• ,... t/.J:~40:Jf·iljj.;p11e ·eil£t coast aj· T«ts:lJiiini'ii:i\~~:::<:;'.·_. ' , <'" } ,.' ' ' ';.,. ... ~, ~ ... "" ,, ,.-;.~h', '<::..... ..._,"" ,,.,, > ... ,,:;~, , r ,< ,f' ~, '' < } ' ' ,, ', ,,, .... ~ ,::.",\" ,' ;";' ' ' ? ' ', ~· ,, ··' )'" "'subi:nitted. iri .,, '" ' '•,' /~ ' ' _·'Tasmanian Aqciaculture and Fisheries Institute-~,School o{Zo.plbgy, ', ~ ' - • ' " < Uniyersity·of Tasmania., ~ TNw-~ vJIElSFo/lt> f h. D. zoo ~ ll Declarations I hereby declare that this thesis is my own work, except where due acknowledgement is given, and that the material presented here has not been submitted at another university for the award of any other degree or diploma. This thesis may be made available for loan and limited copying in accordance with the Copyright Act 1968. ,. Dirk Cameron Welsford November 2003 iii [ iv Table of Contents DECLARATIONS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• III TABLE OF' CONTENTS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• v FIGURES AND TABLES •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• IX ACKNOWLEDGEMENTS •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• XIV ABSTRA.CT ••••• ••••• •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1 1. INTRODUCTION: THE ECOLOGY OF TEMPERATE WRASSES ........................... 4 Wrasse diversity .............................................................................................................. 4 Life-history strategies ..................................................................................................... 5 Biology and ecology of Notolabrus ................................................................................ 7 Wrasse fisheries .............................................................................................................. 8 Thesis outline ................................................................................................................. 9 2. A DESCRIPTION OF THE.EARLY LIFE-IDSTORY STAGES OF NOTOLABRUS FUCICOLA AND N. TETRICUS, AND OTHER TASMANIAN LABRIDS •••••••••••••••••••••••• 13 Introduction .................................................................................................................. 14 Materials and Methods ................................................................................................ 17 Eggs and reared larvae .................................................................................: ....................... 17 Wild caught larvae................................................................................................................. 17 Larval descriptions ........................................................................................... :.................... 18 Adult tissue ............................................................................................................................ 18 DNA extraction and PCR amplification ................................................................................ 19 RFLP analysis........................................................................................................................ 20 Post-settlement juveniles ....................................................................................................... 20 Juvenile pigment character analysis ..................................................................................... 21 v Results ........................................................................................................................... 22 Eggs and reared larvae ......................................................................................................... 22 Wild caught larvae ................................................................................................................ 25 Post-settlement Notolabrus spp ...................................................................................... : ...... 30 DNA extraction and PCR amplification ................................................................................ 30 RFLP analysis ....................................................................................................................... 31 Post-settlement pigment character analysis .......................................................................... 31 Discussion ..................................................................................................................... 35 Developmental series of Notolabrus spp. .............................................................................. 35 RFLP Analysis....................................................................................................................... 37 Post-settlement pigmentation analysis .................................................................................. 39 3. INTERPRETATION OF OTOLITH MICROSTRUCTURE IN THE EARLY LIFE· IDSTORY STAGES OF NOTOLABRUS FUCICOLA AND N. TETRICUS . ....................... 41 Introduction .................................................................................................................. 42 Materials and Methods ................................................................................................ 45 Larval rearing ....................................................................................................................... 45 Post-settlement fish ............................................................................................................... 46 Identification, measurement and curation ............................................................................ 47 Otolith analysis ..................................................................................................................... 47 Results ......................................................................................................................... :. 50 Larval rearing ....................................................................................................................... 50 Onset of increments ............................................................................................................... 50 Oxytetracycline marking ....................................................................................................... 51 Post-OTC increments ............................................................................................................ 52 Discussion ..................................................................................................................... 53 Onset of increments ............................................................................................................... 53 Validation of daily increments .............................................................................................. 56 Utility of otolith microstructure in Notolabrus spp ............................................................... 57 vi 4. SETTLEMENT DYNAMICS OF TE1\1PERA TE WRASSES ON THE EAST COAST OF TASMANIA········································································································· 58 Introduction .................................................................................................................. 60 Materials and Methods ................................................................................................ 62 ' Field sampling ....................................................................................................................... 62 Otolith analyses ..................................................................................................................... 65 Patterns of spawning, settlement and growth ........................................................................ 69 Results ........................................................................................................................... 70 Field sampling ..............................................•................. :...................................................... 70 Otolith analyses ..................................................................................................................... 71 Patterns of spawning, settlement and growth ....................................................................... 76 Discussion .................................................................... ,................................................ 84 Otolith morphology and microstructure ................................................................................ 84 Variability in planktonic larval duration ............................................................................... 85 Lunar periodicity in spawning and settlement dates ............................................................. 86 The influence of water temperature on settlement dynamics ................... :............................. 87 5. GROWTH OF A TE1\1PERATE, REEF-ASSOCIATED WRASSE (NOTOLABRUS FUCICOLA), ESTTh1ATED FROM AGE-AT-LENGTH AND TAG-RECAPTURE MODELS . .........................................................................................•....................... 93 Introduction .................................................................................................................. 94 Materials and Methods ...............................................................................................