Aquaculture Extension Manual No. 40 July 2008 Breeding and seed production of the Asian catfish Clarias macrocephalus (Gunther) Josefa D. Tan-Fermin, Armando C. Fermin, Ruby F. Bombeo, Ma. Antonietta D. Evangelista, Mae R. Catacutan, Corazon B. Santiago Southeast Asian Fisheries Development Center AQUACULTURE DEPARTMENT www.seafdec.org.ph Aquaculture Extension Manual No. 40 July 2008 Breeding and seed production of the Asian catfish Clarias macrocephalus (Gunther) Josefa D. Tan-Fermin, Armando C. Fermin, Ruby F. Bombeo, Ma. Antonietta D. Evangelista, Mae R. Catacutan, Corazon B. Santiago Southeast Asian Fisheries Development Center AQUAwCwUwLT.sUeaRfEdeDcE.oPArgR.pThMENT Breeding and seed production of the Asian catfish Clarias macrocephalus (Gunther) July 2008 ISBN 978-971-8511-86-2 Published and printed by: Aquaculture Department Southeast Asian Fisheries Development Center Tigbauan, Iloilo, Philippines Copyright © 2008 Aquaculture Department Southeast Asian Fisheries Development Center 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: Tel Fax Email AQD website SEAFDEC Aquaculture Department Tigbauan, Iloilo 5021, Philippines (63-33) 511 9172 (63-33) 511 8709 aqdchief@seafdec.org.ph bookstore@seafdec.org.ph http://www.seafdec.org.ph FOREWORD Catfish is one of the most important freshwater food fishes in Southeast Asia. In recognition of its importance, AQD has been conducting researches to further improve technologies on broodstock and nursery development, grow-out techniques, and the development of feed formulations for catfish from the nursery to grow-out phase. This manual was published to disseminate science-based aquaculture technologies developed by AQD to assist catfish nursery and hatchery growers in producing high-quality fingerlings. We also hope that researchers in the field of fisheries, students and teachers could benefit from the information on the breeding and seed production of this important aquaculture commodity. Let us continue working together for the development of the fisheries industry. Joebert D. Toledo, D. Agr. Chief SEAFDEC/AQD CONTENTS Foreword iii Introduction 1 Broodstock development and management 2 Source 2 Transport 2 Preparation of tank or pond 3 Feeding 3 Breeding 4 Stocking 4 Hormone preparation 5 Injection or hormone administration 7 Sacrifice of males 8 Stripping of females 9 Artificial fertilization 9 Incubation of eggs 10 Hatchery 11 Larval stages: Day 0 11 Day 1-2 11 Day 3 11 Day 4-6 11 Day 7-10 12 Day 11-14 12 Culture of natural food organisms 13 Nursery 14 Pond 14 Tank 15 Lake 16 Health management 16 Profitability of catfish broodstock and hatchery operations 18 References and other catfish papers by SEAFDEC/AQD 21, 23 About the authors 23 Acknowledgment 25 INTRODUCTION Catfishes are widely distributed in many countries in Asia, Africa, Europe as well as Central, South and North America. Some species form a significant part of inland fisheries, several have been cultured, and many species are of interest to the aquarium industry. Except for Families Ariidae (Arius manilensis or “kanduli”) and Plotosidae that have marine species, catfishes generally inhabit freshwater environments. Species cultured as food fish primarily belong to Families Ictaluridae (channel catfish), Siluridae (European catfish), Pangasidae (Pangasius from Vietnam) and Clariidae (Asian catfishes), which contributed more than 1.6 million metric tons to global catfish production in 2005. Most catfishes in the Philippines are under the Family Clariidae. They have elongated bodies with long dorsal (usually without spines) and anal fins, and four pairs of barbels or “beards” located near the mouth. Barbels are highly sensitive taste organs used by catfishes in search for food. The pectoral fins have strong spines. Catfishes also have suprabranchial organs which enable them to use atmospheric air. With their pectoral spines and suprabranchial organs, catfishes can leave water and walk on land for several hundred meters. The most studied and of great importance in fisheries and aquaculture among clariid catfishes are the Asian catfishes Clarias macrocephalus and C. batrachus, and the African catfish C. gariepinus. Figure 1. The Asian catfish Clarias macrocephalus Before the early seventies, the native catfish C. macrocephalus was abundantly found in rice fields and other natural habitats in the Philippines. Introduction of a related, faster-growing species from Thailand, C. batrachus, briefly promoted the culture of catfish in the 1970s, but was hampered by lack of cost-effective spawning agents, lack of seed supply, and lack of cost-effective diets. The African catfish was introduced to the Philippines in the late 1980s. It is a much bigger fish than the native and Thai catfish, which are almost similar in size and appearance. The native catfish can be distinguished from the Thai catfish by the shape of the occipital process (the center of the head portion when the fish is viewed dorsally), blunt or rounded in 2 Breeding and seed production of the Asian catfish Figure 2. Asian catfish species C. macrocephalus C. batrachus the former and pointed in the latter, and presence of white spots along the sides