The copyright of this thesis vests in the author. No quotation from it or information derived from it is to be published without full acknowledgement of the source. The thesis is to be used for private study or non- commercial research purposes only. Published by the University of Cape Town (UCT) in terms of the non-exclusive license granted to UCT by the author. University of Cape Town A new sabellid that infests the shells of molluscs and its implications for abalone mariculture Thesis submitted in fulfilment of the requirements for Masters Degree in ScienceTown by Kevin RuckCape of April 2000 University Declaration A new sabellid that infests the shells of molluscs and its implications for abalone mariculture I hereby a) grant the University of Cape Town free licence to reproduce the above thesis in whole or in part, for the purpose of research b) declare that (i) the above thesis is my own unaided work, both in concept and execution, and apart from the normal guidance from my supervisor, I have received no assistance except as stated below: The cross-infection experiment in Chapter 3 was completed in collaboration with Dr. R.W. Day (Department of Zoology, University ofMelboume) The gelatin microcapsule preparations in Chapter 7 was made according to my specifications by the Polymers Programme, MATTEK, CSIR. A portion of the liposome work in Chapter 7 was done in collaboration with Mr Kurt Sales of the Department of Biochemistry, University of Cape Town. (n) neither the substance nor any part of the above thesis has been submitted by myself in the past, or is being, or is to be submitted for a degree in the University or any other university. Signature removed University of Cape Town 11 Acknowledgements Thanks to my supervisor Peter Cook for advice and guidance through the many years I have spent in his laboratory. It has been more than just the attaining of a degree, but a learning curve for life. I wish to thank the Abalone Farmers Association of South Mrica (AF AS A) for funding much of the research, and also making a bursary available towards my study costs. The FRD also provided a student bursary for 2 years. Rob Day for the interest and enthusiasm he has for natural science. Some of it has rubbed off I hope ... Carrie Culver and Armand Kuris for sharing their ideas and discoveries by Internet initially and later through friendship. Patience Xulu and Heidi Rolfes of the CSIR., MATTEK for supplying the microcapsules timeously and for being willing to adapt as needed.Town Lastly, to the residents of 13 Frankfort Road for sampling assistance on that epic field trip of 1997. Cape of University 111 CONTENTS ABSTRACT .................................................................................................................................... 1 CHAPTER 1 INTRODUCTION ..................................................................................................... 3 CHAPTER 2 DESCRIPTION ......................................................................................................... 6 2.1 IDSTORY ............................................................................................................................... 6 2.2 LIFE CyCLE ............................................................................................................................ 7 2.3 ADULT MORPHOLOGy ............................................................................................................. 9 2.3.1 Light microscopy .. ....................................................................................................... 9 2.3.2 Preparation of electron microscope sections (see Cross 1987} ..................................... 9 2.3.3 Observations ............................................................................................................. 10 2.4 LARVAL MORPHOLOGy ......................................................................................................... 13 2.5 SHELL AND BURROW MORPHOLOGy ....................................................................................... 13 CHAPTER 3 DISTRIBUTION...................................................................................................... 15 3.1 INTRODUCTION .................................................................................................................... 15 3.2 METHODS ............................................................................................................................ 15 3.2.1 Dive surveys: large-scale patterns ............................................................................. 15 3.2.2 Dive surveys: small-scale patterns ............................................................................. 17 3.2.3 SpeCial cases ............................................................................................................. 17 3.2.4 Export oflarvae from an abalone farm ......................................................................Town 19 3.2.5 O. sinensis crOSS-infection experiment.. ..................................................................... 19 3.3 RESULTS ............................................................................................................................. 20 3.3.1 Dive surveys: large scale patterns ............................................................................. 20 3.3.2 Dive surveys: small-scale patterns ............................................................................. 22 3.3.3 Special cases ........................................................................Cape ..................................... 24 3.3.4 Export oflarvae from an abalone farm ...................................................................... 27 O. sinensis crOSS-infection experiment........ .............................................................................of 28 3.4 DISCUSSION ......................................................................................................................... 29 CHAPTER 4 DISPERSAL............................................................................................................. 33 4.1 INTRODUCTION .................................................................................................................... 33 4.2 METHODS ............................................................................................................................ 33 4.2.1 Transfer oflarvae ...................................................................................................... 33 4.2.2 Sabellidfecundify ...................................................................................................... 34 4.2,3 Starvation .................................................................................................................. 35 4.2.4 Larval settlementUniversity ........................................................................... ............................ 35 4.3 RESULTS ................... , ................................................... , ....................................................... 35 4.3.1 Larval transfer ................................................................................ , ......................... 35 4.3.2 Sabellidfecundify ...................................................................................................... 39 4.3.3 Starvation ........................................................................... ,...................................... 40 4.3.4 Larval choice ............................................................................................................ 41 4.4 DISCUSSION ...................................................................... , .................................................. 42 CHAPTER 5 IMPLICATIONS FOR ABALONE MARICULTURE .......................................... 45 5.1 INFLUENCE ON GROWTH RATES ............................................................................................. 45 5.1.1 Methods ..................................................................................................................... 45 5.1.2 Results.............................................................. ......................................................... 46 5.2 OTHER IMPLICATIONS .......................................................................................................... 48 5.3 DISCUSSION ................................ , ........................................................................................ 49 CHAPTER 6 MANAGEMENT ..................................................................................................... 51 6.1 INTRODUCTION .................................................................................................................... 51 6.2 EXPOSURE ........................................................................................................................... 51 IV 6.2.1 Sources of infestation . ............................................................................................... 52 6.2.2 Transfer within afarm ............................................................................................... 53 6.3 MANAGING EXISTING INFESTATIONS ...................................................................................... 54 6.3.1 Stocking densities ...................................................................................................... 54 6.3.2 Water temperature ....................................................................................................