[Freshwater Pearl Mussel's Personality]

by

ACKNOWLEDGEMENT

I would take this opportunity to thank my research supervisor, family and friends for their support and guidance without which this research would not have been possible.

DECLARATION

I, [type your full first names and surname here], declare that the contents of this dissertation/thesis represent my own unaided work, and that the dissertation/thesis has not previously been submitted for academic examination towards any qualification. Furthermore, it represents my own opinions and not necessarily those of the University.

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ABSTRACT

Samples of salmonids were taken from six Scottish rivers and examined for freshwater mussel (Margaritifera margaritifera (L.)) glochidiosis. The prevalence and magnitude of natural infections observed were comparable to those reported elsewhere. In most rivers, older fish seem to be less susceptible than 0+ fish, possibly due to an acquired immunity resulting from previous exposures. Initial infection loads may be greater on older fish due to greater ventilation rates and/or gill surface areas. However, this host size effect appears to be transitory. In a stock of farmed 0+ salmon, an entire parasitic stage was monitored. This took up to 11 months and only 5-10% of the initially attached glochidia managed to metamorphose and excyst as juvenile mussels. There are apparent differences in host utilisation between salmon and trout in certain rivers. Some trout stocks appear to be underutilised by M. margaritifera, possibly due to differences in behaviour and/or spawning site. 0+ salmon are the most important hosts in several rivers. However, there are a number of mussel populations located in small streams which have no salmon, and these are entirely trout-dependent. This may be important in terms of conservation, with regard to the recent collapse of migratory trout stocks in Scotland. Hyriopsis cumingii (Lea, 1852) is a freshwater mussel of major commercial importance for pearl culture in China. In this study, five polymorphic microsatellites from H. cumingii were identified and employed to investigate the occurrence and frequency of multiple paternity in 15 H. cumingii broods caught from Poyang Lake, China. The allele number of each locus ranged from 12 to 25, with a mean of 16.8 ± 5.4 alleles per locus. Multiple paternity was discovered in 10 broods by genotyping the dam mussel and the offspring from each brood. The sire number inferred by COLONY software in the 10 broods ranged from 2 to 4 with a mean of 2.7 ± 0.26 sires per brood. In 6 of the 10 broods, sires contributed skewed numbers of offspring (P < 0.05). These factors may be important for avoidance of inbreeding, optimization of genetic variation in offspring and for the persistence and evolution of H. cumingii.

TABLE OF CONTENTS

ABSTRACTI

CHAPTER 1: INTRODUCTION1

River B as an Optimal Biotope for Freshwater Pearl Mussel5

CHAPTER 2: MATERIALS AND METHODS9

Research Design9

First stage: test solitary mussels' reactions of single stimuli9

Second stage: controlled experiment10

Statistical analyses11

Site selection11

Examination of farmed fish12

Collection of gravid females and larval culture13

Development and Genotyping of Microsatellites14

CHAPTER 3: RESULTS15

Examination of wild fish15

Examination Of Farmed Fish18

CHAPTER 4: DISCUSSION AND ANALYSIS23

General observations25

Age-related differences25

Effect of host size28

Between-Species Comparisons28

CHAPTER 5: CONCLUSION33

REFERENCES34

CHAPTER 1: INTRODUCTION

Increased ...