Searching for threatened upland galaxiids in the Thomson and La Trobe river catchments, West Gippsland Arthur Rylah Institute for Environmental Research Technical Report Series No: 248 Published by the Victorian Government Department of Environment and Primary Industries Melbourne, July 2013 © The State of Victoria Department of Environment and Primary Industries 2013 This publication is copyright. No part may be reproduced by any process except in accordance with the provisions of the Copyright Act 1968. Authorised by the Victorian Government, Arthur Rylah Institute for Environmental Research, 123 Brown Street, Heidelberg VIC 3084. Print managed by Finsbury Green. Printed on recycled paper. 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Call us via the National Relay Service on 133 677 or visit www.relayservice.com.au This document is also available in PDF format on the internet at www.depi.vic.gov.au Report produced by: Arthur Rylah Institute for Environmental Research, Department of Environment and Primary Industries, PO Box 137 Heidelberg, Victoria 3084 Phone (03) 9450 8600 Website: www.depi.vic.gov.au/arthur-rylah- institute Citation: Raadik, Tarmo A. and Nicol, Michael D. (2013) Searching for threatened upland galaxiids (Teleostei, Galaxiidae) in the Thomson and La Trobe river catchments, West Gippsland, Victoria. Arthur Rylah Institute for Environmental Research Technical Report Series No. 248. Department of Environment and Primary Industries, Heidelberg, Victoria. Front cover photos: Main – Hope Creek, South Face Road, La Trobe River catchment; Upper – Tapered Galaxias (Galaxias sp. 8); Lower – West Gippsland Galaxias (Galaxias sp. 9) (Tarmo A. Raadik). Authorised by: Victorian Government, Melbourne Printed by: NMIT Print Room Searching for threatened upland galaxiids (Teleostei, Galaxiidae) in the Thomson and La Trobe river catchments, West Gippsland, Victoria Arthur Rylah Institute for Environmental Research Technical Report Series No. 248 Tarmo A. Raadik and Michael D. Nicol Arthur Rylah Institute for Environmental Research 123 Brown Street, Heidelberg, Victoria 3084 July 2013 Contents Acknowledgements ii Summary iii Introduction 1 Methods 3 Site selection 3 Aquatic fauna sampling 3 Results 6 Upland galaxiids 11 Other aquatic fauna 26 Discussion 35 Upland galaxiids 35 Other aquatic fauna 38 Conclusion 39 References 40 Appendix 1 Location of sampling sites 42 Appendix 2 Summary of survey results 46 Appendix 3 Summary of site characteristics 52 Arthur Rylah Institute for Environmental Research Technical Report Series No. 248 i Acknowledgements Funding for this project was provided by the (former) Department of Primary Industries, and facilitated by the Forests and Parks Division of the (former) Department of Sustainability and Environment. We especially thank Dr Lindy Lumsden (DEPI-ARI) for her support for the importance of the ‘wet bits’ in forested landscapes. We thank Greg Hollis (Baw Baw Shire Council), Mark Turra (Maintenance Supervisor, Mount Baw Baw Alpine Resort) and Stuart Galloway (Gippsland Water, formerly Maintenance Supervisor, Mount Baw Baw Alpine Resort) for information on previous anecdotal sightings of galaxiids on the Baw Baw Plateau. We thank Mark Turra for providing a Yamaha Rhino 4WD all-terrain vehicle to transport sampling equipment along the hiking trails on the Baw Baw Plateau, and sincere thanks is also extended to the chefs at the Village Restaurant in the Mount Baw Baw Alpine Resort who prepared warm food for us at any time of day to ward off hypothermia. We also thank Dale Archer (Melbourne Water, Thomson Reservoir Office), for arranging access to the Thomson River catchment, and Dave Vaskess (DEPI, Noojee), Jessica Taylor (DEPI, Heyfield) and Cliff Ireland (Parks Victoria, Dargo) for advice on track conditions and access issues. Silvana Acevedo (Arthur Rylah Institute) produced the GIS maps, and valuable critical comment on an earlier draft of this report was provided by Paul Reich and Jenny Nelson (Arthur Rylah Institute). This work was conducted under Fisheries Research Permit RP827 and FFG / National Parks research permit 10005451. Arthur Rylah Institute for Environmental Research Technical Report Series No. 248 ii Summary Whilst not a major landscape component based on area of occupancy, aquatic systems represent a different biome to terrestrial environments. Running waters, in particular, are an important