Culture of Rotifer (Brachionus rotundiformis) and brackishwater Cladoceran (Diaphanosoma celebensis) for aquaculture seed production

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1 AQUACULTURE EXTENSION MANUAL NO. 60 JULY 2015 Culture of Rotifer (Brachionus rotundiformis) and brackishwater Cladoceran (Diaphanosoma celebensis) for aquaculture seed production Milagros R. de la Peña Southeast Asian Fisheries Development Center Aquaculture Department Tigbauan, Iloilo

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3 Aquaculture Extension Manual No.60 July 2015 Culture of Rotifer (Brachionus rotundiformis) and brackishwater Cladoceran (Diaphanosoma celebensis) for aquaculture seed production Milagros R. de la Peña Southeast Asian Fisheries Development Center Aquaculture Department Tigbauan, Iloilo

4 ON THE COVER: [Counter-clockwise] Grouper larva; crab megalopa; shrimp mysis [Photos courtesy of Dr. EG Ayson]; Brachionus rotundiformis; 1-ton tank; Nannochlorum; Diaphanosoma with neonates [Photos by MR de la Peña] Culture of Rotifer (Brachionus rotundiformis) and brackishwater Cladoceran (Diaphanosoma celebensis) for aquaculture seed production JULY 2015 ISSN Published and printed by: Southeast Asian Fisheries Development Center Aquaculture Department Tigbauan, Iloilo, Philippines Copyright 2015 Southeast Asian Fisheries Development Center Aquaculture Department Tigbauan, Iloilo, Philippines All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher For comments and inquiries SEAFDEC Aquaculture Department Tigbauan, Iloilo 5021, Philippines Tel Fax AQD website (63-33) (63-33)

5 FOREWORD The intensive larval culture of fish and crustacean larvae requires live food at the onset of exogenous feeding. Their survival during this critical stage depends largely on the reliable and sustained supply of zooplankton. Rotifers are zooplankton most commonly used to feed larval fish and crustacean in hatcheries around the word. They are euryhaline, small, slow swimming, easily digested, and high in nutritional value or can be further nutritionally enriched using supplements (emulsions). Two of the best known strains of rotifer were initially thought to be morphotypes of Brachionus plicatilis, and were referred to as the large (L) and small (S) types. However, it was later established that these are actually two different species with the large being B. plicatilis and the small being B. rotundiformis. This manual deals on the biology and mass culture techniques of the brackishwater small type or B. rotundiformis. Additionally, this publication includes information on the culture of the less used zooplankton, the brackishwater cladoceran (water flea), Diaphanosoma celebensis; and later describes the procedure of the collection of copepods from the wild. Both these zooplankton can be used as complete or partial replacement for the expensive Artemia nauplii. Even as this manual is a product of SEAFDEC/AQD s long and extensive research on zooplankton culture, we will continue to develop and improve the culture techniques of these established zooplankton species. We will also continue to search for new species or local strains of zooplankton, study their biology, and develop the techniques for their mass production. We hope that this manual will be helpful to our stakeholders, especially the operators of hatcheries for marine aquatic species. Likewise, teachers and students of fishery schools would find this manual as a useful source of important information on zooplankton biology and culture. Felix G. Ayson, D.Sc. Chief SEAFDEC Aquaculture Department

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7 TABLE OF CONTENTS Foreword, v INTRODUCTION, p 1 BIOLOGY OF Brachionus rotundiformis, p 2 Habitat, p 2 Gross morphology, life cycle and growth, p 3 Feeds and feeding, p 4 Reproduction, p 5 Nutritional value, p 6 BIOLOGY OF Diaphanosoma celebensis, p 7 Habitat, p 7 Gross morphology, p 7 Feeds and feeding, p 8 Reproduction, p 8 Nutritional value, p 9 CULTIVATION TECHNIQUES, p 9 Culture of green algae, p 9 Culture of Brachionus rotundiformis, p 11 Batch culture, p 12 Semi-continuous or sustenance culture, p 13 Programming culture, p 13 Culture of cladoceran, p 15 REFERENCES, p 19 APPENDICES, p 21 I. Algal counting, p 21 II. Rotifer counting, p 24 III. Preparation of yeast suspension, p 26 IV. Preparation of micronized rice bran, p 27 V. Preparation of cow manure extract, p 28 GLOSSARY, p 30 Acknowledgement, p 31 About the author, p 32

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9 INTRODUCTION Zooplankton are the natural food of the larval stages of many aquaculture commodities. They are the animal component of plankton and are often referred as herbivores or grazers, feeding heavily on phytoplankton. In aquaculture seed production, rotifers and cladocerans are the preferred prey of fish and crustacean larvae due to their suitable size. There is a high chance of success in larval rearing if there is a good correlation of prey size to the gape size of fish larvae. The small-mouth fish like grouper and siganid larvae are fed young rotifers. Being visual feeders, marine fish larvae generally require live food during their early life stages. Rotifers play a significant role in rearing marine fish larvae. Another factor is the slow swimming movement of rotifers and cladocerans that enables the young fish larvae to catch their prey. Rotifers also contain enzymes that help in the digestion of food in the yet undeveloped stomach of the larvae. They are rich in proteins and lipids that are beneficial to fishes. In the larval tank, they also serve as water purifiers since they are filter feeders that consume bacteria and suspended organic matter. The culture of zooplankton is considered as the second order of live food production in aquaculture systems. The success of a multi-species hatchery mainly depends on the continuous availability of live food of high nutritional value. Nutritious zooplankton can be attained through feeding of premium microalgae or through enrichment with high omega 3 emulsions. The larvae that are fed with enriched live food are sturdy and can easily adapt to extreme environmental conditions when transferred to the pond nursery. Rotifers and cladocerans are the two major groups of zooplankton used for fish and crustacean larvae due to their high growth rates and ease of maintenance. The use of cladocerans, Moina sp. and Diaphanosoma sp., are gaining wide acceptance in freshwater fishes and seabass larval rearing, respectively. On the other hand, the use of copepods have shown great potential in fish rearing due to its suitable size and high HUFA (highly unsaturated fatty acids) content. But the mass culture of this zooplankton (mostly Pseudodiaptomus sp and Acartia sp.) has not yet gained wide application in aquaculture due to slow population growth in artificial conditions. They are usually collected from the wild and are directly fed to the fish larvae. To provide a continuous supply of zooplankton food to the growing larvae, understanding their biology and knowledge on mass culture techniques are necessary.