of the body in C. macrocephalus. C. gariepinus also has a pointed occipital process. Of the three Clarias species, C. macrocephalus is preferred because of its tender and delicious meat. It is also resistant to diseases, can be stocked at higher densities, and has low requirements for water quality. C. macrocephalus is sometimes crossbred with the African catfish to get better-tasting and bigger-sized fish. This kind of hybrid forms the bulk of catfish production in Thailand. This manual summarizes the techniques developed at SEAFDEC/AQD on the breeding and seed production of the native catfish. BROODSTOCK DEVELOPMENT AND MANAGEMENT FACTORS TO CONSIDER Source ■■ ■■ Can be obtained from lakes, rivers, tributaries and other freshwater bodies Are caught by hand or indigenous fish traps Transport ■■ Can be transported in any container made of styrofoam, plastic, metal and the like ■■ Container can be filled with pond or river water just enough to cover the catfish ■■ Aeration is not needed since catfish can breathe atmospheric oxygen SEAFDEC Aquaculture Department 3 Figure 3. Earthen pond and concrete tanks for maintaining catfish broodstock Preparation of tank or pond ■■ Broodstock can be stocked at 10-15 pieces/m2 in earthen ponds or in concrete tanks lined with mud at the bottom (Fig. 3) ■■ Ponds are maintained at 70-100 cm water level Feeding ■■ Catfish are carnivores. They feed naturally on insects, shrimps, worms and organic detritus, but easily accept artificial feeds ■■ SEAFDEC has formulated a broodstock diet that can replace trash fish when fed at 3% of the body weight Table 1. Composition (%) of SEAFDEC broodstock diet for catfish* Ingredient Fish meal Defatted soybean meal Meat and bone meal** Copra meal Cornstarch Soybean oil Vitamin mix*** Ricebran Total Composition (%) 15 35 22.4 3.44 2 3 3.55 15.61 100 *Estimated nutrient content (dry matter basis) : crude protein 35-37%, crude fat 9-10%, crude fiber 4-5%, crude ash 14-15%, and nitrogen-free extract or digestible carbohydrate 30-32% **Not available in the market. Substitute the level with other ingredients available in the area. A suggestion is a 1:1:1 ratio of cracked corn, snail meal and crab meal (or dried trash fish) ***Commercially available BREEDING At 3-4 months, sexes can be distinguished externally by the presence of elongated, urogenital papillae in the males, and a round opening in the females at the lower, ventral side of the body (Fig. 4a). Age determines maturation in catfish. When fed properly, catfish mature in about 6-8 months. The reproductive organ consists of a pair of ovaries with unfertilized eggs in the females, and a pair of testis found at the anteriormost region, followed posteriorly by a pair of seminal vesicles with about ten fingerlike projections in the males (Fig. 4b). Figure 4. (a) distinguishing features of male and female catfish (b) catfish reproductive organs (b) Ovary (a) Male Female Testis-seminal vesicles The natural breeding season in catfish varies from place to place, but usually starts during the rainy season. Although catfish contain unfertilized eggs year-round upon reaching maturity, these are not released spontaneously when catfish are held under captive conditions. This is because gonadotropin is not released, although it reaches a high level when the fish attains sexual maturity. Gonadotropin is a hormone produced in the pituitary gland that affects reproduction in fishes. The different hormones used are meant to facilitate the release (luteinizing-hormone releasing hormone or LHRH) or increase (human chorionic gonadotropin or HCG, pituitary gland extract or homogenates) gonadotropin levels in the body of the fish. LHRH is used alone or in combination with dopamine antagonists, e.g., pimozide (PIM) or domperidone (DOM). Dopamine is found in the brain, which inhibits the release of gonadotropin from the pituitary glands. Catfish are best induced to spawn using hormones starting in May, the start of the rainy season in the Philippines. January to April is not a good time to induce catfish to spawn because females have relatively fewer eggs and males have fewer sperm inside their bodies. For induced spawning, choose bigger females since fecundity increases with size, and bigger males with whitish urogenital papillae to get a greater amount of milt. SEAFDEC Aquaculture Department 5 Follow these procedures in inducing catfish to spawn: DAY 1 - 6:00-7:00 AM Fish stocking • Drain the tank or pond in the early morning and get at least 20 males and 50 females • Place males and females in separate holding containers • Cover the tanks with nets Figure 5. Holding containers for male and female catfish broodstock prior to induced spawning work Hormone preparation • Hormones to be injected should be ready before 3 PM • Use either one of these methods: pituitary gland extracts, HCG, LHRHa + PIM or DOM, Ovaprim, or Ovatide (Table 2) Table 2. Methods used in the induced spawning of C. macrocephalus Inject females with A : 1 pituitary gland (homogenized)/100 g BW B : 4 I.U. of human chorionic gonadotropin (HCG)/g BW C : 0.05 µg luteinizing hormone-releasing hormone analogue (LHRHa) + 1 µg pimozide (PIM)/g BW D : 0.5 