AQUACULTURE EXTENSION MANUAL NO. 57 JULY 2014 Intensive culture of milkfish Chanos chanos in polyculture with white shrimp Penaeus indicus or mud crab Scylla serrata in brackishwater earthen ponds Gerry S. Jamerlan, Relicardo M. Coloso, Nelson V. Golez Southeast Asian Fisheries Development Center AQUACULTURE DEPARTMENT www.seafdec.org.ph Aquaculture Extension Manual No.57 July 2014 Intensive culture of milkfish Chanos chanos in polyculture with white shrimp Penaeus indicus or mud crab Scylla serrata in brackishwater earthen ponds Gerry S. Jamerlan Relicardo M. Coloso Nelson V. Golez Southeast Asian Fisheries Development Center AQUACULTURE DEPARTMENT www.seafdec.org.ph Intensive culture of milkfish Chanos chanos in polyculture with white shrimp Penaeus indicus or mud crab Scylla serrata in brackishwater earthen ponds JULY 2014 ISSN 0115-5369 Published and printed by: Southeast Asian Fisheries Development Center Aquaculture Department Tigbauan, Iloilo, Philippines Copyright © 2014 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 SEAFDEC Aquaculture Department and inquiries Tigbauan, Iloilo 5021, Philippines Tel Fax Email AQD website (63-33) 330 7030 / 511 9172 (63-33) 330 7031 / 511 8709 aqdchief@seafdec.org.ph www.seafdec.org.ph FOREWORD Milkfish is an important farmed fish in the Philippines, Taiwan and Indonesia. In the past five years, production in the Philippines has been increasing with brackishwater ponds still contributing the most volume. However, the industry remains confronted with problems such as inadequate fry supply, high cost of farm inputs, limited adoption of commercial-scale value-adding technologies, multi-layered & geographically constrained market distribution system, and limited product promotion for export trade. SEAFDEC Aquaculture Department (AQD) has had 40 years of research and extension devoted to milkfish Chanos chanos. AQD studies on reproduction, larval biology and nutritional requirements of milkfish led to captive breeding and production of high quality fry. Hatcheries now supply most of the fry requirement of the industry which expanded from traditional brackishwater pond culture to pens and cages in freshwater and coastal waters. This manual describes an innovation to milkfish farming: (1) the use of SEAFDECformulated diet and (2) intensive culture of milkfish in polyculture with either white shrimp or mud crab in brackishwater ponds. We hope that fishfarmers and other stakeholders would venture into this business while researchers and students gain knowledge and information from this manual to collaborate with us to further improve the technology. Felix G. Ayson, D. Sc. Chief SEAFDEC Aquaculture Department CONTENTS Foreword Introduction, p 1 Biology, p 2 Source of fry, p 4 Hatchery, p 4 Nursery, p 4 Site selection, p 5 Culture ponds, p 6 Nursery pond, p 6 Transition pond, p 8 Grow-out pond, p 10 Pond management, p 12 Water and soil, p 12 Stocking and acclimation, p 13 Feeds and feeding, p 14 Sampling, p 16 Harvest and post-harvest, p 17 Common diseases, p 20 Parasitic diseases, p 20 Bacterial infection, p 20 Environmental and non-infectious diseases, p 20 Economic analysis, p 22 References, p 27 Acknowledgment, p 28 About the authors, p 29 Biomass in metric tons (x100,000) INTRODUCTION The Philippines, Indonesia and Taiwan consider milkfish as an important food fish with a steadily increasing local demand and fast expanding international market. In the Philippines, milkfish or “bangus” culture is a pioneering and century-old industry and is currently facing new challenges like competing markets with new and novel species in aquaculture and improving growth and production to enable fish farmers to increase profits. Milkfish is reared in freshwater, brackishwater and marine waters. Production by year Figure 1. World aquaculture milkfish production by culture environment (FAO 2011) SEAFDEC/AQD conducted studies that lead to the advancement in milkfish hatchery technology and availability of commercial feeds in the market, which enable fishfarmers to increase their stocking densities in brackishwater ponds and marine cages. AQD has (1) completed the life cycle of milkfish in captivity, (2) developed broodstock technology for milkfish to spawn naturally in captivity; (3) developed techniques for collection of spawned eggs in sea cages as well as in tanks, and (4) developed hatchery rearing technology. AQD continues to improve production, conducting studies on more costefficient and cost-effective formulated diets with lower feed conversion ratio (FCR). Milkfish farmers, on the other hand, have intensified “bangus” farming in brackishwater ponds by stocking 7,000 to 15,000 fry per hectare and using formulated feeds. With feeds, they can “fatten” their stock and/or extend the culture period when there is shortage of natural food. However, the excessive use of feeds may pollute the pond environments and consequently bring about the occurrence of infectious and non-infectious diseases. AQD is therefore recommending the polyculture of bangus and tiger shrimp (sugpo) and/ or mud crab. This will improve the traditional culture of milkfish (stocking density of 1,500 to 2,500 fry per hectare) with farmers also profiting from high-value crops like shrimp and crab. Presently, in extensive milkfish polyculture, milkfish is stocked at 2,000 pieces per hectare, shrimp at 5,000 postlarvae per hectare and mud crab at 500 pieces per hectare. This manual describes the intensive culture of bangus in polyculture with shrimp or mud crab in brackishwater earthen ponds. Figure 2. Milkfish Chanos chanos (Forsskal 1775) BIOLOGY Milkfish Milkfish is the only species in the Family Chanidae in the Order Gonorynchiformes. It is closely related to carps and catfishes. Milkfish, Chanos chanos (Forsskal 1775), is commonly known as bangus, bangos, bangles, bangros, bangilis, banglot and banglis. The FAO species Identification sheets (Fischer and Whitehead, 1974, In Bagarinao, 1991) gave the following description of milkfish. Milkfish body (Figure 2) is elongated, moderately compressed, and without scutes along the belly. The eyes are covered by a fatty outer corneal layer (adipose eyelid). Dorsal and anal fins have basal sheath of scales, large axillary scales are found at the base of pectoral and pelvic fins. Caudal fin is deeply forked. Scales are small, cycloid (smooth) and lateral line is present. Body color in the back is olive-green with silvery sides. The margins of the dorsal and caudal fins are black, and the inside of the pectoral and pelvic fins are dark. Southeast Asia is the center of present-day distribution of milkfish. Milkfish occurs along the coasts of the Philippines, Indonesia, Taiwan, Thailand, Vietnam and Burma. The fish is common throughout the Pacific Islands and can be found in the Indian Ocean and across the Pacific Ocean, tending to school around coasts and islands with reefs. It apparently stays relatively close to islands and coasts of continents. Distribution is limited to waters with temperatures greater than 20°C. The fish spawn naturally in clear oceanic waters, usually less than 40 m in depth over sand or coral, about 30 km offshore during the warm months of the year. The pelagic eggs (1.1-1.2 mm in diameter) and larvae (3.5 mm at hatching) are essentially planktonic for two weeks and the distribution depends on water movements. The larvae then migrate onshore and are caught by fine-mesh nets operated along sandy beaches and mangrove areas. The fry (10-17 mm long) live at sea for 2-3 weeks and then migrate 2 Polyculture of milkfish and white shrimp or mud crab in ponds Photo from Quinitio 2003 to mangrove swamps, estuaries, and sometimes in lakes. Then the fish return to the sea to mature sexually and reproduce. Juveniles and adults in the wild live in mangrove areas, coastal lagoons, and even go upriver into lakes. They eat a wide variety of relatively soft and small food items, from microbial mats to detritus, epiphytes, zooplankton, and feeds. The adults are pelagic, schooling, migratory, and large-sized, growing up to 1.5 m in length and 20 kg in weight. Milkfish matures sexually in 5 years with a body weight of 3 kg or more. It is a popular fish for culture because it tolerates a wide range of salinity, temperature and water quality. It adapts well to high-density, and reaches marketable size in 4-7 months. Figure 3. Mud crab Scylla serrata Figure 4. White shrimp, Penaeus indicus Mud crab or mangrove crab The mud crab or mangrove crab Scylla serrata (Figure 3) is a species belonging to Family Portunidae under the Order Decapoda, Class Crustacea and Phylum Arthropoda. This crab is commonly known as the giant or king crab, alimango, kinis, banhawan and bulik. The color of the carapace is green to black. Mud crabs have separate sexes. Immature females have a triangular-shaped abdomen or abdomenal flap while mature females have broader, semi-circular abdomen. Males have T-shaped abdomen. Mature males have bigger chelipeds than the female of the same carapace size. Crabs dig and inhabit burrows in mangroves and soft-bottom intertidal water, hence, they are called mud crab or mangrove crab. Courtship and mating occur in brackishwater. White shrimp The white shrimp Penaeus indicus (Figure 4) is commonly known as hipon puti (Tagalog); pasayan, putian (Ilonggo); and lunhan (Cebuano). It belongs to Genus Penaeus, Family Penaeidae under Class Crustacea. Ground body color is yellowish white, speckled with dark green; uropod is greenish at proximal and yellowish green at distal portions fringed with red and creamy hairs. Pleopods are white and with brownish red mottles. This species is commercially caught in brackishwater and open sea up to 30 m in depth. SEAFDEC Aquaculture Department 3 SOURCE OF FRY Hatchery Stocking of ponds in traditional milkfish aquaculture relies on fry collected from the wild. This has led to a wide range of variability in fry quality and quantity between seasons and regions. To improve culture, AQD developed technologies on captive breeding and mass fry production. These technologies are already adopted by fish farmers in the Philippines. A lot of bangus breeding and hatchery facilities were developed nationwide to minimize fry importation and supply the needs of the expanding bangus industry. Eggs are hatched, raised, and then sold at ages of 21 days or older. Natural food (Chlorella, Brachionus) are fed to the larvae. Rotifer is particularly enriched with highly unsaturated fatty acids (HUFA) and Vitamin C. SEAFDEC-formulated larval feed is given in combination with natural food from day 8 until harvest. Today, supply of hatchery-reared bangus fry is no longer a problem. Similarly, the breeding and hatchery technologies for shrimp and mud crab are welldeveloped. Shrimp fry and crablets are available year-round and farmers no longer depend on wild catch. Nursery Another source of bangus is from the nursery. Shallow brackishwater earthen ponds with an area of 500-2,000 m2 and 30-40 cm water depth is the rearing area for bangus fry to become juveniles. These pond nurseries have lablab or benthic algae as natural food. The fry is reared for 15-20 days prior to transfer or selling. Formulated diets for fry can be given to supplement the natural food and boost fish growth. Figure 5. Milkfish hatchery 4 Polyculture of milkfish and white shrimp or mud crab in ponds SITE SELECTION In selecting a site for milkfish culture, choose one that has: • enough brackishwater supply year-round. The parameters normally considered for a suitable water supply are shown below: Parameters pH Dissolved oxygen (ppm) Salinity (ppt) Temperature (0C) Ammonia nitrogen (ppm) Hydrogen sulfide (ppm) Alkalinity (ppm) Transparency (cm) Range 7.5 - 8.5 4.0 - 9.0 10 - 30 26 - 32 less than 1 less than 0.3 less than 10 10 - 50 • moderate tidal fluctuation of 2-3 m. This will enable the pond to be completely drained during low tide and to admit water during spring tide • clayey soil to ensure that the pond can hold water. The soil must also be suitable for growing natural food such as lablab or lumut. Avoid areas with acid sulphate soils • access to good quality fingerlings for stocking. Proximity to market and urban centers should also be considered so fish farmers can lessen the overhead cost and avoid delay in transporting or hauling stocks, supplies & materials • reliable supply of electricity • security and without social problems (like poaching) Existing brackishwater fishponds or tiger shrimp farms can also be utilized for intensive milkfish farming. But it might be necessary to: (1) Improve or modify existing pond structures to suit the management requirements of intensive milkfish culture, make water management and stock manipulation easier, and meet desired production targets (2) Construct three different compartments ~ nursery ponds (NP), transition ponds (TP) and feeding ponds (FP) (see next section). Ideally, these ponds must have: • sizes that are manageable enough for feeding; 0.8 to 1.2 ha is ideal. Transition ponds should be larger than the feeding ponds for optimum production using the modular method • shapes that are rectangular or square with separate water inlet and outlet gates for easier and efficient water exchange, circulation and harvest • water depth of 1-1.5 m with the bottom leveled off for easy harvest SEAFDEC Aquaculture Department 5 CULTURE PONDS In the past, brackishwater ponds for milkfish followed a general design and construction which was developed through long years of experience. Fishpond engineering has now emerged from the traditional into a more advanced method today. Machines have shortened construction time and decreased labor and cost. Milkfish farms are classified according to three types of operation: (1) nursery system where the farmer raises fry to fingerlings and sells the fingerlings to other milkfish farmers; (2) rearing pond system where fingerlings are stocked and reared until these are market-sized; and (3) combination nursery-rearing pond where the farmer grows fry to market-size. The third type is the most common today with farms having nursery, transition and grow-out ponds. Milkfish may be grown in two types of system: (1) monoculture and (2) polyculture. In monoculture, a single species (milkfish) is produced in the farm. Monoculture can be extensive, semi-intensive or intensive. In intensive culture, stocking density ranges 1-2 per m2 or 10,000-20,000 fish per ha. In