and ubiquitous component of forested catchments, extending from lower elevations to ridgelines. They bisect the landscape into drainage or catchment units and support important vegetation communities (e.g. riparian zones) and aquatic organisms. The aquatic ecosystem relies on biological catchment processes, and in small upland streams in forested catchments, a major pathway of energy into the aquatic environment is from the riparian zone. As part of a project to develop an effective landscape approach to the management of threatened fauna that provides opportunities for sustainable timber production, improved information was needed on selected threatened aquatic fauna in the forest landscapes of the Central Highlands area in Victoria. Two species of native freshwater fish, considered threatened and restricted to forested catchments, were selected as priority taxa for field assessment. These species — Tapered Galaxias (Galaxias sp. 8) and West Gippsland Galaxias (Galaxias sp. 9), recently discovered as new species, are in the process of being formally described. These species were previously considered to be a single, morphologically variable species, the Mountain Galaxias (Galaxias olidus). Galaxias sp. 8 and Galaxias sp. 9 are each known from a short headwater section of a single narrow stream in state forest in the Thomson and La Trobe river catchments, respectively. They are considered to be critically endangered and have been nominated for listing under the Victorian Flora and Fauna Guarantee Act 1988. Predation by trout, introduced into Australia, is a key threatening process for upland galaxiids, typically eliminating them as they colonise new habitat, particularly in small streams. The species are also sensitive to instream sedimentation caused by catchment disturbance. The primary aim of this project was to confirm the presence and improve knowledge of Galaxias sp. 8 and Galaxias sp. 9 in the mid to upper portions (> 300 m elevation) of the Thomson and La Trobe catchments, including: . confirm previous distribution; . locate additional populations; . collect demographic and general habitat information; and, . assess potential threats, including wildfire and timber harvesting history. To value-add to this project and to improve broader aquatic biodiversity knowledge for the smaller streams in each catchment, data was also collected on additional aquatic fauna (other fish, crayfish and shrimp) encountered at each sampling site. Primary sampling sites were the locations at which these species had previously been recorded, including the Baw Baw Plateau where anecdotal information suggested the presence of an unidentified upland galaxiid. Additional survey sites, considered highly likely to harbour upland galaxiids, were selected across the upper Thomson and La Trobe catchments (e.g. sites not known to contain Brown Trout or Rainbow Trout, particularly those upstream of instream barriers such as waterfalls or steep instream gradients which would prevent trout access). One hundred and twenty sites were visited during February–May 2012, with 110 sites sampled, primarily by single-pass backpack electrofishing. This represents approximately 80% of the sites selected as likely to harbour upland galaxiids, which were recorded from only 4% of all sites visited. More than two-thirds of the sites sampled (n = 73) lacked fish, all mainly located in headwaters reaches of the La Trobe catchment, and 16 of these also lacked crayfish and shrimps. Galaxias sp. 8 and Galaxias sp. 9 were confirmed as present but restricted to the original single stream that they were each previously known from, and new data on their restricted distribution, threats, biology and habitat was collected. No additional populations of upland galaxiids were located, and their presence (or absence) on the Baw Baw Plateau could not be confirmed. This provides a high level of confidence that upland galaxiids are rare in terms of distribution in the forested catchments of the Thomson and La Trobe river systems. It also highlights how rare, and therefore significant, the few known populations of these galaxiids are, and how significant any additional populations would be if discovered. Within their restricted ranges, Galaxias sp. 8 was reasonably abundant, although Galaxias sp. 9 was rare and the species appears to have declined considerably in abundance since 2002. Both species are presumed to have