FAO Fisheries Technical Paper No. 225 FIRI/T225(En) FRESHWATER PRAWN FARMING A MANUAL FOR THE CULTURE OF Macrobrachium rosenbergii by Michael B. New Somsuk Singholka Northcroft and New Chief Chacheongsao Fisheries Station Wroxton Lodge Department of Fisheries Institute Road, Marlow Ministry of Agriculture and Cooperatives Bucks. SL7 1BJ, U.K. Rajdamnern Av., Bangkok 2, Thailand FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome 1982 The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. M-43 ISBN 92-5-101265-2 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy. (1) FAO 1982 PREPARATION OF THIS PAPER This is one of a series of reports periodically produced by the FAO Fishery Resources and Environment Division to help to meet the needs of aquaculture workers of Member Countries for synthesis of information in the field of aquaculture. It was prepared under contract for FAO by the former Co-Managers of the UNDP/FAO Pro- gramme for the Expansion of Freshwater Prawn Farming in Thailand, Messrs. M.B. New and S. Singholka. It reflects mainly the Thai way of freshwater prawn farming, and tries to be as practical as possible, keeping in mind that simple methods are more rapidly applicable in developing countries. It also includes many findings of the UNDP/FAO Programme for the Expansion of Fresh- water Prawn Farming, which have contributed to the advancement of this aquaculture practice in Thailand. Distribution: For bibliographic purposes this docxuaent should be cited as follows: FAO Fisheries Department FAO Regional Fisheries Officers New, M.B. and S. Singholka, Freshwater prawn Regional Projects 1982 farming. A manual for the culture Selector SI of Macrobrachium rosenbergii. GFCM FAO Fish.Tech.Pap., (225):116 p. CIFA CECAF IPFC COPE SCAL Authors - iv - ABSTRACT This manual has been prepared on the basis of Thai experience in the farming of the giant freshwater prawn Macrobrachium rosenbergii. It has a practical orientation, as it was written for extension and fishery officers as well as for practising aquaculturists willing to start freshwater prawn farming. The farming of this prawn is of recent origin, but is spreading very rapidly in several countries which followed the well-divulgated example of Hawaiian prawn farmers. At the time in which this manual was written, Thailand had taken the world leadership in terms of production as the result of an active long-term involvement of both the official and private sectors. Since there is already a great deal of mainly scienti- fic literature on this species, this manual was conceived to fill a gap in the existing literature, in order to pro- vide information on how to go about M. rosenbergii farming answering the numerous requests from Member Governments to FAO. It contains some general information on the biology of the species and much more detailed information on larval rearing and pond culture. The Thai practice forms the core of the manual but reference to other alternative techniques, used elsewhere, is given as well as additional literature references relevent to each topic dealt with in the text, for readers willing to enlarge their knowledge. Annexes on water filtration, nutrition of larvae, des- cription of the various larval stages, pond feeds, seine set design and stock estimation are also provided as well as a glossary of scientific and technical terms used in the main text. - v - CONTENTS Page 1. INTRODUCTION 1 2. BIOLOGY 1 2.1 Distribution 1 2.2 Life History 2 2.3 Morphology 3 3. HATCHERY SITE REQUIREMENTS 4 3.1 Water 4 3.2 Other Requirements 10 4. HATCHERY FACILITIES 10 4.1 The Larval Tank 11 4.2 Holding and Mixing Tanks 14 4.3 Air 14 4.4 Water 14 4.4.1 Supply 14 4.4.2 Treatment 14 4.4.3 Distribution 16 4.4.4 Discharge 16 4.5 Pumps 16 4.6 Monitoring Water Quality 18 4.7 Miscellaneous 18 5. HATCHERY OPERATION 18 5.1 Egg Supply and Hatching 18 5.2 Larval Environment 21 5.2.1 Salinity 21 5.2.2 Temperature 21 5.2.3 Dissolved oxygen 21 5.2.4 General water quality 23 5.2.5 Light 25 5.2.6 Hygiene 25 5.3 Feeding 25 5.4 Growth Rate and Metamorphosis 27 5.5 Harvesting and Holding Post-Larvae 27 5.6 Transporting Post-Larvae 28 5.7 Problems 30 5.7.1 Management 30 5.7.2 Disease