polyculture, two to three species are stocked together. These species usually have different feed preferences and habits or niches. Mud crab and shrimp can be cultured with milkfish, as described in this manual. Milkfish stocking density is 1 fish per m2 or 10,000 fish per hectare. Nursery pond The pond area suited for nursery operation is from 500 to 2,000 m2 (Figure 6). Before the development of bangus feeds, nursery rearing in brackishwater ponds was primarily dependent on natural food. The main concern is to establish, propagate, and sustain the natural food in the pond until the desired fish size can be harvested. Continuous research brought advances in feeds and feeding, and availability of commercial feeds gave way to high stocking densities since milkfish no longer depend entirely on natural food. To achieve quality milkfish juveniles and high survival in the nursery, ensure that: (1) competitors and predators are properly eradicated (2) organic and/or inorganic fertilizer is applied to encourage the growth of natural food (3) good water quality favorable to the stock and its natural food is maintained The two types of natural food base commonly grown in brackishwater nursery ponds are lablab and lumot (Figure 7). Lablab is the preferred natural food in the nursery. Lablab. This consists of minute plants and animals which form a yellowish green to dark green mat on the pond bottom. Lablab is currently used by most fish farmers because it is more nutritious and digestible compared to lumot. Lablab is grown by 6 Polyculture of milkfish and white shrimp or mud crab in ponds Figure 6. Earthen nursery ponds using a combination of organic and inorganic fertilizers. Organic fertilizers are used and broadcasted evenly in the pond bottom at a rate of 2 tons per ha. Application is done once a year or during summer time. Inorganic fertilizers (16-20-0 and 46-0-0 in combination) are broadcasted at a ratio of 1:2 bags per ha. B-net screen (one foot in width) can be used and positioned or hanged across the pond bottom to increase the attachment area for fish food organisms. This increases the carrying capacity of the nursery pond. Lumot or filamentous algae. This consists primarily of filamentous green algae such as Enteromorpha sp. and Chaetomorpha sp. Lumot is grown by planting or by broadcasting, and it is fertilized with 16-20-0 at a rate of 100 to 150 kg per ha. The fertilizer is subdivided into a weekly dosage with the water changed or admitted prior to fertilizer application. In the nursery pond, lumot is not a good natural food for the fry so 46-0-0 or urea is broadcasted at a rate of 50 to 100 kg per ha on top of the algae to soften it and promote growth of lablab. Once the algae is softened, bangus fry can be stocked. AB Figure 7. Natural food for milkfish in ponds: (a) lablab and (b) lumot SEAFDEC Aquaculture Department 7 Proper nursery pond preparation is crucial prior to stocking. To do this: (1) Level the pond bottom and have this slope towards the drain gate for easy transfer (2) Dry the pond for 10-15 days (3) Eradicate predators and competitors immediately using tea seed powder at 10-15 ppm or one part ammonium sulfate [(NH4)2SO4] mixed with five parts hydrated lime [Ca(OH)2 or CaO] dissolved in water. Splash the mixture evenly into the pond bottom where stagnant water and puddles are situated (4) Install fine mesh screens in the gates to control the intrusion of predators and competitors (5) Apply organic fertilizer (chicken manure or mud press) at a rate of 2 tons per ha during the drying period of 2-3 weeks. Organic fertilization is usually applied once a year during the peak of summer (6) Admit water to a depth of about 10 cm to start growing natural food and increase gradually as the lablab or lumot develops and grows (7) Broadcast inorganic fertilizer periodically with 5-7 days interval using 46-0-0 and 16-20-0 at a ratio of 1:2 to 1:3 bags per ha. An initial dose of 50 kg per ha is broadcasted and followed by fertilizer dressing of 20-25 kg applied weekly in the next 30-45 days (8) Change 20-30% of pond water prior to fertilizer application (9) Maintain water depth of 40-60 cm. Water replenishment is done during spring tides to ensure high survival and quality juveniles. After stocking, minimize water replacement to leave natural food undisturbed Stock fry in the early morning or late afternoon (when the temperature is cool) at a density of 30-50 fry per m2. Acclimate the fry first to salinity and temperature in the nursery pond. Culture period is 15-20 days or until the fry reach ¾ inch to 1 inch in length. Bangus fry feed can be used to supplement the natural food to boost fish growth. Transition pond Transition pond is the next pond used after nurturing the bangus fry (Figure 8). The area ranges from 0.5 to 2 ha which is stocked with 2-3 milkfish fingerlings per m2 (Figure 9). Transition ponds are also called stunting ponds or holding-stock ponds. This is where the yearly fingerling requirement is held so the farmer can have a continuous grow-out pond operation. Pond preparation is usually done simultaneously for the nursery pond and feeding pond. Two to three compartments of the same pond size is recommended as transition ponds. Bangus juveniles are reared in this pond for 30-45 days or until the natural food is totally depleted, after which, a bangus feed for juveniles is broadcasted 2-3 times daily to extend the rearing period up to 60 days. Another option after natural food depletion is to transfer the stock to another prepared transition pond to reduce feed cost. The target body weight for transfer is 20-40 g, though bigger size fingerlings are better to stock. Pond preparation of transition ponds follows the same protocol as for nursery ponds. 8 Polyculture of milkfish and white shrimp or mud crab in ponds Figure 8. Transition pond with lablab (left) and lumot AB CD Figure 9. (A) Newly stocked fingerlings at the transition pond, (B) transfer of stock using a drain net after 60 days of culture, (C) counting of fingerlings for stocking at the grow-out / feeding pond, and (D) stocking of fish in the pond SEAFDEC Aquaculture Department 9 Grow-out pond The size of grow-out / feeding pond for milkfish is 0.8 to 1.2 ha with recommended stocking density of 1 per m2 or 10,000 per ha. During the growing of the natural food (pond preparation), mud crab (Scylla serrata; 300 pieces per ha, 1 cm carapace width) or white shrimp (Penaeus indicus or P. vannamei; 20,000 per ha, PL 15-20) can be stocked ahead of bangus. The polyculture species to be stocked depends on the kind of pond bottom and the size of bangus to be transferred. Mud crab or shrimp is stocked one month before milkfish is transferred to the grow-out pond. For hard pond bottoms and bigger fish fingerlings, white shrimp is a much better species. Culture period of milkfish stocked at 60 g is 75-90 days; at this time shrimp can be harvested. On the other hand, mud crab like soft pond bottoms for burrowing, and the culture period is much longer (120 days or more). Many commercial farms in the Philippines now stock between 1.0 and 4.0 fish per m2 depending on the intensity of the production system. The transformation from extensive to intensive systems has