South Australian River Murray Regional Wetlands Fish Assessment 2003–2012 Scotte Wedderburn The University of Adelaide Lara Suitor Department of Environment and Natural Resources Report to the South Australian Murray–Darling Basin Natural Resources Management Board June 2012 i ii This report may be cited as: Wedderburn, S. and Suitor, L. (2012). South Australian River Murray Regional Wetlands Fish Assessment. Report to the South Australian Murray–Darling Basin Natural Resources Management Board. The University of Adelaide, Adelaide, 54. © South Australian Murray–Darling Basin Natural Resources Management Board. This work is copyright. Graphical and textual information in the work (with the exception of photographs and the SA MDB NRM Board 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 (insert report title) 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 purposed is prohibited. Disclaimer Although reasonable care has been taken in preparing the information contained in this publication, neither the South Australian Murray–Darling Basin Natural Resources Management Board nor the other contributing authors accept any responsibility or liability for any losses of whatever kind arising from the interpretation or use of the information set out in this publication. iii iv Contents Summary ............................................................................................................................................................... 1 Introduction .......................................................................................................................................................... 3 Methods ................................................................................................................................................................. 6 Study regions ..................................................................................................................................................... 6 Time periods ...................................................................................................................................................... 7 Fish sampling ..................................................................................................................................................... 8 Data analyses ..................................................................................................................................................... 9 Results .................................................................................................................................................................... 9 Region 1 (State border – Overland Corner) ..................................................................................................... 11 Ordination ................................................................................................................................................... 11 Indicator species analysis ............................................................................................................................ 12 Region 2 (Overland Corner – Blanchetown) ................................................................................................... 13 Ordination ................................................................................................................................................... 13 Indicator species analysis ............................................................................................................................ 14 Region 3 (Blanchetown – Wellington) ............................................................................................................ 15 Ordination ................................................................................................................................................... 15 Indicator species analysis ............................................................................................................................ 16 Region 4 (Lower Lakes) .................................................................................................................................. 17 Ordination ................................................................................................................................................... 17 Indicator species analysis ............................................................................................................................ 18 Threatened fishes ............................................................................................................................................. 19 Murray hardyhead ....................................................................................................................................... 19 Southern pygmy perch ................................................................................................................................ 21 Yarra pygmy perch ...................................................................................................................................... 22 Southern purple-spotted gudgeon................................................................................................................ 23 Congolli....................................................................................................................................................... 25 Silver perch ................................................................................................................................................. 27 Freshwater catfish ....................................................................................................................................... 28 Golden perch ............................................................................................................................................... 30 Alien fishes ...................................................................................................................................................... 32 Carp ............................................................................................................................................................. 32 Goldfish....................................................................................................................................................... 34 Redfin .......................................................................................................................................................... 36 Gambusia .................................................................................................................................................... 38 Oriental weatherloach ................................................................................................................................. 40 Discussion ............................................................................................................................................................ 41 Objective 1: Shifts in regional wetland fish communities ............................................................................... 41 Objective 2: Threatened fish species ............................................................................................................... 42 Murray hardyhead ....................................................................................................................................... 42 Southern pygmy perch ................................................................................................................................ 43 Yarra pygmy perch ...................................................................................................................................... 43 Southern purple-spotted gudgeon................................................................................................................ 44 Congolli....................................................................................................................................................... 44 Silver perch ................................................................................................................................................. 45 Freshwater catfish ....................................................................................................................................... 45 Golden perch ............................................................................................................................................... 46 Objective 3: Alien fish species ........................................................................................................................ 46 Carp ............................................................................................................................................................. 46 Goldfish....................................................................................................................................................... 47 Gambusia .................................................................................................................................................... 47 Redfin .........................................................................................................................................................