PROJECT 249 Status of Rare Fish A Literature Review of Freshwater Fish in the UK Institute of Freshwater Ecology National Rivers Authority Guardians of R&D Report 18 the Water Environment Status of Rare Fish A Literature Review of Freshwater Fish in the UK IJ Winfield, J M Fletcher and D Cragg-Hine Research Contractor: Institute of Freshwater Ecology National Rivers Authority Rivers House Waterside Drive Aztec West Almondsbury Bristol BS12 4UD LONDON: HMSO ENVIRONMENT AGENCY R&D Report 18 072875 National Rivers Authority Rivers House Waterside Drive Aztec West Bristol BS12 4UD Tel: 01454 624 400 Fax: 01454 624 409 © National Rivers Authority 1994 First Published 1994 ISBN 0-11-886511-0 All rights reserved. No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior permission of the National Rivers Authority. The views expressed in this document arc not necessarily those of the NRA. Its officers, servants or agents accept no liability whatsoever for any loss or damage arising from the interpretation or use of the information, or reliance on views contained herein. Dissemination status Internal: Released to Regions External: Released to Public Domain Statement of use The information contained in this report is for use by NRA staff and others involved in the management of endangered fish species within Britain, in particular the Corego««i species. Research contractor This document was produced under NRA R&D Projcct 249 by: The Institute of Freshwater Ecology The Windermere Laboratory Far Sawrey Ambleside Cumbria LA22 OLP Tel: 015394 42468 Fax: 015394 46914 Project Leader The NRA’s Project Leader for R&D Project 249 was: David Cragg-Hine - NRA North West Region. Cover photograph of a vendace, Coregonus albula, courtesy of the Institute of Freshwater Ecology. This document was designed by: Stotts, 14 Frederick Place, Clifton, Bristol; and printed by TL Visuals, Rainbow Court, Armstrong Way, Yate. R&D Report 18 CONTENTS Page Executive Summary v Key Words v -1. Introduction 1 2. Methods 2 3. Rare British Freshwater Fishes 3 3.1 Conservation background 3 3.2 Rare species lists 3 3.3 Brief species rarity notes 5 3.4 Conclusions 6 4. Taxonomic Relationships of Coregonus Species 7 5. Occurrence of Coregonus Species 8 _6._Popu!ation.Biology.of-Coregom/$Species---------------------------------------------- 9----- 6.1 General aspects 9 6.2 Coregonus species outside Britain 9 6.3 Coregonus species in Britain 11 7. Reproduction of Coregonus Species 13 7.1 General aspects 13 7.2 Coregonus species outside Britain 13 7.3 Coregonus species in Britain 15 8. Feeding of Coregonus Species 18 8.1 General aspects 18 8.2 Coregonus species outside Britain 18 8.3 Coregonus species in Britain 20 9. Seasonal Distribution of Coregonus Species 22 9.1 General aspects _ 22 9.2 Coregonus species outside Britain 22 9.3 Coregonus species in Britain 23 R&D Report 18 10. Introspecific Variation in Coregonus Species 25 10.1 General aspects 25 10.2 Phenotypic variation 25 10.3 Genotypic variation 25 11. Breeding 27 11.1 General aspects 27 11.2 Conservation aspects 27 11.3 Practical aspects 27 11.4 Coregonus species in Britain 29 12. Conclusions on Coregonus Species 30 13. Concluding Remarks on Rare British Freshwater Fishes 31 References 32 List of Tables 3.1 The native British freshwater fish fauna 4 3.2 List of rare or potentially rare British freshwater fishes 5 List of Figures 4.1 Coregonus albula, vendace 7 4.2 Coregonus lavaretus, schelly, powan, gwyniad 7 R&D Report 18 iv EXECUTIVE SUMMARY Members of the Coregonus genus have been extensively studied in lakes of Europe and North America, A literature review was undertaken to identify reflecting the wide geographical distribution of these freshwater fish species which may be endangered in species, where they are exploited in commercial Britain, and to review existing knowledge of whitefish fisheries. Taxonomic relationships within the genus are (Coregonus spp.) ecology, genetic variability and still under investigation, partly as a result of the artificial breeding techniques. Literature published up to considerable intraspecific variation displayed by its December 1993 inclusive was covered, resulting in the members. Populations are relatively long-lived, although examination of c. 600 articles of which c. 200 arc cited in marked fluctuations or oscillations in abundance are this review. The comprehensive reference list was also common. Spawning usually occurs in shallow inshore produced on disk in ASCII file format. areas in the autumn, although some spring-spawning populations are known, with hatching taking place in In addition to the vendace Coregonus albula, whitefish the following spring. Zooplankton'is an'important C. lavaretus (more specifically known as schelly, component of the diet, although benthic gwyniad or powan), burbot Lota lota and allis shad macroinvertebrates are also taken. Both C. albula and Alosa alosa, which are all protected by the Wildlife and C. lavaretus inhabit the hypolimnion of lakes during the Countryside Act 1981, several