µL Ovaprim /g BW E : 0.2 -0.5 µL Ovatide/g BW strip after 13 -14 h 13 -18 h 16 -20 h 16 -20 h 16 -20 h • Determine or approximate the total body weight of female catfish to be injected METHOD A : For pituitary gland extracts Get pituitary glands from sexually mature fish Add 1 mL of physiological saline or 0.9% NaCl (dissolve 0.9 g NaCl in distilled water to reach final volume of 100 mL solution) Macerate using a small vortex mixer, and get the extracts using a glass syringe 6 Breeding and seed production of the Asian catfish METHOD B : For HCG Dose of HCG : 4 I.U./g body weight (BW) Injection volume : 1 µL /g BW 0.08 mL A 100-g female (100 g x 4 I.U./g) will receive 400 I.U. or 0.08 mL of HCG Concentration of HCG available : 5000 I.U./1 mL (HCG solution) 400 I.U. : volume of HCG solution needed = 5000 I.U. : 1 mL volume of HCG solution = 400 / 5000 volume of HCG solution = 0.08 mL or 80 µL Prepare human chorionic gonadotropin (HCG) by dissolving 1 vial containing 5000 I.U. HCG in 1 mL physiological saline or 0.9% sodium chloride (dissolve 0.9 g NaCl in distilled water to reach final volume of 100 mL solution) METHOD C1 : For LHRHa + PIM For LHRHa Dose of LHRHa : 0.05 µg/g body weight (BW) Injection volume : 1 µL/g Total body weight of females to be injected, e.g. (100 g x 2 fish) x 2¤ = 400 g Total amount of LHRHa needed : 400 g x 0.05 µg/g = 20 µg Total volume of LHRHa needed : 400 g x 1 µL/g = 400 µL Concentration of LHRHa needed : 20 µg / 400 µL = 0.05 µg / µL Concentration of LHRHa available per ampule or vial : 250 µg 0.05 µg : 1 µL = 250 µg : volume of liquid (0.9% NaCl) to dissolve LHRHa volume of liquid = 250 µL/0.05 volume of liquid = 5000 µL or 5 mL To prepare LHRHa , dissolve LHRHa (250 µg) in 5 mL physiological saline or 0.9% sodium chloride A 100-g female 100 g x 1 µL/g) will receive 100 µL or 0.10 mL of LHRH ¤Allowance for spillage SEAFDEC Aquaculture Department 7 METHOD C2 : For PIM Dose of PIM : 1 µg/g body weight (BW) Injection volume : 1 µL/g Total body weight of females to be injected, e.g. (100 g x 2 fish) x 2¤ = 400 g Total amount of PIM needed : 400 g x 1 µg/g = 400 µg Total volume of PIM needed : 400 g x 1 µL/g = 400 µL *Two solvents (dimethylsulfoxide or DMSO, and propylene glycol or PG) are used to dissolve PIM at 1:9 400 µL/10 parts (1 part DMSO + 9 parts PG) = 40 µL/1 part (DMSO) 40 µL/1 part x 9 parts (or 400 µL - 40 µL) = 360 µL (PG) 1 Weigh 400 µg of PIM and place in a test tube 2 Add 40 µL of DMSO and dissolve the PIM using the vortex mixer 3 Add 360 µL of PG to the solution and mix well with the vortex mixer A 100-g female (100 g x 1 µL/g) will receive 100 µL or 0.10 mL of PIM ¤Allowance for spillage • Ovaprim and Ovatide are commercial preparations containing LHRHa and domperidone. These are in liquid forms and ready for use, after knowing the body weight of the female catfish METHOD D : For Ovaprim Dose of Ovaprim : 0.5 µL/g body weight (BW) Injection volume : 1 µL/g BW A 100-g female (100 g x 0.5 µL/g x 1 µL/g) will receive 50 µL or 0.05 mL of Ovaprim METHOD E : For Ovatide Dose of Ovatide : 0.2 µL/g body weight (BW) Injection volume : 1 µL/g BW A 100-g female (100 g x 0.2 µL/g x 1 µL/g) will receive 20 µL or 0.02 mL of Ovatide 8 Breeding and seed production of the Asian catfish Injection or hormone administration Figure 6. Injection of hormones • Place 5 mL of the anaesthesia (2-phenoxyethanol) in a pail containing 10 liters of tap water and mix well • Place several females at one time into the pail and remove individually the fish that are less actively swimming around with a scoop net • Briefly pat dry the fish with a towel • Get and record the body weight of the fish • Wipe the site to be injected with a cotton moistened with rubbing alcohol • Inject each fish on the dorsal musculature using a disposable tuberculin syringe at 1 µL per g body weight • Put all injected fish in one tank or container and place a net cover DAY 2 – STARTING AT 8 AM OR 16-20 HOURS AFTER INJECTION • Try exerting gentle pressure on the lower abdomen of the hormoneinjected females while inside the tank • If eggs easily ooze out from most females, males can be sacrificed Sacrifice of males • Place 5 mL of the anaesthesia (2-phenoxyethanol) in a pail containing 10 liters of tap water and mix well • Place several males at one time into the pail and remove individually the fish that are less actively swimming around • Briefly pat dry the fish with a towel • Place each male in the ventral position, and cut up the middle part of the body using a scalpel or scissors • Dissect a pair of testes-seminal vesicles located on both sides of the body and place in a Petri dish Figure 7. To obtain milt or hydrated suspension of sperm: (a) sacrifice male and dissect the reproductive organ (with asterisks); (b) remove and macerate the testis-seminal vesicles in a Petri dish; (c) add saline solution to the macerated reproductive organ ** (a) (b) (c) SEAFDEC Aquaculture Department 9 • Add 0.9% NaCl or physiological saline into the Petri dish and remove excess blood from the organ with the scapel • Briefly blot dry the organ with tissue paper and transfer to a clean Petri dish • Macerate the organ and add 0.6% NaCl (get 