been achieved with the increasing use of fertilizers and feed, and provision of extra life support systems such as aerators and pumps. Bangus stocked extensively can normally thrive on natural food and achieve good growth and survival. Intensive bangus culture also make use of natural food in the pond prior to full feeding using formulated diets. Fish growth and survival in this kind of culture method is dependent on formulated feeds. Pond preparation of grow-out ponds follows similar protocol as nursery or transition ponds with the following additions: (1) Install a depth gauge near the gate to monitor water depth. A feeding catwalk is constructed at the middle of the pond as a letter “T” and made out of bamboo (Figure 10). (2) Till or plow the pond bottom and apply lime once a year (Figure 11-A). Tilling is done to allow mineralization and release of nutrients from the soil. This reduces the build-up of any harmful organic waste (3) Apply agricultural lime and hydrated lime at a rate of 2 tons per ha and 1 ton per ha, respectively. A much longer drying should be done. In the grow-out pond, feed is given after the natural food is totally depleted. Sample the average body weight of the fish before feeding (initial weight) for feed computation. Culture period ranges from 75 to 120 days depending on the initial weight of fish at stocking and targeted body weight at harvest. 10 Polyculture of milkfish and white shrimp or mud crab in ponds Figure 10. Grow-out pond with the feeding catwalk A B CD Figure 11. Grow-out pond preparation: (A) tilling and liming done once a year; (B) installation of bamboo enclosure and screen net in gates; (C) application of inorganic fertilizer to grow natural food; and (D) feeding of stock with commercial feed SEAFDEC Aquaculture Department 11 POND MANAGEMENT Water and soil In nursery and transition ponds, culture period is short, thus water exchange is minimal or is done only when the need arises (ie. heavy rainfall or die-off of natural food as indicated by milky white coloration of the water). Inorganic fertilizer is used as dressing at low doses (5-10 kg per ha) in 5-7 day intervals to maintain the growth of natural food. In ponds with low organic matter (>5%) in the soil, organic fertilization is recommended. Replenish water regularly after the natural food is totally depleted in the feeding pond. This is done to maintain favorable water quality (Table 1) and to avoid occurrence of fish disease and mortality. Also, when the fish biomass reaches 800 kg, use paddlewheel aerators in the feeding pond to increase dissolved oxygen levels, decrease ammonia in the water and support the increasing fish biomass until harvest. The aerators are usually operated at night when dissolved oxygen levels become low. Use submersible pump to maintain a minimum pond water depth and desired water quality. A pump is also useful during emergencies or at neap tide when water exchange is needed. After 90 days of culture in grow-out ponds, apply agricultural lime at a rate of 150 to 200 kg per ha every two weeks to help retain the quality of pond soil. Organic fertilizer is not recommended. Table 1. Percentage and frequency of water exchange in intensive bangus culture Pond Nursery Transition Grow-out Water depth 30-40 cm 40-60 cm 80-120 cm Culture period (days) 15-20 1-15 15-30 30-45 45-60 1-30 30-60 60-90 90-120 Percent water drain none or as the need arises none or as the need arises 20-30% 30-40% 30-40% 20-30% 30-40% 40-50% 40-50% Interval every 15 days every 15 days every 15 days every 15 days every 15 days weekly weekly Frequency once 2 consecutive days 2 consecutive days 2 consecutive days 2-3 consecutive days 2 consecutive days 2-3 consecutive days 12 Polyculture of milkfish and white shrimp or mud crab in ponds Photo courtesy of R RAGUS A B C Figure 12. Milkfish (A) and shrimp (B) fry are acclimated to salinity and temperature prior to their release in the nursery pond; and (C) crablets at stocking Stocking and acclimation The fingerling must be acclimated to the salinity and temperature prevailing in the pond during stocking to prevent mortalities (Figure 12). This is vital to milkfish growth and survival. Temperature and salinity differences must not exceed 50C and 5 ppt, respectively. Acclimation is done by slowly adding pond water to the plastic bags or basin where the fish is held during transport. When the water is swirled in the basin, the normal movement of healthy bangus fingerlings is to swim against the current. Lighter body coloration is also a sign that the fingerlings are ready for release. Handle fingerlings with care. Mud crabs are hardy but they can die from inappropriate handling or exposure to extreme conditions. Acclimation is also necessary since a sudden change in environmental condition can weaken crabs. Acclimate crab and shrimp, too. SEAFDEC Aquaculture Department 13 Feeds and feeding When the natural food in the grow-out pond is consumed, bangus pellet feeds (Table 2) is used for the remaining culture period. Feeding is started when natural food is used up. Milkfish accept a variety of feeds such as sinking or floating pellets. Stock sampling is done to obtain the initial average body weight (ABW) of fish for feed computation. In the grow-out pond, a daily feed allowance (DFA) is given at a sliding rate of 6 to 2% of the biomass. Adjust the DFA every 15 days and broadcast the feed 3-5 times daily (Table 3). It is recommended to use floating pellets produced by the extrusion process. Figure 13. Feeding catwalk design and proper feed direction Crabs or shrimps can thrive on available natural food and excess feeds from bangus that settle at the pond bottom. Prior to feeding, the fish should be attracted by sound (such as tapping a bamboo pole) to induce them to come to the feeding area. Feeding time should be fixed. Introduce small amounts of feed into the water while tapping to gather the fish in front of the feeding area. Bangus are very adaptable to both floater and sinker feeds since they are pelagic and are bottom feeders. To limit overfeeding, it is recommended to use floater feeds. Broadcast the feed in both sides of the feeding bridge while walking from one end to the other (Figure 13). This will increase Figure 14. Feeding the milkfish the feeding area and avoid or minimize size differences during harvest. In one hectare pond area, feeding catwalk should be 50-60 feet or two full lengths of bamboo; the bridge from the dike should also have the same length. Hand feeding has been found ideal for ponds. Demand feeders and automatic feed spreaders are now used in semi-intensive and intensive pond culture operations. Growth of bangus fed SEAFDEC formulated diet is shown in Figure 14. Proximate analysis of harvested milkfish is shown in Table 4. 