Sustainable Fisheries through Sustaining Fish Habitat - -------- -· -- - Department of Primary Industries and Energy Bureau of Resource Sciences Proceedings Sustainable Fisheries through Sustaining Fish Habitat Australian Society for Fish Biology Workshop Victor Harbor, SA 12-13 August 1992 Editor: D.A. Hancock Australian Government Publishing Service Canberra © Commonwealth of Australia1993 ISSN 1032-2469 ISBN O 644 29632 I This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Australian Government Publishing Service. Requests and inquiries concerningreproduction and rights should be addressed to the Manager, Commonwealth Information Services, Australian GovernmentPublishing Service, GPO Box 84, Canberra ACT 260 I. Preferredway to cite this publication: Hancock, D.A. (ed.)1993, Sustainable Fisheries through Sustaining Fish Habitat, Australian Society for Fish Biology Workshop, Victor Harbor, SA, 12-13 August, Bureau of Resource Sciences Proceedings, AGPS, Canberra. The Bureau of Resource Sciences is a professionallyindependent Bureau in the Department of Primary Industries and Energy. It was formedin October1992 from the existing Bureau of Rural Resources and the resource assessment branches of the former Bureau of Mineral Resources. The Bureau's role is to support the sustainable development of Australia's agricultural, mineral, petroleum, forestry and fisheries industries by providing scientific and technical advice to government, industry and the community. Bureau of Resource Sciences PO Box Ell Queen Victoria Terrace Parkes ACT 2600 Printed for AGPS by Pirie Printers Pty Limited, Fyshwick, A.C.T. FOREWORD J.G. Pepperell President Australian Society for Fish Biology This workshop, entitled "Sustainable Fisheries I believe that these workshops, and their through Sustaining Fish Habitat", continues the published Proceedings, are now recognised as Australian Society for Fish Biology's workshop benchmarks in the development of fish and series and its established tradition of bringing fisheries science in Australia. The present vol­ together the country's leading experts to freely ume is no exception. discuss specific fish and fishery themes of na­ The fisheries working group of the Federal tional importance. Past workshops have pre­ Government's Ecologically Sustainable Devel­ ceded the Society's Annual Conferences, and opment strategy noted that ... "management has began with a meeting on "Australian Threat­ to establish operating frameworks which em­ ened Fishes" in Melbourne in 1985. Themes brace both economic and environmental factors since then have covered diverse topics: "Ad­ ... (which) must ensure prudent management vances in Aquaculture", "The Use of By-catch which determines and implements the neces­ Resources in Australia", "Scientific Advice for sary arrangements and controls to safeguard the Managers: Getting the Message Across", "Tag­ resource and the environment in concert with ging - Solution or Problem?", "Introduced and sound development of the commercial indus­ Translocated Fishes and their Ecological Ef­ try". (To this I would add the recreational fish­ fects", "Legal Sizes and their use in Fisheries ing industry). In fact, the first nine of the working Management", "The Measurement of Age and group's recommendations relate to concerns for Growth in Fish and Shellfish", "Larval Biol­ ecosystems and fish habitat. ogy", and "Recruitment Processes". The primary aims of the Society's success­ Since 1988, the workshops have been gen­ ful application for funding to FRDC were: To erously supported by the Fishing Industry Re­ identify national fish habitat research needs, search and Development Council (now the and to clarify management's needs to fisheries Fisheries Research and Development Corpora­ scientists. The workshop attracted a record at­ tion, FRDC). This support has ensured the at­ tendance, encouraging lively and enthusiastic tendance of overseas experts at the workshops, debate, and I am confident that all present would and has allowed professional editorial treatment agree that those goals were met. of the published Proceedings. The Bureau of Rural Resources (now, Bureau of Resource Sci­ The keynote speaker at the workshop was ences, BRS) has also been most generous in Stan Moberly, a past President of the American contributing substantially to the costs of publi­ Fisheries Society, and formerly Director of the cation of Proceedings. Alaska Fisheries Department. I am sure you will Bureau of Resource Sciences Proceedings iii find his address in these proceedings both stimu­ lating and enlightening, and those present will remember his infectious zeal in relaying his experiences and concerns about fish habitat. In a letter to the Society after his returnto the U.S. he stated: "In my opinion, the health of a nation and the quality of lifeit offers its citizens can be judged by the health of its aquatic ecosystems." I'm sure a large majority of us would agree. During the workshop, an important new committee on Fish Habitat was formed. Con­ vened by Jenny Burchmore, this committee will play an important role in habitat protection and education in the future. Rob Lewis swung the resources of the South Australian Department of Fisheries behind the workshop and conference, and his assistance at all levels is greatly appreciated. The workshop organising committee, convened by Bairy Bmce, did a magnificent job, so many thanks also to him, together with Ene-Mai Oks, Keith Jones, Mervi Kangas, Gary Jackson and Kate Messner. I also wish to acknowledge the hard work of the editor, Don Hancock, and his persistence in gently prodding presenters, rapporteurs (and myself)to complete and forwardmanuscripts so that these Proceedings could be published at all, let alone, on time. He has been ably assisted by Gregg Berry of BRS. This volume continues the tradition set by previous workshops, and furthers the high stand­ ards which they have achieved. I commend it to you. iv Bureau of Resource Sciences Proceedings Contents Foreword J.G. Pepperell .................................................................................................................................. iii SESSION 1: Introduction Keynote Address: Habitat is Where It's At! "It's More Fun to Fight over More Fish than Less Fish" S.J. Moberly ...................................................................................................................................... 3 Discussion of Keynote Address Recorded by J.P. Glaister ............................................................................................................... 14 SESSION 2: A Manager's View of Fish Habitat Chairperson's Introduction R.K. Lewis ....................................................................................................................................... 19 An Ecosystem-based Approach to Marine Fisheries Management K.S. Edyvane ................................................................................................................................... 21 Estuarine Issues from the Manager's Viewpoint R.H. Winstanley .............................................................................................................................. 28 Freshwater Habitat Protection-A Manager's Perspective P.D. Jackson ................................................................................................................................... 32 Discussion of Session 2 Recorded by G.M. Newton .............................................................................................................. 35 SESSION 3: Organisms and Environmental Relationships I-Case Studies Chairperson's Introduction P.C. Gehrke .................................................................................................................................... 41 Maintain or Modify-Alternative Views of Managing Critical Fisheries Habitat I.R. Poiner, N.R. Loneragan and C.A. Conacher ........................................................................... 43 Rehabilitation, Mitigation and Restoration of Fish Habitat in Regulated Rivers S. Swales ......................................................................................................................................... 49 A Habitat Fit for Fish-An Aim ofBiomanipulation? M.T. Bales ....................................................................................................................................... 57 Enhancement of Estuarine Habitats in Association with Development R.M. Morton ................................................................................................................................... 64 Discussion of Session 3 Recorded by G.A. Thorncraft .......................................................................................................... 70 Bureau of Resource Sciences Proceedings V SESSION 4: Organisms and Environmental Relationships II-Key Variables and Broad Based Issues Chairperson's Introduction: Key Factors Linking Fish and Their Habitat B.E. Pierce ...................................................................................................................................... 75 Freshwater Fish Habitats: Key Factors and Methods to Determine Them J.D. Koehn ...................................................................................................................................... 77 Defining Key Factors Relating Marine Fishes