Reproduction and larval development of the New Zealand scallop, Pecten novaezelandiae. Neil E. de Jong A thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Science (MSc) 2013 School of Applied Science Table of Contents TABLE OF CONTENTS ...................................................................................... I TABLE OF FIGURES ....................................................................................... IV TABLE OF TABLES ......................................................................................... VI ATTESTATION OF AUTHORSHIP ................................................................. VII ACKNOWLEDGMENTS ................................................................................. VIII ABSTRACT ....................................................................................................... X 1 CHAPTER ONE: INTRODUCTION AND LITERATURE REVIEW .............. 1 1.1 Scallop Biology and Ecology ........................................................................................ 2 1.1.1 Diet ............................................................................................................................... 4 1.2 Fisheries and Aquaculture ............................................................................................ 5 1.2.1 Scallop Enhancement .................................................................................................. 8 1.2.2 Hatcheries .................................................................................................................. 10 1.3 Aims of this thesis ....................................................................................................... 11 2 CHAPTER TWO: BROODSTOCK CONDITIONING OF SCALLOPS. ..... 12 2.1 Introduction .................................................................................................................. 13 2.1.1 Biology ....................................................................................................................... 13 2.2 Broodstock conditioning............................................................................................. 14 2.2.1 Measures of gonad condition .................................................................................... 14 2.2.2 Colour ........................................................................................................................ 15 2.2.3 Spawning and post spawning .................................................................................... 15 2.2.4 Photoperiod................................................................................................................ 16 2.2.5 Temperature .............................................................................................................. 17 2.2.6 Diet ............................................................................................................................. 17 2.3 Aim ................................................................................................................................. 18 i 2.4 Methods and Materials ................................................................................................ 18 2.4.1 Animal collections ...................................................................................................... 18 2.4.2 Feeding experiment ................................................................................................... 18 2.4.3 Feeding rations .......................................................................................................... 21 2.4.4 Weight measurements ............................................................................................... 21 2.4.5 Gonad colour analysis ............................................................................................... 22 2.4.6 Visual grading index .................................................................................................. 23 2.4.7 Histological analyses ................................................................................................. 25 2.4.8 Acini and egg analysis ............................................................................................... 26 2.4.9 Statistics ..................................................................................................................... 28 2.5 Results .......................................................................................................................... 29 2.5.1 Feeding rations .......................................................................................................... 29 2.5.2 Mortality ..................................................................................................................... 29 2.5.3 Total tissue wet weight .............................................................................................. 29 2.5.4 Net tissue dry weight ................................................................................................. 30 2.5.5 Gonad wet weight ...................................................................................................... 32 2.5.6 Gonadalsomatic index ............................................................................................... 33 2.5.7 Colour ........................................................................................................................ 34 2.5.8 Male gonad colour ..................................................................................................... 35 2.5.9 Female gonad colour ................................................................................................. 36 2.5.10 Visual gonad index ................................................................................................ 37 2.5.11 Histological gonad index ....................................................................................... 38 2.5.12 Acini area ............................................................................................................... 40 2.5.13 Egg area ................................................................................................................ 41 2.5.14 Spawning ............................................................................................................... 42 2.6 Discussion .................................................................................................................... 44 2.6.1 Weight analyses ........................................................................................................ 44 2.6.2 Gonad development .................................................................................................. 44 2.6.3 Histological assessment ............................................................................................ 46 3 CHAPTER 3: TO CHARACTERISE LARVAL DEVELOPMENT (MORPHOLOGICAL, PHYSIOLOGICAL CHARACTERISTICS) OF THE NEW ZEALAND SCALLOP PECTEN NOVAEZELANDIAE FROM D-LARVAE TO PEDIVELIGER .................................................................................................. 48 3.1 Introduction .................................................................................................................. 49 3.1.1 Cultivation systems .................................................................................................... 50 3.1.2 Lifecycle ..................................................................................................................... 51 3.1.3 Spawning ................................................................................................................... 53 3.1.4 Larvae rearing ............................................................................................................ 54 ii 3.1.5 Larval feeding ............................................................................................................ 55 3.2 Aim ................................................................................................................................. 55 3.3 Methods and Materials ................................................................................................ 56 3.3.1 Broodstock ................................................................................................................. 56 3.3.2 Spawning procedure .................................................................................................. 57 3.3.3 Larval rearing and sampling ...................................................................................... 57 3.3.4 Light microscopy ........................................................................................................ 59 3.3.5 Scanning Electron Microscopy .................................................................................. 60 3.3.6 Sample analyses ....................................................................................................... 60 3.4 Results .......................................................................................................................... 61 3.4.1 Growth rates .............................................................................................................. 62 3.4.2 Clearance rates ......................................................................................................... 63 3.5 Embryogenesis ............................................................................................................ 64 3.5.1 Sperm .......................................................................................................................