14 Polyculture of milkfish and white shrimp or mud crab in ponds Table 2. Proximate analysis of SEAFDEC formulated diet for bangus (Coloso RM, unpublished) Feed type Starter crumble / pellet Grower pellet Finisher pellet Moisture 5.48 4.30 5.52 Crude protein 31.63 28.26 27.00 Percent of dry matter Crude fat Crude fiber 5.75 2.86 4.83 5.41 6.16 5.38 Ash 6.20 7.57 6.45 Nitrogenfree extract 53.56 53.93 55.02 Table 3. Feeding ration for milkfish at a given size Size Pond* Feed ration Feed type Frequency in a day Fry to 1 in NP 10% Fry mash 2 to 3 1-3 in NP2 / TP1 8% Juvenile crumble 2 to 3 20-50 g TP2 7% Starter crumble 3 50-150 g TP3 / FP 6% Starter pellet 3 to 5 150- 200 g FP 5% Grower pellet 5 200-300 g FP Grower/ 4% finisher pellet 5 > 300 g FP 3-2% Finisher pellet 5 * NP, nursery pond;TP, transition pond; FP, feeding or grow-out pond 8 am - 30% 30% 10% 10% 10% Feeding time 10 am 12 nn 2 pm 50% - - 50% - - - 35% - - 35% - 15% 20% 25% 15% 20% 25% 15% 20% 25% 4 pm 50% 50% 35% 35% 30% 30% 30% Table 4. Proximate analysis of newly-harvested bangus fed SEAFDEC formulated diet Moisture (%) Ash (%) Crude protein (%) Crude fat (8%) Crude fiber (%) Nitrogen-free extract (%) 71.48 8.85 65.94 22.51 0.46 2.24 SEAFDEC Aquaculture Department 15 Average body weight, g Days of culture Figure 15. Growth of bangus fed SEAFDEC formulated diet. The verification study was done at AQD’s Dumangas Brackishwater Station in Iloilo Sampling Periodic sampling of milkfish is done every 15 days to monitor weight, size and health (Figure 15). It is the basis for the computation of the daily feed requirement. During sampling, use seine nets to randomly collect 100-300 samples to compute for the average body weight. Then weigh the fish in groups of 10-15 pieces, compute the total weight, and divide by the number of groups to derive the average body weight of the samples. Feed adjustment is done after sampling. No sampling is done for the crabs or shrimps since they are considered as secondary species / commodity. 16 Polyculture of milkfish and white shrimp or mud crab in ponds HARVEST AND POST-HARVEST In the Philippines, farmers usually use special catching ponds during total harvest. This method takes advantage of the tendency of milkfish to swim against the current. This is done by partially draining the grow-out pond during low tide and then allowing water into the pond at high tide. Fish swim into the catching pond at the gate, and when most are inside, close the gate and use a seine to gather fish. The small number of fish that will remain as well as mud crab or shrimp can be hand-picked after the pond is totally drained. See Figure 16. Bangus can be partially harvested by seining to catch fish weighing 400 g or any size preferred by the market or by the buyer. Shrimp survival is about 50% with ABW of 17 g and mud crab survival is about 30% with ABW of 300 g. Immediately after harvest, the fish are killed by chilling them in iced water (5-6 blocks ice per ton of fish). This is done to preserve the freshness and quality. Milkfish are then packed in plastic crates topped with crushed ice for transport to the fish port. Milkfish processing takes two forms. Traditional ways include smoking, drying and fermenting. Modern techniques include bottling, canning and freezing. A steady increase in demand for deboned milkfish in the market has been observed, furthermore there is an increasing trend toward value-added products. A B Figure 16. (A) Seining to collect sample every 15 days; (B) bulk weighing to get the average body weight of fish SEAFDEC Aquaculture Department 17 A B CD Figure 17. (A) Seining the fish during partial harvest; (B) gathering and scooping the fish for chilling; (C) submerging the fish into a chilling tank with ice; (D) sorting for market; (E) packing the fish for the market; (F) transport to market; (G) handpicking shrimp after the pond is totally drained; (H) total draining to harvest crab 18 Polyculture of milkfish and white shrimp or mud crab in ponds EF G H SEAFDEC Aquaculture Department 19 COMMON DISEASES Diseases are more frequent in cultured animals than in natural populations. In captivity, fish compete with each other for space, feed, and dissolved oxygen. Fish pathogens are often present in the water but healthy fish can normally resist those present in culture systems. Stress reduces the resistance of fish to infections caused by these organisms. Milkfish is a sturdy fish and hence ideal for mass production. However, with the advent of intensified culture technique, unavoidable occurrences of infectious and noninfectious diseases attributed to biotic and abiotic factors could arise. Parasitic diseases Severe parasitic infestation in milkfish causes heavy mortality from the fry up to the adult stage. Parasitic diseases cause skin irritation and damage, tail rot, loss of scales and mucus, respiratory difficulties, anemia, skin ulcers, jaw deformation, swollen muscles, and distended abdomens. Affected fish usually rub their body against an object, reduce food intake and opercular movement, exhibit discolored body surface, retarded growth, and mortality. In the presence of infectious microbial organisms, parasitic infestation can trigger secondary bacterial infection. See Table 6 for the common parasitic diseases of milkfish. Bacterial infection Bacteria are present almost everywhere in the aquatic environment. Most of bacterial disease agents are part of the normal microflora. Bacteria are generally considered as secondary or opportunistic pathogens, causing severe mortality in hatchery and grow-out due to poor water quality and management, improper handling of fish and overfeeding. Infected fish exhibit signs of weakness, abnormal swimming behavior and loss of appetite. See Table 7 for the common bacterial diseases of milkfish. Environmental and non-infectious diseases Non-infectious diseases of fish can be ascribed to several factors including adverse environmental conditions, nutritional disorders, genetic defects and poor aquaculture practice and management. Attributes such as low dissolved oxygen, high ammonia and nitrite level, and introduction of man-made toxins into aquatic environments may cause catastrophic mass mortalities to fish but they are not contagious in nature. See Table 9 for common environmental and non-infectious diseases of milkfish. 20 Polyculture of milkfish and white shrimp or mud crab in ponds Table 6. Common parasitic diseases of milkfish (Cruz-Lacierda et al, 2011) Disease agent Parasites Protozoans Digeneans Acanthocephalans Caligus Amyloodinium ocellatum, Trypanosoma spp. Pseudometadena spp., Lecithochirium spp., Transversotrema spp., Prosorhynchus spp., Bucephalus spp., Stellantchasmus spp., Procerobum spp., Hemiurus spp., Gonapodasmius epinepheli, Gauhatiana spp. Acanthocephalus spp., Pallisentis spp. Caligus epidemicus, Caligus patulus Lernaid Lernaea sp. Isopod Marine leech Alitropus Zeylanicobdella arugamensis Table 7. Common bacterial infections of milkfish (Alapide-Tendencia & de la Peña 2001) Disease agent Pathogenic bacteria Bacteria Vibrio parahaemolyticus, Aeromonas hydrophila, Pseudomonas spp., Mycobacterium spp. Table 8. Common environmental and non-infectious diseases of milkfish (Erazo-Pagador 2001) Disease ssociated with physicochemical parameters Causes Gas bubble Supersaturated oxygen in the water Swim bladder stress syndrome Improper handling, high temperature, high illumination and pollutants Asphyxiation / hypoxia Very low dissolved oxygen in the water Salinity stress Abrupt changes of salinity; above or below salinity tolerance of fish Alkalosis High pH or water is too basic Acidosis Low pH or water is acidic Sunburn High water