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Durham E-Theses Durham E-Theses A study of the population biology of the British fresh water craysh austropotamoblus pallipes (lereboullet) Brown, Duncan K. How to cite: Brown, Duncan K. (1979) A study of the population biology of the British fresh water craysh austropotamoblus pallipes (lereboullet), Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/8265/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 A STUDY OF THE POPULATION BIOLOGY OF THE BRITISH FRESHVfATER CRAYFISH Austropotamobius palllpes (Lereboullet) by Duncan J. Brown, B.Sc. (Dunelm) Being a thesis submitted for the degree of Doctor of Philosophy of the University of Durham, March 1979 The copyright of this thesis rests with the author. No quotation from it should be published without Grey College, his prior written consent and information derived University of Durham from it should be acknowledged. 7 JUN WW SECTION ACKNOWLEDGEMENTS I would like to express my sincere thanks to Dr. K. Bowler for his advice, help and encouragement throughout this study and for his critical reading of the manuscript. I would also like to thank Dr. P. R. Evans and Dr. J. C. Coulson for their advice and Professor D. Barker for the use of the facilities in the Department of Zoology. This study would not have been possible without the co-operation of Newcastle and Gateshead Water Company; I am most grateful to thern and, in particular, to the reser.v_oir superintendents Mr. Tulip at — Hallington and Mr. Palmer at Whittle Dene. I would also like to express my gratitude to my wife, Suzi, for her encouragement, technical and clerical assistance during the work. My thanks also go to the technical and secretarial staff of the Department of Zoology and to Mrs. J. M. Towers for her skilful and accurate typing of this thesis. This study was sponsored by an N.E.R.C. research studentship. - ii - GLOSSARY 1. General abbreviations C.L. carapace length in mm. (see section 2.1) Pre M.C.L. premoult carapace length in mm. Post M.C.L. postmoult carapace length in mm. M.I. moult increment in mm. (Post M.C.L. - Pre M.C.L.) % M.I. percentage moult increment (M.I./ Pre M.C.L. x 100) PCF percentage cumulative frequency (Cassie 195*0 0+ age during the first year of life: thus 1+ and 2+ are the ages during the second and third years of life, and so on. CV calorific value of whole crayfish Pa estimated annual production for the whole population of A. pallipes in the aqueduct (Winberg 1971) B estimated mean annual biomass (Winberg 1971) - iii - 2. General statistical notation (see section 2.*+) c. t. contingency table d. f. degrees of freedom Y.C. Yates correction X chi squared t Students t SE standard error SD standard deviation p probability ra,c slope (m) and intercept (c) in a regression equation of the form: y = mx + c r Bravais-Pearson correlation coefficient 3. Categories of trapped samples (see section 6.2.h) b. ^ '75 Samples obtained by baited traps b. ^ '76 when the water level was not lowered between setting and emptying in 1975 and 1976. n.b. I '75 Samples obtained by non-baited n.b. ^ '76 traps when the water level was lowered between setting and emptying in 1975 and 1976. n.b. ^ '75 Samples obtained by non-baited traps when the water level was not lowered between setting and emptying in 1975• - iv - Statistical notation for the estimation of population parameters (see Chapters 5» 6 & 7 Lincoln index notation:- n-^ number of crayfish in the first sample n2 number of crayfish in the second sample m2 number of crayfish from the first sample recaptured in the second sample N estimate of the number of crayfish of carapace length ^ 13 mm. in the aqueduct-, usually applying to the time when the first sample was collected (see text). The notation of Jolly's stochastic model (1965):- n^ _ number captured in the i'th sample m^ number of marked crayfish in the i'th sample s^ number released from the i'th sample after marking A estimated total number of marked crayfish in the population at time i n^j number in i'th sample last captured (1 1) A in the j'th sample < J < i - Qi alpha; the estimated proportion of the population marked at time i A 0^ phi; the estimated