THESTATUS OF THEATLANTIC SALMON INSCOTLAND INSTITUTEofTERRESTRIAL ECOLOGY NATURALENVIRONMENT RESEARCH COUNCIL ;".' (.3c1 2-1 1 t Natural Environment Research Council INSTITUTE OF TERRESTRIAL ECOLOGY LIBRARY CEti BANCHORY 1-{LLOF BRATHENS BANCHORY ABERDEENSHIRE, AB314BW The status of the Atlantic salmon in Scotland ITE symposium no. 15 Banchory Research Station 13 and 14 February 1985 Edited by DAVID JENKINS and WILLIAM M SHEARER Banchory Research Station Freshwater Fisheries Station BANCHORY MONTROSE Kincardineshire Tayside Printed in Great Britain by The Cambrian News, Aberystwyth © NERC Copyright 1986 Published in 1986 by Institute of Terrestrial Ecology Administrative Headquarters Monks Wood Experimental Station Abbots Ripton HUNTINGDON PE17 2LS BRITISH LIBRARYCATALOGUING-IN-PUBLICATION DATA The status of the Atlantic salmon in Scotland.—ITE symposium, ISSN 0263-8614; no 15 1. Atlantic salmon 2. Fishes—Scotland I. Jenkins, D. (David), 1926- II. Shearer, W. M. (William) III. Institute of Terrestrial Ecology 597'.55 0L638.S2 ISBN 0 904282 92 9 COVER ILLUSTRATION Male Salmon leaping at the Falls of Muick, Aberdeenshire — photogragh D. W. Hay, Freshwater Fisheries Laboratory, Pitlochry. Acknowledgements The symposium was planned by a steering committee composed of Dr P S Maitland (ITE), Mr J A Forster (formerly NCC), Prof David Jenkins (ITE), and Mr W M Shearer (DAFS). Abstracts were typed at and circulated from the Marine Laboratory of DAFS and all the papers were retyped by Mrs L M Burnett, ITE Banchory. Considerable help during the symposium was received from Dr N G Bayfield, MrJ W H Conroy and Mr A D Littlejohn, and Mrs L M Burnett and Mrs J Jenkins assisted with its organization. Mrs K B King checked the references and Mrs P A Ward helped with the final editing and proof-reading. The photographs were se)ected by Mr N Picozzi. The Institute of Terrestrial Ecology (ITE)was established in 1973, from the former Nature Conservancy's research stations and staff, joined later by the Institute of Tree Biology and the Culture Centre of Algae and Protozoa. ITE contributes to, and draws upon, the collective knowledge of the 14 sister institutes which make up the Natural Environment Research Council, spanning all the environmental sciences. The Institute studies the factors determining the structure, composition and processes of land and freshwater systems, and of individual plant and animal species. It is developing a sounder scientific basis for predicting and modelling environmental trends arising from natural or man-made change. The results of this research are availableto those responsible for the protection, management and wise use of our natural resources. One quarter of ITE's work is research commissioned by customers, such as the Department of Environment, the European Economic Community, the Nature Conservancy Council and the Overseas Development Administration. The remainder is fundamental research supported by NERC. ITE's expertise is widely used by international organizationsin overseas projects and programmes of research. Prof D Jenkins Mr W M Shearer Institute of Terrestrial Ecology DAFS Banchory Research Station Freshwater FisheriesStation Hill of Brathens, Glassel 16 River Street BANCHORY MONTROSE Kincardineshire Tayside AB3 4BY DD10 8DL 033 02 (Banchory) 3434 0674 (Montrose) 77070 1 Contents Preface 2 The law relating to salmon fishing 3 (R M Ross, Messrs Campbell, Middleton, Burness and Dickson, Solicitors, Montrose) The biology of Scottish salmon 10 (D H Mills, Department of Forestry and Natural Resources, University of Edinburgh) Changes in the timing and biology of salmon runs 20 (D A Dunk ley, DAFS, Freshwater Fisheries Laboratory, Pitlochry (Field Station, Montrose)) Aspects of open sea exploitation of Atlantic salmon and the problems of 28 assessing effects on Scottish home water stocks (R G J Shelton, DAFS, Freshwater Fisheries Laboratory, Pit !ochry) The exploitation of Atlantic salmon in Scottish home water fisheries in 37 1952-83 (W M Shearer, DAFS, Freshwater Fisheries Laboratory, Pitlochry (Field Station, Montrose)) Recent changes in fishing methods 50 (G N J Smart, Joseph Johnston and Sons Limited, Montrose) The management of a rod and line and a commercial fishery 55 (The Lord Thurso, Thurso East Mains, Thurso) The effect of the competition of farmed salmon in the market place on the 60 present state of commercial salmon fisheries (J R W Stansfeld, Joseph Johnston and Sons Limited, Montrose) Salmon farming and the future of Atlantic salmon 66 (L M Laird* and E A Needhamt * Department of Zoology, University of Aberdeen t Messrs Hayes McCubbin MacFarlane, Agricultural Consultants, Aberdeen) The potential impact of fish culture on wild stocks of Atlantic salmon in 73 Scotland (P S Maitland, Institute of Terrestrial Ecology, Bush Estate, Edinburgh) The data on salmon catches available for analysis in Norway 79 (L P Hansen, Directorate for Nature Management, Trondheim, Norway) The data available for analysis on the Irish salmon stock 84 (J Browne, Department of Fisheries and Forestry, Fisheries Research Centre, Castleknock, Dublin 15) An evaluation of the data available to assess Scottish salmon stocks 91 (W M Shearer, DAFS, Freshwater Fisheries Laboratory, Pitlochry (Field Station, Montrose)) Is there a basis here for prediction? 