temperature due to shallow and clear water Other physical defects Undeveloped operculum Nutrient deficiencies and mechanical stress to eggs and larvae SEAFDEC Aquaculture Department 21 ECONOMIC ANALYSIS Cost-and-return analysis was done on a verification study on the intensive culture of milkfish fed with SEAFDEC-formulated diets conducted at AQD’s Dumangas Brackishwater Station. Milkfish market price was observed to be relatively lower from April to August. Meanwhile, prices are generally higher and stable throughout the rest of the year. Hence, milkfish farming can be more profitable when harvest coincide with the period when market prices are high and if bigger fish were harvested. For the past decades, intensive culture of milkfish has been shown to be economically viable industry in the Southeast Asian region. However, with the increasing cost of inputs, especially feeds, and the competing uses of pond areas for other culture species and other productive activities, milkfish growers have started reporting declining profitability from milkfish farming. A comparative cost-benefit analysis of milkfish monoculture and polyculture, either with highvalue shrimp or mud crab, is shown in Table 9 to demonstrate options for improving profitability of milkfish farming. The analysis was based on an actual grow-out culture in a 0.83 hectare feeding pond stocked with 15,000 milkfish fry in SEAFDEC/AQD fishpond facilities. Fifty-five percent of these fry survived the nursery phase. Hence, 8,300 fingerlings were fed and grown to a target marketable size of 400 g in 120 days of culture, with 90% survival rate. During the nursery stage, feeding depended on lablab, while formulated diet was used in feeding during the grow-out phase. The feed conversion ratio was 1.5 during this grow-out phase. The investments in facilities and equipment are basically similar for monoculture and polyculture systems. The production costs are likewise almost similar, except for the cost of the shrimp fry (Php 5,000 at 25 cents per piece) and crablets (Php 1,245 at Php 5 per piece) in the polyculture system. The amount and cost of milkfish feeds amounting to Php 147,906 per crop are similar for all three production systems. The cost of feeds accounts for about 60% of the total production cost. The benefit from polyculture systems that apply similar feeding rates as monoculture systems manifest in higher total biomass harvest. Yield was highest for milkfish and shrimp polyculture (3,129 kg), followed by milkfish and mud crab polyculture (3,018 kg) and lowest for milkfish monoculture (2,988 kg). At Php 85/kg selling price of milkfish, Php 200/kg shrimp and Php 280/kg mud crab, the polyculture of milkfish and shrimp was most profitable with Php 61,785 net income per year with two crops per year; 118% return on investment (ROI); and less than one year (0.79) pay-back period. The polyculture of milkfish and mud crab was moderately profitable with Php 29,587 annual net income and 56% ROI. The monoculture of milkfish resulted to only Php 15,345 net income per year and 29% ROI. With a six-year project duration, the intensive milkfish polyculture with shrimp is expected to show the highest discounted benefit-cost ratio (BCR) at 4.32 at 12% discount rate and 104% internal rate of return (IRR). Meanwhile, the polyculture of milkfish with crab show 1.80 discounted BCR and 38% IRR. Finally, the intensive monoculture of milkfish is expected to generate only Php 0.68 per unit peso investment. Therefore, given the increasing cost of intensive milkfish farming, polyculture with high-value species such as shrimp and mud crab without introducing additional feeds and other inputs is recommended. 22 Polyculture of milkfish and white shrimp or mud crab in ponds Table 9. Comparative economic analysis of intensive milkfish monoculture and polyculture A. Technical assumptions Milkfish monoculture Milkfish and shrimp polyculture Milkfish Shrimp Milkfish and mud crab polyculture Milkfish Mud crab Project duration, years Nursery pond, hectare Transition pond, hectare Grow-out or feeding pond, hectare Number of crops/year Days of culture/crop Initial size at stocking Fry stocked in nursery pond (pieces) Survival rate of milkfish, nursery phase (%) Stocking density in feeding pond (pieces/hectare) Juveniles stocked in feeding pond (pieces) Survival rate (%) Number of fish harvested per crop Feed coversion ratio of milkfish Harvest weight (g) Production per crop (kg/crop) Production per year (kg/yr) Farmgate price (Php/kg) Gross value of harvest per crop (Php) * CW - carapace width 6 0.1 0.5 .83 2 120 50 g 15,000 6 0.1 0.5 0.83 2 120 50 g PL 20 6 0.1 0.5 0.83 2 120 50 1 cm CW* 15,000 15,000 55 55 55 10,000 10,000 20,000 10,000 300 8,300 90 7,470 1.5 400 2,988 5,976 85 253,980 8,300 90 7,470 1.5 400 2,988 5,976 85 253,980 16,600 8,300 50 8,300 17 141 282 200 90 7,470 1.5 400 2,988 5,976 85 28,220 253,980 249 40 100 300 30 60 280 8,366 B. Cost of investments on facilities and equipment and depreciation (similar for the 3 types of production system) Equipment and materials Quantity Investment Cost Lifespan Annual depreciation cost (Php/year) Reinvestments Year 3 and 5 Paddle wheel aerators (1-2 HP) 2 units 50,000 6 8,333 Bamboo poles for footwalk 1,200 2 600 1,200 Nets 0.3 roll 1,050 2 525 1,050 Monofilament #160 1 kg 250 2 125 250 Total 52,500 9,583 2,500 C. Operating cost per crop I. VARIABLE COST Pest and predator eradication Hydrated lime Ammonium sulfate Pond preparation Agricultural lime Organic fertilizer Urea 16-20-0 Rearing Milkfish fry, Php 0.25/pc Shrimp fry, Php 0.25/pc Crablets, Php 5/pc Milkfish feeds Power and fuel cost Harvest expenses Total variable cost II. FIXED COST Wages, 1 farm aide, Php 6,000/month full-time Technician/supervisor fees P4,000/month part-time Pond rent, P10,000/ha/year Interest on capital, 12% per year Depreciation Total Fixed cost TOTAL PRODUCTION COST PER CROP Quantity Milkfish monoculture Milkfish and shrimp polyculture Cost (Php) Milkfish and mud crab polyculture 50 kg 10 kg 95 95 95 160 160 160 1,050 kg 1,200 kg 1.5 bag 4 bags 1,470 1,440 1,500 4,000 1,470 1,440 1,500 4,000 1,470 1,440 1,500 4,000 15,000 pcs 20,000 pcs 249 pcs 4,482 kg 3,750 147,906 12,000 2,500 174,821 3,750 5,000 147,906 12,000 2,500 179,821 3,750 1,245 147,906 12,000 2,500 176,066 36,000 24,000 5,000 3,150 4,792 72,942 247,763 36,000 24,000 5,000 3,150 4,792 72,942 252,763 36,000 24,000 5,000 3,150 4,792 72,942 249,008 24 Polyculture of milkfish and white shrimp or mud crab in ponds D. Gross income per crop Milkfish monoculture Total biomass harvest (kg/crop) Bangus Shrimp Mud crab Total gross value of harvest Bangus, Php 85/kg Shrimp, Php 200/kg Mud crab, Php 280/kg Average gross return per kg biomass produced (Php/kg biomass) 2,988 2,988 253,980 253,980 85 Milkfish and shrimp polyculture 3,129 2,988 141 282,200 253,980 28,220 Milkfish and mud crab polyculture 3,018 2,988 30 262,346 253,980 8,366 90 87 E. Economic efficiency indicators Income per crop (Php) Income per year (Php) Return on investment (ROI, %) Payback period (years) Break-even production (kg total biomass) Break-even price per kg biomass produced (Php) Milkfish monoculture 6,217 15,345 29 2.61 2,915 82.92 Milkfish