and predation 30 5.7.3 Prophylaxis 31 5.8 Alternative Hatchery Techniques 31 5.8.1 High-density culture 31 5.8.2 "Green water" culture 32 5.8.3 Conical tank rearing 32 5.8.4 Recirculation systems 32 5.8.5 Non-coastal hatcheries 33 6. REARING SITE REQUIREMENTS 33 6.1 Market 33 6.2 Water 33 6.3 Power 35 6.4 Topography and Soil 35 - vi - CONTENTS (continued) Page 6.5 Access 37 6.5.1 Market 37 6.5.2 Fry supply 37 6.5.3 Feeds 37 6.6 Sympathetic Authorities 38 6.7 Labour 38 7. FARM FACILITIES 38 7.1 The Pond 38 7.1.1 Shape and size 38 7.1.2 Depth 39 7.1.3 Bunds 39 7.2 Water 39 7.2.1 Supply 39 7.2.2 Treatment 44 7.2.3 Distribution 44 7.2.4 Discharge 44 7.3 Aeration 52 7.4 Miscellaneous 52 8. FARM OPERATION 52 8.1 Pond Management 52 8.2 Stocking 57 8.3 Feeding 57 8.3.1 Feed type 57 8.3.2 Feeding rate 60 8.4 Monitoring 61 8.5 Harvesting 62 8.5.1 Cull harvesting 63 8.5.2 Drain harvesting 65 8.6 Post Harvest 65 8.7 Problems 71 8.7.1 Predations 71 8.7.2 Water quality 71 8.7.3 Weeds 72 8.7.4 Disease 72 8.8 Alternative Rearing Techniques 72 8.8.1 Nursery ponds 73 8.8.2 Cage and pen culture 73 8.8.3 Polyculture 73 8.8.4 Tank culture 73 8.8.5 Open water stocking 74 9. ACKNOWLEDGEMENTS 74 10. REFERENCES 77 Table 1 Typical analysis of fresh water at two successful freshwater prawn hatcheries 81 Table 2 Example of quantity of sea-water needed to make brackish-water for larval culture 81 Table 3 Relationship between temperature, salinity and dissolved oxygen (in ppm) 82 CONTENTS (continued) Page Table 4 Hatchery feeding schedule 82 Table 5 Water requirements for rearing freshwater prawns in ponds 83 Table 6 Average discharge from outlet pipes 83 Appendix 1 Water Filtration 84 Appendix 2 Upward Flow Filtration 95 Appendix 3 Production of Brine Shrimp Nauplii (BSN) Feed for Larvae 97 Appendix 4 Production of Prepared Feed (PF) for Larvae 101 Appendix 5 Key to Larval Stages of Freshwater Prawns Macrobrachium rosenbergii 102 Appendix 6 Stock Estimation 105 Appendix 7 Pond Feeds 107 Appendix 8 Seine Net Design (for "continuous culture" system) 110 Appendix 9 Glossary of Terms and Conversions 111 -1- 1. INTRODUCTION This manual is intended as a practical guide to freshwater prawn farming primarily for extension, rather than research workers. Its contents are a synthesis of the practical ex- perience of its two authors, blended with their observation of the work of others in this field. Although several species of freshwater prawns are currently being cultured, this manual deals exclusively with the farming of the species Macrobrachium rosenbergii, which is in- digenous to South and Southeast Asia, parts of Oceania and some Pacific islands. M. rosenbergii has been imported into many other tropical and subtropical areas of the world and is the species of the genus most favoured for farming purposes. The words, freshwater prawns, when used subsequently in this manual, refer specifically to M. rosenbergii. The hatchery and pond-rearing techniques described are those generally applied to freshwater prawns in Thailand. Only one system of culture has been fully described, to simplify the manual, but reference is made to alternative commercial and experimental tech- niques and many references are provided for further reading. It had originally been intended by the authors to write this manual in an abbreviated 'cookbook' form. However, there is so much art, as well as science, in successful fresh- water prawn farming that this approach did not prove feasible. The manual has therefore been prepared in narrational form. After a brief section on the biology of M. rosenbergii, sections 3-5 deal with hatchery siting, facilities and operation, while sections 6-8 deal with the siting, facilities and operation of ponds for rearing freshwater prawns to market size. Section 10 lists the papers and books referred to in the text. A number of important topics, such as the pre- paration of feed for freshwater prawn larvae, are covered in the Appendixes. A glossary of terms and conversions is given in Appendix 9. The culture of other species of Macrobrachium, though by 1981 still on a limited scale, is taking place using modifications of the techniques described in this manual.