HOME Ecology and Farming of Milkfish Teodora Bagarinao SEAFDEC Aquaculture Department Tigbauan,igbauan, Iloilo,Iloilo, PhilippinesPhilippines October 1999 GO TO : Table of Contents CHAPTER : 1. What is this Fish? 2. Milkfish in Nature 3. The Semilya Fishery 4. Palaisdaan from Bakawan 5. Milkfish in Aquaculture 6. Bangus Production Today 7. The People in the Milkfish Industry 8. Sustainable Milkfish Farming Literature Ecology and Farming of Milkfish Teodora Bagarinao SEAFDEC Aquaculture Department Tigbauan, Iloilo, Philippines October 1999 HOME Bangus or milkfish Chanos chanos (Forsskål), the national fish, is an important part of the diet, economy, ecology, and the science and technology of the Philippines, having been farmed and marketed for about four centuries. This book summarizes the life history and ecology of milkfish and various aspects of the farming industry for the information of all Filipinos. The book celebrates the Centennial of the Philippines on 12 June 1998 and the 25th Anniversary of the SEAFDEC Aquaculture Department and the 5th Anniversary of the AQD Museum on 9 July 1998. T. Bagarinao, e-mail [email protected] Cover painting by Isidro Tendencia: Milkfish harvested from pens in Laguna de Bay. Copyright 1999 by T. Bagarinao. This book or any part of it may not be reproduced without the written permission of the author and the SEAFDEC Aquaculture Department. ISBN 971-8511-36-9 HOME Preface igh hopes are pinned on aquaculture as the solution to the shortfall in the harvests from capture fisheries relative to the expanding human popula- H tion. Such expectations can only be fulfilled by herbivorous or omnivorous farmed species not dependent on fishmeal-based feeds. In the Philippines, Indone- sia, and Taiwan, milkfish has traditionally been grown on natural food (until about a decade ago), and milkfish farming is widely regarded as the way to domestic food security. Thus, large investments were made in the Philippines, Taiwan, Indonesia, and Hawaii in infrastructure, credit, research, and training in support of the milkfish industry. The SEAFDEC Aquaculture Department (AQD), in particular, was established in Iloilo, Philippines in 1973 to develop aquaculture in southeast Asia, and milkfish became one major focus of research. Government agencies and fisheries institu- tions were also fielded in the national effort to intensify milkfish farming starting in the 1970s. Much has been learned about the biology, ecology and aquaculture of milkfish from those years of research and development. Filipino students, teachers, aquafarmers, researchers, extension workers, and policy-makers must know of these advances and understand how milkfish figures in the ecology and economy of the coastal environment that is the Philippines. Such awareness is important as we mark a new millenium with a milkfish industry that is changing in practices, players, dynamics, economic outlook and relevance, environmental impact, and prospects for sustainability. Decisions will have to be made at various levels (the farm, the ecosystem, the country, etc.) and it helps when the general public knows the facts and understands the issues. Although this book is a monograph on milkfish, many similar issues apply to other farmed species. SEAFDEC AQD and Teodora Bagarinao offer this book to the Philippines on the centennial of its nationhood. May there be a thriving milkfish industry during our great grandchildren’s generation and beyond. ROLANDO R. PLATON Chief, SEAFDEC AQD Tigbauan, Iloilo October 1999 iii HOME Acknowledgements ooks are written only by incurring intellectual debt, and I have plenty. Many friends and critics influenced my life and work in milkfish biology over the B past 20 years in more ways than I can thank them for: Jesus Juario, Marietta Duray, Shigeru Kumagai, Yasuhiko Taki, Gunzo Kawamura, Flor Lacanilao, Clarissa Marte, Ronaldo Ferraris, Mila Castaños, Rolando Platon, Renato Agbayani, Jurgenne Primavera, Tetsushi Senta, I-Chiu Liao, Brian Davy, Richard Rosenblatt, and John Hunter. Scientists at SEAFDEC AQD and elsewhere will recognize their work as included in this book; I thank them for their contributions. Clarissa Marte, Marietta Duray, Arnil Emata, and Neila Sumagaysay reviewed parts of the manuscript, but I am responsible for all mistakes that remain. Illustrations are critical to this book: Romeo Buendia provided many recent photographs; Isidro Tendencia, the cover painting; Edgar Ledesma, some drawings; and Shigeru Kumagai, several old photo- graphs. Alberto Purzuelo Jr. of Makinaugalingon Press prepared the lay-out with great technical skill and patience. Friends, family, and my son Carl Emilio made sure that I did not lose my sense of balance through all the computer days and nights. Maraming salamat po sa inyong lahat. Teodora Bagarinao Tigbauan, Iloilo October 1999 iv HOME Table of Contents Preface . iii Acknowledgements . iv Introduction . 