Queensland University of Technology School of Natural Resource Sciences FACTORS AFFECTING REPRODUCTIVE PERFORMANCE OF THE PRAWN, Penaeus monodon Gay Marsden Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy 2008 1 Statement of original authorship The work contained in this thesis has not been previously submitted to meet the requirement for an award at this or any other higher education institution. To the best of my knowledge and belief, the thesis contains no material previously published or written by another person except where due reference is made. Signature…………………………………….. Date…………………...................................... 2 Acknowledgments In terms of facilities I would like to acknowledge the extensive support of the Bribie Island Aquaculture Research Centre (BIARC), Queensland DPI&F. Funding for the research was gratefully received from FRDC and QUT. For valued friendship and technical support I am indebted to the BIARC staff and in particular Michael Burke. Valued statistical advice was given by David Mayer (DPI&F) and biochemical analysis was carried out by Ian Brock (DPI&F). Thanks also to: fellow student Phil Brady for his encouragement throughout all phases of the research and for his passion and willingness to partake in lengthy discussions on prawn reproduction; Peter Duncan for his kindness and patience while I made use of his kitchen table during the final stages; and to my three supervisors Dr Neil Richardson, Associate Professor Peter Mather and Dr Wayne Knibb for their unique contributions. Neils’ efforts to keep me on track deserve a medal. Lastly, thanks to my family for their understanding and financial support, particularly Ian Neilsen who in many ways provided the window of opportunity I needed to undertake this challenge. Keywords Penaeus monodon, prawn reproduction, ovary, eggs, hepatopancreas, mating, methyl farnesoate, ablation, captivity, sinus gland hormones, fatty acids, lipid, protein. 3 TABLE OF CONTENTS Chapter 1. INTRODUCTION...........................................................................................................10 Chapter 2. LITERATURE REVIEW 2.1 Aquaculture…………………………………………………………………………14 2.1.1 History of aquaculture systems…………………………………………...15 2.1.2 Animal species cultured in aquaculture…………………………...17 2.1.2.1 Prawn aquaculture……………………………………………….18 2. 2 Penaeus monodon………………………………………………………………21 2.2.1 Global production of Penaeus monodon…………………………………..21 2.2.2 Penaeus monodon farming in Australia……………………...……………22 2.2.3 Domestication of P. monodon……………………………………………..23 2.2.4 Life cycle and reproductive biology of P. monodon ………………………25 2.3 Ovary development and endocrine regulation……………………………………….27 2.3.1 Accumulation of nutrient reserves in the oocytes of penaeid prawns……..27 2.3.1.1 The process of vitellogenesis…………………………………….28 2.3.1.2 Cortical Rod formation…………………………………………..31 2.3.1.3 Patterns of nutrient fluctuation in hepatopancreas and ovaries….33 2.3.2 Endocrine regulation of reproduction in crustaceans………………………35 2.3.2.1 The CHH family of hormones…………………………………...37 4 2.3.2.2 The Roles of Methyl Farnesoate (MF) in prawn reproduction….40 2.3.3 Endocrine manipulation strategies employed in prawn aquaculture……….42 2.3.3.1 Eyestalk ablation…………………………………………………43 2.4 Mating Behaviour of Penaeid Species……………………………………………….45 2.4.1 Mating strategies of crustaceans……………………………………………….46 2.4.2 Mating strategies of closed and open thelycum species of penaeids…………..51 2.4.3 Mating behaviour of P. monodon ....... ..........................................................52 2.4.4 Mating in captive-bred prawns including P. monodon ………………… .... …52 2.5. Summary…………………………………………………………………………….56 2.6. Project hypothesis and aims…………………………………………………………59 Chapter 3. GENERAL METHODS 3.1 Prawns………………………………………………………………………………..62 3.1.1 Location……………………………………………………………………62 3.1.2 Capture method…………………………………………………………….62 3.1.3 Transport method………………………………………………………..…63 3.1.4 Arrival and acclimation…………………………………………………….64 3.1.5 Holding tanks………………………………………………………………64 5 3.1.6 Ablation…………………………………………………………………….65 3.1.7 Feeding……………………………………………………………………..65 3.2 Tissue, egg and larval collection, classification and biochemical analysis………….66 3.2.1 Tissue collection……………………………………………………………66 3.2.2 Classification of tissues using gonad somatic index (GSI) and hepatopancreas somatic index (HSI)………………………………………………………………66 3.2.3 Classification of ovary developmental stage using histology……………….67 3.2.4 Biochemical analysis………………………………………………………..67 Chapter 4. THE EFFECTS OF CAPTIVITY AND ABLATION ON PROTEIN, LIPID AND DRY MATTER CONTENT OF OVARY AND HEPATOPANCREAS TISSUES IN THE PRAWN PENAEUS MONODON. 