67 mL of physiological saline solution and add 33 mL of distilled water) to obtain milt solution • Transfer the milt solution in a small beaker • Milt from two males can be pooled together Stripping of females • Anaesthetize each gravid female Figure 8. Stripping of female catfish • Dry the body especially the lower ventral abdomen with a towel • Press the abdomen of the female to strip eggs into a clean, dry bowl or basin • Several females can be stripped simultaneously or one after the other, and their eggs combined in the bowl or basin • Eggs from 4-5 females can be pooled in the same basin or bowl Artificial fertilization • Pour the milt solution into the bowl or basin containing the stripped eggs and mix for 30 to 60 seconds using a feather • Add approximately 5 mL of tap water to the bowl and mix further to ensure fertilization • Transfer fertilized eggs to a scoop net and wash with running tap water for about a minute to remove excess milt • Spread the eggs on a monolayer on the net tray inside a flow-through hatching trough Figure 9. Artificial fertilization (left to right): mixing the eggs and sperm using a feather; transferring the fertilized eggs to a scoop net and washing with running tap water; spreading the eggs on a monolayer in a flow-through hatching trough 10 Breeding and seed production of the Asian catfish Figure 10. Incubation of eggs in containers made of (a) marine plywood or (b) plastic basin (a) (b) NOTE: Speed is important in doing the above procedures since sperm are motile for only a few minutes, stripped eggs are viable for about 1-2 minutes, and closure of the micropyle (the opening on the egg through which sperm enter to fertilize the egg) occurs within a few seconds Incubation of eggs • Use rectangular containers made of marine plywood or plastic basin to incubate eggs (Fig. 10) • Place fertilized eggs on a framed screen net tray (Fig. 11) suspended on a slanting position inside the incubation container • Have a flow-through, recirculating water supply during incubation until hatching of the larvae, which is about 24-30 hours when the water temperature is 26-30oC • Supply freshwater by gravity flow from elevated reservoirs and maintain at a water level of about 10 cm inside the trough. A standpipe may be placed at the opposite end of the water inlet • Use rain water during incubation to get high fertilization and hatching rates of the eggs Figure 11. Screen net tray to be placed inside the hatching trough HATCHERY DAY 0 LARVAE • Observe if most larvae have hatched 24-30 hours after fertilization and incubation • Slowly move the framed screen net tray to drop the newly hatched larvae into the bottom of the trough, leaving only the dead eggs and unhatched larvae on it • Newly hatched (day 0) larvae measure 4-4.5 mm • Larvae can be maintained in a static system • Start the culture of Moina (see separate section on p. 13) DAY 1-2 LARVAE • Larvae wriggle vigorously • Healthy larvae start to group together at the corners, while larvae that are scattered eventually die (Fig. 12) • Clean the hatching troughs by siphoning off dead eggs or larvae, mucus and other foreign bodies at the tank bottom • Change 30% of the water in the trough • Maintain larvae in a static system Figure 12. Healthy (left) and unhealthy (right) catfish larvae DAY 3 LARVAE • Follow the same procedures in maintaining Day 1-2 larvae • Hatch Artemia cysts (see separate section on p. 13) DAY 4-6 LARVAE Larvae are actively swimming, and yolk is now almost resorbed. The mouth of the larvae is functional and the barbels are longer. Size of larvae ranges from 7 to 8 mm, and larvae weigh about 3 mg each. 12 Breeding and seed production of the Asian catfish Larvae are transferred to bigger tanks, fed with Artemia (see separate section on p. 13), and maintained under the following conditions: • Reduce the amount of water in the incubation trough • Place the trough with the larvae inside a bigger tank for about 15 minutes for acclimation • Pour larvae from the trough into the tank • Siphon dead eggs, larvae or excess feed daily at the tank bottom before replenishing the rearing water and feeding the larvae • Keep the water level at 10-15 cm in depth to allow the larvae to gulp air at the water surface • Provide mild aeration to ensure oxygen supply to the larvae • Place substrates of old nylon nets made into ribbon strips tied to sinkers at the bottom of the tanks to serve as resting places for the larvae after feeding • Place shelters for smaller larvae to minimize being eaten by the larger larvae • Change about 30% of the water in the larval rearing tanks daily • Feed catfish larvae with newly hatched nauplii of the brine shrimp or Artemia at 10 individuals per mL twice a day DAY 7-10 LARVAE • Larvae closely resemble the adult body form • Follow the same protocol in maintaining Day 4-6 larvae • Feed with the cladoceran Moina/Daphnia if available at 5-10 individuals/mL for another 4 days; otherwise, continue feeding Artemia nauplii • Start feeding the larvae with formulated diet (Table 3) in the morning on day 10; give natural food organisms in the afternoon • Change 50% of the water daily from thereon DAY 11-14 LARVAE • Fry