1 1. What is this Fish? . 3 The Philippines’ national fish . 3 An international fish . 12 Only one milkfish . 13 2. Milkfish in Nature . 17 Sub-adults (sabalo, lumulukso) . 19 Adults (sabalo) . 21 Eggs and embryos . 29 Larvae . 32 ‘Fry’ and metamorphosis . 36 Juveniles (bangus) . 37 3. The Semilya Fishery . 43 Fry grounds . 43 Fry gears . 45 Fry season . 47 Fry catch . 48 Fry identification . 50 Fry handling . 52 Socioeconomic value . 54 4. Palaisdaan from Bakawan . 57 Conversion of mangroves to fishponds . 57 Biodiversity in the mangroves . 60 Ecosystem goods and services . 63 5. Milkfish in Aquaculture . 67 Broodstocks and spawners . 69 Eggs from broodstock facilities . 72 Larvae in the hatchery . 73 Semilya and fingerlings in nursery ponds . 79 Bangus grow-out in brackishwater ponds . 81 Bangus grow-out in freshwater and marine pens . 93 Bangus grow-out in freshwater and marine cages . 95 The perfect farmed fish . 97 HOME 6. Bangus Production Today . 101 Production and value of bangus . 102 Postharvest handling, processing, marketing . 104 Problems of the industry . 109 Low yields . 109 Decline in production . 111 Environmental degradation . 112 Fry shortage? . 113 Production costs and market constraints . 115 7. The People in the Milkfish Industry . 119 8. Sustainable Milkfish Farming . 125 Aquaculture and the environment: general principles . 128 The milkfish resource system . 130 Understanding the limits . 131 Recommendations for sustainable milkfish farming . 140 Literature . 155 HOME Introduction ish, fishing, and fish farming are very important to the diet, culture, and economy of the people of the Philippines and the rest of Asia. Milkfish F farming in Indonesia, the Philippines, and Taiwan started about 4-6 centuries ago, and milkfish has become a national symbol, the official national fish, of the Philippines. Milkfish figures prominently in the science and technology, and in the economy and ecology of the Philippines. Certainly this is because milkfish is an economic commodity that science and technology is expected to produce more of. Much of the milkfish science and technology and the importance of milkfish to the economy and ecology of the Philippines is described in this book. Perhaps a thousand scientific papers in all have been written about milkfish over the last hundred years. Sunier (1922) described the natural history of marine fishponds in Batavia, Indonesia. Delsman (1926, 1929) collected the eggs and larvae of milkfish for the first time from the Java Sea. In 1929, American ichthyologist Albert Herre and Filipino co-worker Jose Mendoza of the Bureau of Science, Manila, documented milkfish farming in Rizal, Bulacan, Pampanga, Bataan, Iloilo, and Mactan Island. Herre and Mendoza (1929) also included a speculative account of milkfish biology. Hiatt (1944) wrote about milkfish feeding habits in Hawaiian fish ponds, Chen (1952) about milkfish farming in Taiwan, and Tampi (1957,1958) about milkfish in India. All the early literature went into the FAO Fisheries Biology Synopsis on milkfish (Schuster 1960). Papers on milkfish farming and ecology in Taiwan followed (Lin 1968, Lin 1969). Since the 1970s, large investments have been made in the Philippines (as well as in Indonesia, Taiwan, and Hawaii) in terms of infrastructure, credit, research, and training in support of the milkfish industry. The SEAFDEC Aquaculture Department (AQD), in particular, was established in Iloilo, Philippines in 1973 to find solutions to aquaculture problems. Government agencies and fisheries institutions were also fielded in the national effort to intensify milkfish farming. Much has been learned about the biology, ecology, and farming of milkfish during the past 20 years of research and development. Within the past 20 years, SEAFDEC AQD researchers alone have published 166 scientific papers on milkfish and have developed and transferred various technologies in milkfish aquaculture. SEAFDEC AQD itself has published several extension manuals and monographs on milkfish (Kumagai et al. 1980, Smith 1981, Villaluz et al. 1982, Juario and Duray 1982, Juario et al. 1984a, Marte et al. 1984, Bagarinao et al. 1987, Gapasin and Marte 1990, Bagarinao 1991, Emata et al. 1992, FDS 1994, Baliao et al. 1999), some videos, and a poster on the life history. New findings are presented in meetings and taught in training courses at SEAFDEC AQD. HOME Subject matter of publications about milkfish by SEAFDEC AQD researchers. From Bagarinao and Flores (1995a) in part. Number of papers Research topics 1976- 1981- 1985- 1988- 1992- 1995- Total 1980 1984 1987 1991 1994 1997 Broodstock management