other freshwater or day, rising at dusk to feed, but the latter species may estuarine species are also rare. Of the British freshwater also frequent the littoral zone. Techniques for the fishes with marine affinities, the sturgeon Acipenser artificial breeding of Coregonus species have developed sturio, twaite shad Aloso fallax, houting Coregonus significantly in recent years with the result that they oxyrinchus and smelt Osmerus eperlanus should be may now be reared under intensive aquaculture considered for future research. Within the strictly conditions on an exclusively artificial diet. freshwater group, the Arctic charr Salvelinus alpinus requires immediate conservation action, as may the KEY WORDS spined loach Cobitis taenia. To these species may be added rudd Scardinius erythropbthalmus, crucian carp Literature review, rare fish, endangered fish, Coregonus Carassius carassius and silver bream Blicca bjoerkna albula, Coregonus lavaretus, vendace, schelly, gwyniad, which, although currently common in parts of Britain, conservation, eutrophication, species introductions. are considered to be under varying degrees of threat in Europe as a whole. R&D Report 18 v 1. INTRODUCTION with the major difficulty being the production of an objective rare species list for the present day. The aim of this literature review as stated in the Terms of Reference of the project is to review the extent of In contrast, the whitefish (Coregonus spp.) literature existing knowledge of whitefish ecology and genetic now amounts to at least hundreds and probably variability and of techniques for their artificial breeding thousands of articles. However, the vast majority of and rearing. In addition, the Terms of Reference also these publications originate from continental Europe require that this review should identify other species and North America, usually with fishery themes, and so which may be endangered in Britain and could be the their conclusions are not all directly applicable or subject of future research. relevant to the present review. With respect to the latter objective, considerations of A review of this nature could easily become tod long fish conservation are a relatively recent develop_ment and and exhaustive to be of practical use for the purpose for for a number of reasons lag behind most other areas of which it is intended. Consequently, at all times the animal conservation (Tudge 1990). This is particularly information reproduced here has been critically edited true of the U.K., with the result that the literature on to meet the aim of the Overall Project Objectives so that rare British freshwater fishes per se is very restricted. it helps to gather the information on these fish which is Thus, reviewing this field is relatively straightforward, necessary to safeguard their populations. R&D Report 18 1 2 . METHODS taxonomic basis, with major divisions being taxonomic relationships, ecology (occurrence, population biology, This review was carried out through extensive use of the reproduction, feeding and seasonal distribution), Library of the Freshwater Biological Association variation and breeding. housed at the Windermere Laboratory of the Institute of Freshwater Ecology, together with the authors’ In addition to the above published literature, there are personal reprint collection and, most importantly, direct also a number of unpublished Ph.D. theses dealing with contacts with individuals currently working in relevant the British coregonids. In rcccnt years, the feeding, areas. The latter approach is particularly important with growth and reproductive physiology of the powan respect to breeding studies, where developments can be (C. lavaretus) have been studied by Pomeroy (1987), very rapid, and in assessing the current rarity status of Brown (1989) and Rashid (1984) respectively, while the British freshwater fishes. Several as yet unpublished general biology of the gwyniad (C. lavaretus) was manuscripts were thus made available during the course investigated some time ago by Haram (1968). The of this review. The review was initially carried out in biology of the vendace (C. albula) and schelly late 1990, but it was subsequently updated in January (C. lavaretus) in the English Lake District were studied 1994 to cover all literature acquired by the Library recently by Mubamba (1989). during the intervening period. Unfortunately, the initial literature search revealed only Given the two major objectives, the review comprises three publications from the above theses, these being two main parts. Firstly, British freshwater fishes are Haram (1965) and Haram and Jones (1971) from Haram considered against a more general conservation (1968) and Brown and Scott (1990) from Brown (1989), background, and those which may now be considered while the update revealed the two additions of Brown et rare are specified and their classification briefly justified. al. (1991) from Brown (1989) and Pomeroy (1991) from Secondly, a more detailed review of Coregonus biology Pomeroy (1987).