measure 11-14 mm and weigh 15-20 mg • Change about 50% of the water in the larval rearing tanks daily • Give formulated diet containing 40% protein with a particle size of 150-200 microns in three rations daily at 100% of the body weight or ad libitum • Transfer larvae to nursery system on day 15 SEAFDEC Aquaculture Department 13 CULTURE OF NATURAL FOOD ORGANISMS Artemia The brine shrimp or Artemia is popularly used in rearing fish fry and postlarval crustaceans due to its high protein content. Artemia is commercially available as dry cysts, and used as freshly-hatched naulii. • A day before feeding to fish larvae, weigh 5 grams of Artemia cysts per liter • A day before use, disinfect cysts by soaking them in hypochlorite solution (add 40 mL of 5% liquid bleach or chlorox in 10 L tap or seawater) for 1520 minutes • Rinse and wash cysts with tap water/seawater on a screen • Incubate Artemia cysts in a hatching medium with seawater for 24 hours. Provide aeration • Maintain temperature within 25-30oC. Illuminate cysts continuously using 1-2 40-watt fluorescent bulbs at 10 cm above the water surface of the tank • To feed fish larvae, remove aeration from the Artemia hatching tank after 24 hours and cover the upper part with a black cloth or plastic sheet for 5 minutes to separate nauplii • Harvest Artemia nauplii by siphoning using a 100-150-micron silkscreen, starting at the very bottom of the container where nauplii are crowding Moina and Daphnia Moina and Daphnia are small crustaceans that are used as larval food for freshwater fishes. These are found in reservoirs, ponds, ditches, etc. Moina is smaller than Daphnia. Figure 13. Culture of Moina: soaking of chicken manure in a sack; tanks covered with nylon screen • Allow water to stand for 2 days in a tank • Soak chicken manure in a sack for 1-2 hours before transferring to the production tank at a rate of 20 g/ton (Fig. 13) • Add Moina/Daphnia starter • Maintain water depth at 40-50 cm • Moina/Daphnia spp. can be detected after 2-4 days • Harvest Moina/Daphnia nauplii by siphoning or draining on the 5th to 8th day of culture with an 80-100micron plankton net NURSERY Fifteen-day-old fry can be reared in net cages installed in different nursery systems e.g., pond, tank, or lake until they reach 3-5 g in body weight and 6-8 cm in total length, the recommended size for stocking in grow-out ponds. POND • Use 100-200 m2 earthen pond. Place 20-24 units of 2 x 2 x 1.5 m net cage with a mesh size of 0.5-1 cm • Provide shelters made of twigs or nets tied unto PVC pipes or placed at the bottom of each cage. Shelters should occupy about 40% of the pond bottom • Fertilize the pond water by suspending 2 sacks of cow dung on opposite corners of the pond • Apply 10-20 kg of agricultural lime per pond, settle for 3-5 days then release the old water. Let in water at a depth of 10-20 cm • Change the pond water when necessary and maintain a depth of 70 cm • Stock 15-day-old fry at 100-800 pieces/m2 (or 57-570 pieces/m3) • Feed fry (Table 3) with the same formulated diet given to fry in the hatchery phase at 20% of the average body weight during the first week, 15% on the second week, and 10% thereafter. Feeding is done in equal rations twice a day at 9 AM and 3 PM Figure 14. Net cage nursery in pond SEAFDEC Aquaculture Department 15 Table 3. Composition (%) of catfish fry/fingerling diet* Feed ingredient Peruvian fish meal Defatted soybean meal Bread flour Cod liver oil Soybean oil Vitamin mix** Mineral mix** Rice bran Total Composition (%) 35 25 10 3 3 3 1.5 19.5 100 *Estimated nutrient content (dry matter basis) : crude protein 38-40%, crude fat 10-11%, crude fiber 3-4%, crude ash 8-9%, and nitrogen-free extract or digestible carbohydrate 30-31% **Commercially available TANK • Disinfect tanks prior to use Figure 15. Net cage nursery in tank • Use 3-ton rectangular tank. Add 2-3 cm soil to cover the bottom. Place 3 units of 1 x 1 x 1.5 m net cage with a mesh size of 0.5-1 cm in each tank • Provide with shelters made of bundled nets or straw placed at the bottom of each tank. The shelter should occupy 30% of the tank bottom • Hang 10 kg of cow dung inside the tank to fertilize the water • Stock 15-day-old catfish fry at 100-400 pieces/m2 (or 57-230 pieces/m3) early in the morning or late afternoon to avoid stressing the fish • Apply the same feeding method employed in pond nursery set-up LAKE • Construct the module in accordance with the size of the cages to be installed using bamboo poles and polyrope #10. Provide set-up with wave breakers using old nets • C onstruct or fabricate 1 x 1 x 1.5 m net cages using hapa nets, polyrope #8 and polyrope #2 of 1 mm diameter (also called pamitis). This may be done simultaneously with the construction of the module 16 Breeding and seed production of the Asian catfish • Install hapa net cages in the module with at least 25% clearance from the water level. The net must be submerged at most 1 m in the water to allow fish easy access to atmospheric oxygen • Provide net cages with a feeding tray • Stock net cages with 15-day-old catfish fry at 100 pieces/m2 (or 57 pieces/m3). Stocking of fry should be done early in the morning at calm water conditions • P rovide net cages with shelters such as water hyacinth or water cabbage • A pply the same feeding method used in pond and tank nursery set-up Figure 16. Lake-based nursery set-up HEALTH MANAGEMENT Catfish may develop diseases caused by viruses, bacteria, fungi and parasites that can result in mortalities. Details on said diseases are described in Lio-Po et al. 1992; 2001 (see References section on page 22). Prevention may be achieved by practicing biosecurity measures such as requiring health certification of fish before purchase, formalin baths before purchase, applying prophylactic treatment during transport (oxytetracycline), segregating new fish stocks from existing farm stocks for at least two weeks in a separate tank, providing individual tools for each tank/pond, health monitoring of fish, etc.  If stocks show disease signs, the condition should be correctly diagnosed to determine the appropriate treatment. For most parasitic infestations and other external infections, salt water bath is suggested, or use formalin as an alternative treatment.  SEAFDEC Aquaculture Department 17 Salt bath 1 Fill the pail with about 10 liters of full-strength seawater. If seawater is not available, dissolve 200-300 g of table salt in freshwater and add up to 10 liters 2 Add aeration to the pail 3 Place the fish in a net, and dip it into the pail for 2-3 minutes 4 Transfer the fish into a tank with clean freshwater 5 Repeat the same procedures for 3-5 days Formalin bath 1 Fill the pail with 10 liters of freshwater and add 0.1 mL (or 100 µL of formalin 2 Aerate the pail vigorously 3 Place the fish inside the pail for about 1 hour 4 Transfer the fish to another container, with flow-through water for about 15-30 minutes 5 Repeat the same procedures for 3-5 days For bacterial infection, oxytetracycline can be applied as either: a Intramuscular injection for broodstock at 50 mg oxytetracycline per kg of fish per day for 10 consecutive days  b Incorporated into the feeds of larger fish at 2-4 g oxytetracycline per kg of feed for 10 consecutive days. This method is applicable only if the infected fish are eating c Bath treatment for fry and smaller juveniles           Oxytetracycline bath 1 Dissolve 10 milligrams of oxytetracycline in 1 liter freshwater and place in a pail 2 Aerate the pail vigorously 3 Place the fish inside the pail for 24 hours 4 Transfer the fish to another container containing clean water 5 Repeat the same procedures for 7 consecutive days FINANCIAL ANALYSES OF CATFISH BROODSTOCK, HATCHERY AND NURSERY OPERATIONS Table 4. Technical assumptions Items Target production/year Project duration (years) Days of culture/crop Number of runs/year Total farm area (ha) Number of cage, tank or pond Size of cage, tank or pond Age of fish (days) Number of fish/run Feeding rate (% of body weight) Cost of diet (P/kg) Stocking density Survival rate (%) Broodstock 5 12 months 4 ponds 100 m2 pond 180 20 males, 50 females 3 30 10-15 pcs/m2 0 – males, 90 – females Hatchery 1,200,000 fry 5 15 10 12 tanks 1 ton tank 4-15 120,000 50 30 1/liter 25 Nursery 300,000 fingerlings 5 60 5 0.05 12 100 m2 pond or 2 x 2 x 1.5 m cage 15-60 120,000 per ha 20, 15, 10 30 100/m2 50 Table 5. Investment items, cost and depreciation Items Total investment cost Depreciation cost per year Depreciation cost per run Salvage value after 5 years Broodstock/ hatchery 150,800 16,810 1,681 66,750 Table 6. Financial investment analysis Items Project duration Gross revenue Investment costs Total costs Net income Net present value at 12% Internal rate of return (%) Discounted benefit cost ratio (%) Broodstock/ hatchery 5 years 2,466,750 150,600 1,201,664 1,114,285 670,555 158 5.98 Nursery Pond 52,000 13,500 2,700 13,750 Lake 61,000 1,100 220 14,750 Nursery Pond Lake 3,013,750 91,000 435,996 2,590,754 1,586,068 983 49 3,014,750 114,000 350,576 2,550,174 1,624,571 865 31 SEAFDEC Aquaculture Department 19 Table 7. Costs-and-returns analysis Items Revenue Sale of fry Cost per run Total variable cost (P) Total fixed cost (P) Total cost (P) Economic indicators Income per run (P) Income per year (P) Return-on-investment (%) Payback period (years) Break-even price (P) Break-even production (pc) Total capital investment required Broodstock/ hatchery 480,000 8,560 15,204 23,764 24,236 239,667 159 0.59 0.2 600,832 167,919 Nursery Pond Lake 120,000 120,000 68,986 18,223 87,199 68,515 15,670 70,115 164,004 37 0.29 1.45 43,600 189,952 249,424 71 0.24 1.17 35,058 198,030 Table 8.1. Sensitivity analysis of catfish broodstock and hatchery operations Net income (Php) Return-oninvestment (ROI) Break-even price (Php/pc) Break-even production Net present value (NPV) at 12% (Php) Survival rate (%) 25 (1.200 M fry) 239,667 159 0.20 600,832 670,556 20 (0.960 M fry) 143,667 95 0.25 600,832 361,575 15 (0.750 M fry) 47,667 32 0.33 600,832 52,594 Price of fish (Php/pc) 0.4 239,667 159 0.20 600,832 670,556 0.3 119,667 79 0.20 801,109 284,330 0.5 359,667 238 0.20 480,665 1,056,782 0.6 479,667 318 0.20 400,554 1,443,008 Variable cost (Php) 20% increase 219,890 146 0.22 650,276 606,900 10% increase 229,778 152 0.21 625,554 638,728 20 Breeding and seed production of the Asian catfish Table 