each corner. e ns are rounded and thick. It has a single, short-based, high and rounded dorsal n, located in about the and covered with a heavy mucous. Usually, dark olive to pale golden or silvery in colour. Biology and e Tench avoids fast water and is typically found in slow-owing or still waters, often with a muddy bottom and abundant aquatic plants. It is often abundant in o-channel habitats, such as backwaters and lagoons, and in deep, sheltered holes. Adult Tench are predominantly benthic carnivores and their diet consists mainly of aquatic insects (commonly chironomids, mudeyes, mayies) and microcrustaceans (cladocera, ostracods, amphipods, copepods), with some molluscs, worms and plant material. Small Tench feed largely on microcrustaceans and small chironomids. Fry feed on plankton and small insect larvae and crustaceans. Tench may live for 20 30 years and reach maturity at 3 – 4 years. In rivers, growth is generally slow: sh from the Coal River in Tas reached lengths of approximately 29, 57, 93, 132, 172, 208, 239 and 261 mm at 1 to 8 years of age, respectively. Spawning occurs in spring and summer. Females produce large numbers (300,000 – 900,000) of small eggs (0.8 – 1.0 mm diameter) in 3 – 4 batches, at intervals of about two weeks. e eggs are adhesive and laid in shallow water, usually on weeds. Hatching occurs after 3 – 6 days and hatchlings are about 4 – 5 mm in length. ative Fish Little is known of the impacts of Tench on native sh species, but they are not thought to be signicant. Common ench ( Tinca tinca (Linnaeus, 1758) ALIEN Photo: Gunther Schmida 123 AN INTRODUCTORY GUIDE AN INTRODUCTORY GUIDE 123 Distribution and A e Tench is native to Europe, but was introduced to Australia in 1876. e species was originally widely distributed in Vic by acclimatisation societies and is still highly sought after by ‘coarse sh’ enthusiasts. In the Murray-Darling Basin, it is primarily restricted to Vic. It is rarely recorded in NSW, but was formerly present in the Murray, lower Murrumbidgee and lower Lachlan rivers. Since the arrival of Carp, Tench has become rare in the Basin in SA and rare or absent in NSW, and is not present in the ACT and Qld. G Brumley 1996; Cadwallader & Backhouse 1983; Clements 1988; Merrick & Schmida 1984; Weatherley 1959, 1962; Weatherley & Lake 1967. IVALL Avoca ivers Broken C C Central Murray C D G 10 G 11Kiewa 12Lachlan 13Loddon 14Lower Murray 15 16Mitta Mitta 17Murrumbidgee 18 N 19 O Paroo Upper Murray Warrego 23Wimmera Published by the Murray-Darling Basin Commission Postal address: GPO Box 409, Canberra ACT 2601 Oce 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: info@mdbc.gov.au Internet: http://www.mdbc.gov.au For further information contact the Murray-Darling Basin Commission oce on (02) 6279 0100 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 is 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 benet 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. FISHES O F THE MURRAY-DARLING BASIN ii