and shrimp polyculture 29,437 61,785 118 0.79 2,803 80.78 Milkfish and mud crab polyculture 13,339 29,587 56 1.53 2,864 82.51 F. Financial investment analysis A. Milkfish monoculture Year 0 Year 1 Gross revenue 507,960 Investment costs 52,500 Total cost 498,435 Net Income (52,500) 9,525 Net present value (12%) (46,875) 7,593 Internal rate of return Discounted benefitcost ratio Year 2 507,960 498,435 9,525 6,779 Year 3 507,960 2,500 498,435 7,025 4,464 Year 4 507,960 498,435 9,525 5,405 Year 5 Year 6 Total 507,960 2,500 498,435 7,025 507,960 498,435 9,525 3,047,760 57,500 2,990,612 (352) 3,559 4,308 (14,766) 0% 0.68 SEAFDEC Aquaculture Department 25 cont. Table F B. Milkfish and shrimp polyculture Year 0 Year 1 Year 2 Gross revenue 564,400 564,400 Investment costs 52,500 Total cost 508,435 508,435 Net Income (52,500) 55,965 55,965 Net present value (12%) (46,875) 44,615 39,835 Internal rate of return Discounted benefitcost ratio C. Milkfish and mud crab polyculture Gross revenue 524,693 524,693 Investment costs 52,500 Total cost 500,925 500,925 Net Income (52,500) 23,767 23,767 Net present value (12%) (46,875) 18,947 16,917 Internal rate of return Discounted benefitcost ratio Year 3 Year 4 Year 5 Year 6 Total 564,400 2,500 508,435 53,465 564,400 508,435 55,965 564,400 2,500 508,435 53,465 564,400 508,435 55,965 3,386,400 57,500 3,050,612 278,288 33,978 31,756 27,087 25,316 155,710 104% 4.32 524,693 2,500 500,925 21,267 524,693 500,925 23,767 524,693 2,500 500,925 21,267 524,693 500,925 23,767 3,148,157 57,500 3,005,552 85,105 13,516 13,486 10,775 10,751 37,518 38% 1.80 26 Polyculture of milkfish and white shrimp or mud crab in ponds REFERENCES Alapide-Tendencia EV, de la Peña LD. 2001. Bacterial diseases. In: Lio-Po GD, Lavilla CR, CruzLacierda ER (eds). Health Management in Aquaculture. Aquaculture Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines. p 25-42 Bagarinao TU. 1991. Biology of Milkfish (Chanos chanos Forsskal), Iloilo, Philippines: Aquaculture Department, Southeast Asian Development Center Bagarinao T, Kumagai S. 1987. Occurrence and distribution of milkfish, Chanos chanos off the western coast of Panay Island, Philippines.Environmental Biology of Fishes, 19: 155-160 Baliao DD. 1982. Management of brackishwater pond for milkfish fingerling production in Sri Lanka. Inland Fish. Sri Lanka, 1:17-29 Baliao DD. 1984. Milkfish Nursery Pond and Pen Culture in the Indo-Pacific Region, p 97-119 Baliao DD. 1983. Mudcrab, Alimango, Production in Brackishwater Pond with Milkfish. In:APDEM (VI : 1983 : Tigbauan, Iloilo) Papers . Tigbauan, Iloilo : SEAFDEC Aquaculture Department. 3:(8 p.) Baliao DD, de los Santos M, Franco NM. 1999.The modular method: milkfish pond culture. Tigbauan, Iloilo: SEAFDEC/ADQ. Aquaculture Extension Manual No.25. 18 p Coloso RM, Benitez LV, Tiro LB. 1988. The effect of dietary protein-energy levels on growth and metabolism of milkfish (Chanos chanos Forsskal). Comp. Biochem. Physiol. (A Comp. Physiol) 89A (1):11-17 ICLARM R90-216 Cruz-Lacierda ER, Erazo-Pagador GE, Yamamoto A, Nagasawa K. 2011. Parasitic caligid copepods of farmed marine fishes in the Philippines. In: Bondad-Reantaso MG, Jones JB, Corsin F, Aoki T (eds). Diseases in Asian Aquaculture VII. Selangor, Malaysia: Fish Health Section, Asian Fisheries Society. p 53-62 Cruz-Lacierda ER, Maeno Y, Pineda JT, MateyVE. 2004. Mass mortality of hatchery-reared milkfish (Chanos chanos) and mangrove red snapper (Lutjanus argentimaculatus) caused by Amyloodium ocellatum (Dianoflagellidae). Aquaculture, 236:85-94 Cruz-Lacierda ER, Erazo-Pagador GE. 2001. Physical, environmental, and chemical methods of disease prevention and control. Aquaculture Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines de la Cruz CR. 1979. A brief of milkfish pond engineering. Technical Consultation on Available Aquaculture Technology in the Philippines. SEAFDEC-PCARR Workshop,Tigbauan, Iloilo, Philippines DurezaVA. 1977. Production responses of milkfish Chanos chanos (Forsskal) in brackishwater ponds to additional substrate for fishfood organisms. PCARR Fisheries Research Forum, Manila Erazo-Pagador GE. 2001. Environmental and other non-infectious diseases. In: Lio-Po GD, Lavilla CR, Cruz-Lacierda ER (eds). Health Management in Aquaculture. Aquaculture Department, Southeast Asian Fisheries Development Center, Tigbauan, Iloilo, Philippines. p 75-82 Jamandre TJ, Rabanal HR. 1975. Engineering aspects of brackishwater aquaculture in South China Sea Region. South China Sea Fisheries Development Programme. Manila Keenan CP, Davie PJP, Mann. 1998. A revision of the genus Scylla de Haan, 1833 (Crustacea:Decapoda:Brachyura: Portunidae). Raffles Bulletin of Zoology 46:217- 245 Landau M. 1992. Introduction to Aquaculture. J. Wiley & Sons, USA. 440 p Lee CS. 1995. Aquaculture of milkfish (Chanos chanos). Tungkang Marine Laboratory, Taiwan and The Oceanic Institute, Hawaii, USA. Aquaculture Series No. 1. 141 p Lijauco MM, Juario JV, Baliao DD, Griño E, Quinitio G. 1979. Milkfish culture and management. Extension Manual No. 4. Southeast Asian Fisheries Development Center Aquaculture Department. Tigbauan, Iloilo, Philippines LinYM, Chen CN, Lee TH. 2003. The expression of gill Na, K-ATPase in milkfish,(Chanos chanos) acclimated to seawater, brackishwater and freshwater. Comparative Biochemistry and Physiology Part A, 135: 489-497 Lio-Po G, Lim LHS. 2002. Infectious diseases of warm water fish in fresh water, In: Diseases and Disorders of Finfish in Cage Culture, Woo PTK, DW Bruno, LHS Lim, Cabi Publishing. New York, USA, 231-81 SEAFDEC Aquaculture Department 27 Luckstadt C, Focken U, Coloso RM, Becker K. 2000. Survey on the use of natural food and supplemental feed in commercial milkfish farms in Panay, Philippines. International Agricultural Research- A Contribution to Crisis Prevention, Book of Abstracts, Hohenheim, Germany. p 229-230 Motoh H, Buri P. 1984. Studies on the penaeid prawns on the Philippines. Researches on Crustacean. 13-14:1-120 p Nelson JS. 1994. Fishes of the world. 3rd edition. J Wiley & Sons, USA. 600 p Pillay T.V.R. and Kutty M. N.(2005). Aquaculture: Principles and Practices. 2nd Edition. Blackwell, USA. 624 p Quinitio ET, Parado-Estepa FD. 2003 and 2008. Biology and Hatchery of Mud crabs Scylla spp. SEAFDEC Aquaculture Extension Manual No. 34, Iloilo, Philippines. 39 p Sumagaysay-Chavoso NS, Mc Glore MLSD. 2003. Water quality and holding capacity of intensive and semi-intensive milkfish (Chanos chanos) ponds. Aquaculture 219:413-429 Sumagaysay NS, Borlongan IG.1994. Growth and reproduction of milkfish (Chanos chanos) in brackishwater ponds: effect of dietary protein and feeding levels. Aquaculture132: 273-283 Sumagaysay NS.1998. Milkfish (Chanos chanos) production and water quality in brackishwater ponds at different levels and frequencies. Journal of Applied Ichthyology 14: 81-85 Seng LT, Colorni A. 2002. Infectious diseases of warm water fish in marine and brackish water In: Diseases and Disorders of Finfish in Cage Culture, Woo PTK, DW Bruno, LHS Lim, Cabi Publishing. New York, USA, p 193-230 Tacon A. 1998. The nutrition and feeding of farmed fish and shrimp, Training Manual 3. Feeding Methods, FAG Field document, Project GCP/RLA/ 075/ Field document 7/E, FAQ, Brasilia, Brazil. 