8.2. Sensitivity analysis on catfish pond nursery operations Net income (Php) Survival rate (%) 50 164,004 40 44,004 60 284,004 Price of fish (Php/pc) 2 164,004 2.3 254,004 2.5 314,004 Variable cost (Php) 20% increase 86,751 10% increase 125,378 ROI Payback period Break-even price Break-even production NPV at 12% (year) (Php/pc) (pc) (Php) 38 0.29 1.45 43,600 1,586,068 10 0.90 1.82 43,600 1,199,842 65 0.17 1.21 43,600 1,972,294 38 0.29 1.45 43,600 1,586,068 58 0.19 1.45 37,912 1,875,738 72 0.16 1.45 34,880 2,068,851 17 0.52 1.71 51,325 1,536,340 26 0.37 1.58 47,462 1,561,204 Table 8.3. Sensitivity analysis on catfish lake nursery operations Net income (Php) Survival rate (%) 50 249,424 40 129,424 60 369,424 Price of fish (Php/pc) 2 249,424 2.3 339,424 2.5 399,424 Variable cost (Php) 20% increase 180,910 10% increase 215,167 Payback Break-even Break-even NPV at ROI Period price production 12% (year) (Php/pc) (pc) (Php) 71 0.24 1.17 35,058 1,624,571 37 0.47 1.46 35,058 1,236,345 105 0.16 0.97 35,058 2,010,797 71 0.24 1.17 35,058 1,624,571 97 0.18 1.17 30,485 1,914,240 114 0.15 1.17 28,046 2,107,353 43 0.34 1.4 41,909 1,580,467 56 0.28 1.28 38,483 1,602,519 REFERENCES Areerat S. 1987. Clarias culture in Thailand. Aquaculture 63:335-362 Baldia S. 1984. Culture and utilization of Moina macrocopa Strauss as feed to tilapia fry. MS thesis, University of the Philippines Bombeo RF, AC Fermin, JD Tan-Fermin. 2002. Nursery rearing of the native catfish, Clarias macrocephalus (Gunther), at different stocking densities in cages suspended in tanks and ponds. Aquaculture Research 33:1031-1036 Carreon JA, RF Ventura, GJ Almazan. 1973. Notes on the induced breeding of Clarias macrocephalus Gunther. Aquaculture 2:5-16 Evangelista AD, NR Fortes, CB Santiago. 2005. Comparison of some live organisms and catfish diet as feed for Asian catfish Clarias macrocephalus (Gunther) larvae. Journal of Applied Ichthyology 21:1-7 Fermin AC, MEC Bolivar. 1991. Larval rearing of the Philippine freshwater catfish, Clarias macrocephalus (Gunther), fed live zooplankton and artificial diet: a preliminary study. The Israeli Journal of Aquaculture–Bamidgeh 43 (3):87-94 Fermin AC, MEC Bolivar. 1996. Weaning of the Asian catfish, Clarias macrocephalus (Gunther), larvae to formulated dry diet, pp. 83-87. In: Santiago CB, RM Coloso, OM Millamena, IG Borlongan (eds.). Feeds for Small-Scale Aquaculture. Proceedings of the National Seminar-Workshop on Fish Nutrition and Feeds. SEAFDEC Aquaculture Department, Iloilo, Philippines Fermin AC, MEC Bolivar, SBM Balad-on, JB Vargas. 1995. Improved hatchery rearing techniques for the Asian catfish Clarias macrocephalus (Gunther). In: Lavens P, E Jaspers, I Roelant (eds.). Proceedings of Larvi ’95 – Fish and Shellfish Larviculture Symposium, pp. 394-397. European Aquaculture Society, Special Publications No. 24. Ghent, Belgium Goos HJTh, CJJ Richter. 1996. Internal and external factors controlling reproduction in the African catfish, Clarias gariepinus. In: Legendre M, JP Proteau (eds.). The Biology and Culture of Catfishes, special issue of Aquatic Living Resources 9:45-58 Lavens P, P Sorgeloos. 1996. Manual on the production and use of live food for aquaculture. FAO Technical Paper 22 Breeding and seed production of the Asian catfish Legendre M, O Linhart, R Billard. 1996. Spawning and management of gametes, fertilized eggs and embryos in Siluroidei. In: Legendre M, JP Proteau (eds.). The Biology and Culture of Catfishes, special issue of Aquatic Living Resources 9:59-80 Lio-Po GD, CR Lavilla, ER Cruz-Lacierda (eds.). 2001. Health Management in Aquaculture. TID, SEAFDEC/AQD, Philippines. 187 pp Lio-Po GD, LJ Albright, C Michel, EM Leaño. 1998. Experimental induction of lesions in snakeheads (Ophicephalus striatus) and catfish (Clarias batrachus) with Aeromonas hydrophila, Aquaspirillum sp., Pseudomonas sp., and Streptococcus sp. Journal of Applied Ichthyology 14:75-79 Lio-Po GD, LJ Albright, EM Leaño. 1996. Experiments on virulence dose and portals of entry of Aeromonas hydrophila in walking catfish (Clarias batrachus). Journal of Aquatic Animal Health 8:340-343 Lio-Po GD, LJ Albright, E Tendencia. 1992. Aeromonas hydrophila in the epizootic ulcerative syndrome (EUS) of snakehead (Ophicephalus striatus) and catfish (Clarias batrachus): Quantitative estimation in natural infection and experimental induction of dermonecrotic lesions. In: M Shariff, JR Arthur, RP Subasinghe (eds.). Diseases in Asian Aquaculture. Fish Health Section, Asian Fisheries Society, Manila, Philippines. pp. 461-474 Mollah MFA. 1983. Induced spawning and larval culture of the catfish Clarias macrocephalus (Gunther). Ph.D. dissertation, Universiti Sains Malaysia, 230 pp Mollah MFA, ESP Tan. 1983. hCG-induced spawning of the catfish, Clarias macrocephalus (Gunther). Aquaculture 35:239-247 Santiago CB, AC Gonzal. 1997. Growth and reproductive performance of the Asian catfish Clarias macrocephalus (Gunther) fed artificial diets. Journal of Applied Ichthyology 13:37-40 Tan-Fermin JD. 1992. Induction of oocyte maturation and ovulation in the freshwater Asian catfish, Clarias macrocephalus by LHRHa and pimozide. Journal of Applied Ichthyology 8:90-98 Tan-Fermin JD, AC Emata. 