BIVALVE POPULATIONS IN FRESHWATER ENVIRONMENTS: VIABILITY, INVASION, PERSISTENCE AND A POTENTIAL ROLE IN THE SPREAD OF ANTIMICROBIAL RESISTANCE. Ben Strachan BSc. Marine Biology MSc. Marine Environmental Protection Submitted for the degree of Doctor of Philosophy Ulster University Faculty of Life and Health Sciences School of Geography and Environmental Sciences June 2019 I confirm that the word count of this thesis is less than 100,000 words. Contents Acknowledgements .......................................................................................................................... 1 Abstract ............................................................................................................................................ 2 Chapter 1. Introduction .................................................................................................................... 5 1.1 Project Rationale ................................................................................................................ 5 1.2 Thesis structure .................................................................................................................. 7 1.3 Aim, Hypothesis and Objectives ......................................................................................... 7 Chapter 2. Literature review .......................................................................................................... 11 2.1 Dreissena polymorpha (Zebra Mussels) .............................................................................. 11 2.1.1 Dreissena polymorpha distribution ............................................................................... 11 2.1.2 Dreissena polymorpha importance ............................................................................... 11 2.1.3 Dreissena polymorpha management ............................................................................ 14 2.2 Margaritifera margaritifera (Pearl Mussels) ...................................................................... 16 2.2.1 Margaritifera margaritifera distribution ....................................................................... 16 2.2.2 Margaritifera margaritifera decline .............................................................................. 19 2.2.3 Margaritifera margaritifera importance ....................................................................... 21 2.2.4 Margaritifera margaritifera protection ........................................................................ 22 2.3 Lough Neagh ........................................................................................................................ 23 2.3.1 Lough Neagh natural environment ............................................................................... 23 2.3.2 Lough Neagh regulatory environment .......................................................................... 24 2.3.3 Lough Neagh management of invasive species (Dreissena polymorpha) ..................... 25 2.3.4 Management of endangered species in the Lough Neagh catchment (Margaritifera margaritifera) ......................................................................................................................... 28 2.3.5 Lough Neagh management of water quality health ...................................................... 30 2.4 Importance of bivalves in aquatic ecosystems ..................................................................... 35 Chapter 3 Dreissena polymorpha in Lough Neagh ......................................................................... 37 Abstract ...................................................................................................................................... 37 3.1 Introduction ......................................................................................................................... 39 3.1.1 Importance of Lough Neagh and the potential impact of a zebra mussel invasion ...... 39 3.1.2 Dreissena polymorpha, the invader .............................................................................. 39 3.1.3 Dreissena polymorpha in Ireland ................................................................................... 41 3.1.4 Dreissena polymorpha in Lough Neagh – results from previous surveys ..................... 42 3.2 Methods ............................................................................................................................... 44 3.2.1 Larval Sampling .............................................................................................................. 44 3.2.2 Settlement panel, Snorkelling and Shoreline observations .......................................... 48 3.2.3 Parasites ........................................................................................................................ 51 3.2.4 Genetic analysis ............................................................................................................ 51 3.2.5 Substrate Suitability ...................................................................................................... 53 3.2.6 Estimate of total sedimentation rate from current regional wind data ....................... 53 3.3 Results ................................................................................................................................. 56 3.3.1 Larval sampling ............................................................................................................. 56 3.3.2 Settlement Panels ......................................................................................................... 64 3.3.3 Shoreline and Snorkelling Surveys ................................................................................ 68 3.3.4 Parasites ........................................................................................................................ 71 3.3.5 D. polymorpha in Northern Ireland sequencing for phylogenetic analysis .................. 72 3.3.6 Substrate Suitability ...................................................................................................... 75 3.3.7 Estimate of total sedimentation rate from regional wind data .................................... 79 3.3.8 Lough Neagh invertebrate abundance from larval sampling ....................................... 82 3.4 Discussion ............................................................................................................................ 84 3.4.1 Historic and recent data of zebra mussel presence in the Neagh Bann catchment ..... 84 3.4.2 Substrate suitability ...................................................................................................... 86 3.4.3 Wind driven water motion ............................................................................................ 87 3.4.4 Suspended particulate matter ...................................................................................... 88 3.4.5 Temperature, dissolved oxygen and electric conductivity ........................................... 90 3.4.6 Trophic Status of the Lake ............................................................................................ 93 3.4.7 Phytoplankton, lipid content and fatty acids ................................................................ 95 3.4.8 Parasitism ...................................................................................................................... 95 3.4.9 Competition for resources: Daphnia competition for calcium and food ...................... 97 3.4.10 Predation: Copepods .................................................................................................. 98 3.4.11 Conclusions ................................................................................................................. 99 Chapter 4 M. margaritifera glochidial survival on salmonids in the Ballinderry River ................ 101 Abstract ................................................................................................................................... 101 4.1 Introduction ....................................................................................................................... 102 4.1.1 Glochidial life history of M. margaritifera .................................................................. 102 4.1.2 M. margaritifera in the Ballinderry River .................................................................... 104 4.2 Materials and methods ..................................................................................................... 106 4.2.1 Ballinderry River natural glochidia count - River data ................................................ 106 4.2.2 Experimental site ........................................................................................................ 106 4.2.3 Species selection for hatchery trials ........................................................................... 107 4.2.4 Encystment trial layout ............................................................................................... 108 4.2.5 Fish selection for glochidial survival trial .................................................................... 113 4.2.6 Method for the glochidia count .................................................................................. 113 4.2.7 Glochidial size count .................................................................................................... 113 4.2.8 Environmental data and variables ............................................................................... 114 4.2.9 Fish