208 p Tucker WJ.1998. Marine Fish Culture 1st edition, Kluwer, Harbor Branch Oceanographic Institution and Florida Institute of Technology, Melbourne, FL, USA.750 p Villegas CT, Bombeo I.1981. Effects of increased stocking density and supplemental feeding on the production of milkfish fingerlings. Quarterly Research Report. Southeast Asian Fisheries Development Center Aquaculture Department, Tigbauan, Iloilo, Philippines ACKNOWLEDGMENT The authors thank Jerry Babiera, Alfredo Sotela, Efren Gonzales, Ricaredo Gabayeran and Dominador Leabres for their technical support. We also thank Gwen Anuevo and Margarita Arnaiz of the AQD Laboratory for Advanced Aquaculture Technologies for the analysis of fish and feeds, Gerald Gonzaga and the staff of AQD Pilot Feed Mill for the feed production. We also thank DBS for the ponds used for our feed verification study, Dr. Maria Rowena Eguia, Dr. Joebert Toledo and AQD for the financial support of the bangus project and the AQD’s publication review committee Dr. Relicardo Coloso. Dr. Evelyn Grace Ayson, Dr. Rolando Pakingking, Dr. Maria Rowena Eguia, Dr. Maria Lourdes Aralar, and Dr. Nerissa Salayo for the final review of the manual. A special thanks to iMarine Aquaculture for the collaboration under the ABOT AquaNegosyo Project, which demonstrated the feasibility, economic viability of milkfish polyculture with shrimp. 28 Polyculture of milkfish and white shrimp or mud crab in ponds ABOUT THE AUTHORS Mr. Gerry S. Jamerlan joined SEAFDEC Aquaculture Department in February 2007 as Senior Technical Assistant. He conducted and assisted various verification and demonstration projects on marine and brackishwater fish. He also authored a manual on Intensive culture of sea bass in brackishwater earthen ponds. He obtained his B.S. degree in Inland Fisheries at the University of the Philippines Visayas in 1982. He acquired his extensive experience in fishpond culture and management of brackishwater fishes from his work experiences as technical consultant from various private sectors in Iloilo, Capiz, Aklan, Quezon, Batangas, and Mindoro since 1988. He also worked as a senior aquaculturist at Vitarich Corporation (1984-1986), as aquaculture technologist at the Continental Grain Company (1996-1999) and as department production manager at Pond Operations PT. Wachyuni Mandira at Sumatra, Indonesia (1999-2004). Recently, he worked as DOST CAPE consultant for Region VI in 2012. At present, he manages farms in Cebu, Davao and Sorsogon. Dr. Relicardo M. Coloso is a Scientist at the Nutrition and Feed Development Section and former head of SEAFDEC/AQD’s Research Division. He obtained his Ph.D. in Nutritional Sciences from Cornell University as a Fullbright-Hays Mutual Educational Exchange Grantee. He finished his MS degree in Biochemistry at the University of the Philippines Diliman on a PCMARD-SEAFDEC scholarship and his BS Chemistry degree (cum laude) also at UP Diliman as an NSDB (now DOST) scholar. He obtained his secondary education as a science scholar at the Philippine Science High School. He was postdoctoral fellow at the Department of Pharmacology and Physiology, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, and later a postdoctoral associate at the Division of Nutritional Sciences, Cornell University. He was also a fellow in fish nutrition at the Institute of Marine Biochemistry, Aberdeen, Scotland. He has been senior lecturer in biochemistry at the University of the Philippines Visayas and presently at the College of Medicine, Central Philippine University. His areas of specialization are on fish nutrition, biochemistry, amino acid and phosphorous metabolism, nutrition of milkfish, tiger shrimp, Asian seabass, grouper, molluscicides, and environmental contamination and toxicology. He was a recipient of a research grant from the International Foundation for Science (IFS) in 1991. He also conducted studies on molluscicides for snail pests in brackishwater ponds with a research grant from Lonza, Inc. Presently, he conducts studies on the use of soy products as alternatives to fish in milkfish feed with research grant from the United Soybean Board. He has authored and co-authored more than 35 scientific papers published in international journals and proceedings. He has served as a reviewer for Aquaculture, Aquaculture Nutrition, and the UPV Journal of Natural Sciences, among others. He co-authored the text book on nutrition in tropical aquaculture which was awarded the 2004 Outstanding Book Award by the National Academy of Science and Technology. He was also a Gawad Lagablab outstanding alumni awardee from the Philippine Science High School Alumni Foundation. SEAFDEC Aquaculture Department 29 Mr. Nelson V. Golez is a visiting researcher at SEAFDEC/AQD. He was also the Feed Mill Supervisor of Feed Development Section in 1998. He holds a BS degree in Chemical Engineering from Adamson University, Manila, Philippines, and then went to Kyoto University, Kyoto, Japan for his MS in Soil Chemistry as a Monbusho Scholar in 1988. His areas of specialization varies from fish nutrition and feed development, water quality and soil chemistry, pond culture, feed milling, feed processing, and storage. He is a member of the Philippine Institute of Chemical Engineers, the Pollution Control Association of the Philippines-Region VI chapter, and the Philippine Association of Japanese Monbusho Exchange Scholars. He was a recipient of the Dr. Elvira O. Tan Award for best published research paper in Aquaculture in 1998. He is the author and co-author of several papers published in refereed international journals. ABOUT SEAFDEC The Southeast Asian Fisheries Development Center (SEAFDEC) is a regional treaty organization established in December 1967 to promote fisheries development in the region. The member countries are Brunei Darussalam, Cambodia, Indonesia, Japan, Lao PDR, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam. The policy-making body of SEAFDEC is the Council of Directors, made up of representatives of the member countries. SEAFDEC has four departments that focus on different aspects of fisheries development: • The Training Department (TD) in Samut Prakan, Thailand (1967) for training in marine capture fisheries • The Marine Fisheries Research Department (MFRD) in Singapore (1967) for post-harvest technologies • The Aquaculture Department (AQD) in Tigbauan, Iloilo, Philippines (1973) for aquaculture research and development, and • The Marine Fishery Resources Development and Management Department (MFRDMD) in Kuala Terengganu, Malaysia (1992) for the development and management of fishery resources in the exclusive economic zones of SEAFDEC member countries. AQD is mandated to: • Conduct scientific research to generate aquaculture technologies appropriate for Southeast Asia • Develop managerial, technical and skilled manpower for the aquaculture sector • Produce, disseminate and exchange aquaculture information AQD maintains four stations: the Tigbauan Main Station and Dumangas Brackishwater Station in Iloilo province; the Igang Marine Station in Guimaras province; and the Binangonan Freshwater Station in Rizal province. AQD also has an office in Quezon City. www.seafdec.org.ph