4.0 Abstract……………………………………………………………………………….69 4.1 Introduction……………………………………………………………………………70 4.2 Methods……………………………………………………………………………….73 4.2.1 Prawns……………………………………………………………………...73 4.2.2 Holding Conditions for Captive Prawns……………………………………73 4.2.3 Statistical analysis…………………………………………………………..75 4.3 Results..………………………………………………………………………….........76 4.3.1 GSI and Biochemical Analysis……………………………………………..76 4.3.2 Histology…………………………………………………………………...78 6 4.4 Discussion………………………………………………………………………….…83 Chapter 5. THE EFFECTS OF ABLATION AND STARVATION OF THE PRAWN PENAEUS MONODON ON PROTEIN AND LIPID CONTENT IN OVARY AND HEPATOPANCREAS TISSUES. 5.0 Abstract……………………………………………………………………………….89 5.1 Introduction…………………………………………………………………………...91 5.2 Methods……………………………………………………………………………….93 5.2.1 Prawns………………………………………………………………………93 5.2.2 Holding conditions and experimental design……………………………….93 5.2.3 Statistical Analysis…………………………………………………………94 5.3 Results………………………………………………………………………………..95 5.4 Discussion…………………………………………………………………………...98 Chapter 6. METHYL FARNESOATE AS A POTENTIAL HORMONE FOR STIMULATING OVARY DEVELOPMENT AND INCREASING EGG HATCH RATE IN THE BLACK TIGER PRAWN, PENAEUS MONODON 6.0 Abstract..……………………………………………………………………………102 6.1 Introduction…………………………………………………………………………104 6.2 Methods……………………………………………………………………………..107 7 6.2.1. Prawns and holding conditions…………………………………………..107 6.2.2 Diets………………………………………………………………………108 6.2.3. Statistical analysis………………………………………………………..109 6.3 Results……………………………………………………………………..……… 110 6.4 Discussion……………………………………………………………...…………..115 Chapter 7. THE IMPACT OF CAPTIVITY AND ABLATION ON LIPID AND FATTY ACID PROFILES OF PENAEUS MONODON EGGS AND EARLY LARVAL STAGES 7.0 Abstract………………………………………………………………….………….121 7.1 Introduction……………………………………………………………….……..….123 7.2 Materials and methods…………………………………………………………..….126 7.2.1 Prawns……………………………………………………………….……126 7.2.2 Egg and larval collection and processing………………………………...126 7.2.3 Biochemical analysis……………………………………………………..127 7.2.4 Statistical analysis…………………………………………………….…..129 7.3 Results………………………………………………………………………………130 7.4 Discussion…………………………………………………………………………..138 8 Chapter 8. REPRODUCTIVE BEHAVIOURAL DIFFERENCES BETWEEN WILD CAUGHT AND POND REARED PENAEUS MONODON PRAWN BROODSTOCK. 8.0 Abstract…………………………………………………………………………….144 8.1 Introduction………………………………………………………………………..145 8.2 Methods……………………………………………………………………………148 8.2.1 Experimental prawns……………………………………………………..148 8.2.2 Holding facilities…………………………………………………………149 8.2.3 Observation tanks……………………………………………………… 149 8.2.4 Observations……………………………………………………………...150 8.2.4.1 Behaviour classification………………………………………………...150 8.2.5 Statistical analysis………………………………………………………...150 8.3 Results………………………………………………………………………………152 8.4 Discussion…………………………………………………………………………..159 Chapter 9. GENERAL DISCUSSION AND CONCLUSIONS…………………………………164 Chapter 10. REFERENCES..............................................................................................................171 PUBLICATIONS……………………………………………………………………...211 9 Chapter 1 INTRODUCTION Prawn farming is now one of the largest aquaculture sectors by volume in Australia after Tuna and Salmon. The main species cultured is the black (or giant) tiger prawn Penaeus monodon which until recently also dominated world prawn aquaculture production (ABARE 2007). The recent decline in production has been dramatic. For example, in 2003 P. monodon accounted for 50% of farmed prawns in Thailand but by 2007 this had dropped to only 5%. While in much of South East Asia it has been replaced by an imported species (P. vannamei), P. monodon continues to demand relatively high market prices and remains the aquaculture species of choice in many countries, including Australia (FAO 2007). Much of the decline in global production of P. monodon can be attributed to disease outbreaks, including viruses originating from the wild-caught spawners. Similar viruses are already limiting the expansion of the Australian industry (Cowley 2005, Lobegeiger and Winfield 2008). Thus the industry reliance, both in Australia and overseas, on broodstock captured from the wild is seen as a major impediment to the continued large- scale production of P. monodon. In Australia there is also evidence that relying on broodstock from the wild has limited industry expansion because of the variability in quality and quantity of its supply (Hansford and Marsden 1995, Marsden et al 1997). For 10 example, in 2000 a major shortage of good-quality wild broodstock severely reduced annual production of this species in Australia (Lobegeiger et al 2005). Proposed solutions to the above problems include the domestication of P. monodon enabling the rearing of successive generations in captivity with known reproductive performance and specific pathogen free (SPF) status.