probability that an animal alive at the moment of release of the i'th sample will survive till the time of capture of the i + l'th sample (emigration and death being synonymous for this purpose) estimated number of new animals joining the population in the interval between the i and i + l'th samples and alive at time i + 1 estimated number in the population when the i1th sample is captured - vi - CONTENTS Page Acknowledgements i Glossary ii Contents vi Abstract x General Introduction 1 Chapter 1 Description of the study area 1.1 Topography 9 1.2 Physical parameters of the study area 11 1.3 Biological parameters of the study area 13 Chapter 2 Methods 2.1 Measurements 17 2.2 Observations on the 'condition' of each animal 19 2.3 Marking techniques 21 2.?- Statistical methods 25 Chapter 3 The general biology of A,. paUlpes 3.1 Introduction 27 3.2 Geographical distribution 29 3.3 The life cycle in the aqueduct 31 3A Individual and population fecundity 38 3.5 Trophic relationships H7 - vii - Page 3.6 Displacements of crayfish in the study area 3.6.1 Migration into and out of the aqueduct 53 3.6.2 Displacements within the aqueduct 55 3.6.3 Diel activity patterns in the aqueduct 58 3.7 Infestation of A. pallipes in the aqueduct by the microsporidian parasite Thelohania conte.leani Henneguy 6l 3.8 The analysis of the body form of A. pallipes 66 Chapter k Growth of A. pallipes in the aqueduct and in the laboratory *f.l Introduction 70 k.2 Methods *+.2.1 Moult increments 73 k.2.2 Moult frequency 7k 3 Linear growth of A. pallipes in the aqueduct — — k\3«1 Moult increments" 75 W.3.2 Annual moult frequency 8k ^.3.3 Growth throughout the life cycle; the estimated inter• relationship between size and age 86 k.k Growth of A. pallipes in the laboratory ^A.l Laboratory methods 92 k.k.2 Moult increments 93 M-A.3 Moult frequency and survival 97 *+.5 Discussion 98 Chapter 5 The estimation of some of the parameters of the aqueduct population from the hand- collected samples 5.1 Introduction 116 5.2 General methods 129 - viii - Page 5.3 The preliminary study 1973-71*- 5.3.1 Introduction 131 5.3.2 Movement of marked crayfish 131 5.3.3 The size and structure of the hand-collected samples 133 5.3A Approximate population size estimates 133 5A The estimation of population parameters 1975-77 5 A.l' Introduction 137 5.h.2 The size and structure of the hand-collected samples 138 5A-3 Catch distribution along the aqueduct 1^0 The history of the tail marks lh2 5A.5 Mark-recapture analysis V*5 5.5 Discussion 153 Chapter 6 A methodological investigation of trapping as a sampling technique for A. pallipes in the aqueduct 6.1 Introduction l6l 6.2 General methods 162 6.3 Results 6.3.1 The size and structure of the trapped samples 165 6.3.2 Trap entry and escape 167 6.3.3 The variations in the number of crayfish trapped in different stretches of the aqueduct 172 6.3.I+ Seasonal variations in the proportion of females in the trapped samples 175 6.3.5 Mark-recapture analysis of the trapping data 176 6A Discussion 190 - ix - Paee Chapter 7 The estimation of the annual production of the crayfish population in the aqueduct in 1976 7.1 Introduction 198 7.2 Results 7.2.1 The estimation of annual production for crayfish of carapace length < 13 mm. 201 7.2.2 The estimation of annual production for crayfish of carapace length £ 13 mm. 205 7.2.3 The conversion of the estimate of production into energy units 209 7.3 Discussion 212 General Discussion 218 Bibliography 237 Appendix The composition of those samples of crayfish taken from the aqueduct which were included in the anal- — —- yses—presented in Chapters— - 5 and 6 263 - X - ABSTRACT The general biology and population dynamics of the fresh• water crayfish, Austropotamobius pallipes? were studied in a man- made aqueduct in Northumbria. The paucity of ecological knowledge of this species; the threat of the pathogenic crayfish 'plague* fungus, which has destroyed many European crayfish stocks; and several features of this aqueduct which made it particularly suitable for a population study inspired this investigation. The latter features were: the population was delimited to a known area (ca.
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