112 (J D Pirie, Department of Natural Philosophy, University of Aberdeen) Salmon population studies based upon Scottish catch statistics: statistical 116 considerations (K H Lakhani, Institute of Terrestrial Ecology, Monks Wood Experimental Station, Huntingdon) Summary 121 (A D McIntyre, DAFS, Marine Laboratory, Aberdeen) Appendix I: List of participants and contributors 126 2 Preface It may at first seem strange that a symposium on there seem to exist firmly entrenched but opposing Atlantic salmon should be held in an institute of views on the availability and dynamics of the Atlantic terrestrial ecology, particularly since in recent years salmon resource. On the one hand anglers were there has been a number of meetings on salmon, saying that there had been a disastrous decline in including some in central or northern Scotland. Howev- salmon numbers, while on the other hand the biolog- er, the divisions between scientists working on diff- ists were not sure whether there had been a real erent aspects of the environment are narrowing, and decline in stocks or whether it was part of a cyclical one of the encouraging developments in the scientific process. While there was no room for complacency, world is the ever more ready exchange of ideas there was difficulty in obtaining hard facts for this between terrestrial ecologists and fishery biologists paper, partly because these were not available to the and others who are interested in the total environment general public until recently and partly because there in which we live. It is proper that terrestrial ecologists were few or no data on the effort utilized in catching should not only interest themselves in the results of the fish which were said to be declining in numbers. the research of their colleagues in fishery research, but The situation was further complicated by changes in also understand the problems with which they are fishery methodology, by the different sorts of data faced, and consider whether their experience in a available for net fisheries in estuaries and in the sea different field can help to unravel problems in what and for rod and line fisheries on the rivers and lochs, may be technically more difficult habitats to study. The and by changes in the sea age groups of salmon that same applies the other way round, where, for exam- were being caught in different periods of years and in ple, work on marking marine mammals and big fish different river systems. has led to developments in electronic micro-engineer- ing of considerable interest to terrestrial scientists. The situation is obviously extremely complex, but this This liaison has encouraged further flourishing con- fact should not deter ecologists in one field from taking tacts between marine biologists and other ecologists an interest in the science of another. The decision to working on coastal species (sea-birds, otters). These hold this symposium having been taken, a small scientists are all interested in the small species of fish steering committee including members of the Fresh- which are eaten by a variety of wildlife but not yet water Fisheries Laboratory, ITE and the Nature Con- exploited commercially. servancy Council agreed that the subjects to be discussed should be as comprehensive as possible, The idea for the symposium developed when the including the regulation of the fishery, the biology of editors were invited to contribute a chapter for a book the fish, fishery methods, the statistics available on on the wildlife resource of Grampian Region, in a catches, and a comparison of views on the status of symposium volume edited by the Nature Conservancy salmonids in Scotland with those of other stocks of the Council and Grampian Regional Council under the fish in other countries. The large attendance of fishery auspices of the World Conservation Strategy. While it biologists at this meeting at a laboratory primarily was relatively easy to say something about the wildlife concerned with terrestrial biology augurs well, at the of the woods and mountains (though little was known least, for continued collaboration in the future. about the wildlife of agricultural land), difficulties arose when considering the exploitation of salmon, partly David Jenkins because of the political considerations associated with Brathens the management of this resource, but also because June 1985 3 The law relating to salmon fishing R M ROSS Messrs Campbell, Middleton, Burness and Dickson, High Street, Montrose 1 Introduction In theory at least, all land other than that held on a The proposition that the salmon, which by definition lease or tack is held ultimately of the Sovereign. The includes sea trout, has from time immemorial been a right to salmon fishing being inter regalia,all rights of valuable natural asset in Scotland (1) is supported by salmon fishing must be traceable to a grant by the the fact that, at Common Law, the right of salmon Crown.