1993. Induced spawning by LHRHa and pimozide in the Asian catfish Clarias macrocephalus (Gunther). Journal of Applied Ichthyology 9:89-96 SEAFDEC Aquaculture Department 23 Tan-Fermin JD, S Ijiri, H Ueda, S Adachi, K Yamauchi. 1997. Ovarian development and serum steroid hormone profiles in hatchery-bred female catfish Clarias macrocephalus (Gunther) during an annual reproductive cycle. Fisheries Science 63 (6):867-872 Tan-Fermin JD, T Miura, S Adachi, K Yamauchi. 1999. Seminal plasma composition, sperm motility, and milt dilution in the Asian catfish Clarias macrocephalus (Gunther). Aquaculture 171:323-338 Tan-Fermin JD, T Miura, H Ueda, S Adachi, K Yamauchi. 1997. Testicular histology and serum steroid hormone profiles in hatchery-bred male catfish Clarias macrocephalus (Gunther) during an annual reproductive cycle. Fish. Sci., 63 (5):681-686 Tan-Fermin JD, RR Pagador, RC Chavez. 1997. LHRHa and pimozide-induced spawning of Asian catfish Clarias macrocephalus (Gunther) at different times during an annual reproductive cycle. Aquaculture 148:323-331 Teugels GG. 1996. Taxonomy, phylogeny and biogeography of catfishes (Ostariophysi, siluroidei): an overview. In: Legendre M, JP Proteau (eds.). The Biology and Culture of Catfishes, special issue of Aquatic Living Resources 9:9-34 Ventura R, E Enderez. 1980. Preliminary studies on Moina sp. production in freshwater tanks. Aquaculture 21:93-96 OTHER CATFISH PAPERS BY SEAFDEC/AQD Santiago CB, AC Gonzal, M Ricci, S Harpaz. 2003. Response of bighead carp Aristichthys nobilis and Asian catfish Clarias macrocephalus larvae to free-living nematodes Panagrellus redivivus as alternative feed. Journal of Applied Ichthyology 19:239-243 Coniza EB, MR Catacutan, JD Tan-Fermin. 2003. Growth and yield of Asian catfish Clarias macrocephalus (Gunther) fed different grow-out diets. The Israeli Journal of Aquaculture-Bamidgeh 55:53-60 Erazo-Pagador G, M Shariff Din. 2001. Rapid wound healing in African catfish, Clarias gariepinus, fed diets supplemented with ascorbic acid. The Israeli Journal of Aquaculture-Bamidgeh 53:69-79. Eguia RV, MS Kamarudin, CB Santiago. 2000. Growth and survival of river catfish Mystus nemurus (Cuvier and Valenciennes) larvae fed isocaloric diets with different protein levels during weaning. Journal of Applied Ichthyology-Zeitschrift Fur Angewandte Ichthyologie 16:104-109 24 Breeding and seed production of the Asian catfish Coniza EB, JD Tan-Fermin, MR Catacutan, AT Triño, RF Agbayani. 2000. Economic evaluation of grow-out diets for Asian catfish Clarias macrocephalus (Gunther) production. University of the Philippines in the Visayas Journal of Natural Sciences 5:43-54 Tan-Fermin JD, CL Marte, H Ueda, S Adachi, K Yamauchi. 1999. Effect of season on oocyte development and serum steroid hormones in LHRHa and pimozide-injected catfish Clarias macrocephalus (Gunther). Fisheries Science 65:865-870 Lio-Po GD, GS Traxler, LJ Albright. 1999. Establishment of cell lines from catfish (Clarias batrachus) and snakeheads (Ophicephalus striatus). Asian Fisheries Science 12:343-349 Tambasen-Cheong MVP, JD Tan-Fermin, LMB Garcia, RB Baldevarona. 1995. Milt-egg ratio in artificial fertilization of the Asian freshwater catfish, Clarias macrocephalus, injected salmon gonadotropin-releasing hormone analogue and domperidone. Aquatic Living Resources 8:303-307 (note) Tan-Fermin JD. 1991. Suitability of different formalin-containing fixatives for the eggs of freshwater Asian catfish Clarias macrocephalus (Gunther). The Israeli Journal of Aquaculture-Bamidgeh 43:57-61 Fermin AC, MA Laron, DM Reyes Jr. 1991. Multiple gonadal maturation and re-maturation after hormone-induced spawning in bighead carp, Aristichthys nobilis Rich. The Philippine Scientist 28:77-88 Lio-Po GD, LH Susan Lim. 2002. Infectious diseases of warmwater fish in fresh water. In: Woo PTK, DW Bruno, LHS Lim (eds.). Diseases and Disorders of Finfish in Cage Culture; Massachusetts, USA: CABI Publishing; pp. 213-282 Tan-Fermin JD, CL Marte, S Adachi, K Yamauchi. 2001. Serum steroid hormones, reproductive and larval performance of the Asian catfish Clarias macrocephalus (Gunther) during the off-and peak reproductive seasons. In: John Yuh-Lin Yu (ed.). Proceedings of the Fourth Congress of the Asia and Oceania Society for Comparative Endocrinology (AOSCE 2000); 14-18 May 2000; Taiwan: Academia Sinica; pp. 288-297 Santiago CB, ZU Basiao, JD Tan-Fermin. 2001. Research of freshwater fishes. In: Garcia LMaB (ed.). Responsible Aquaculture Development in Southeast Asia. Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia; 12-14 October 1999. Iloilo City, Philippines. Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department; pp. 185-198 SEAFDEC Aquaculture Department 25 Laron MA, MS Kamarudin, FM Yusoff, CR Saad. 2001. Evaluation of different live food organisms on growth and survival of river catfish, Mystus nemurus (C & V) larvae. In: Hendry CI, G Van Stappen, M Wille, P Sorgeloos (eds.). Larvi '01 – Fish and Shellfish Larviculture Symposium; 3-6 September 2001; Oestende Belgium: Special publication no. 30: European Aquaculture Society; pp. 299-302 Garcia LMaB. 1996. A review of SEAFDEC/AQD finfish breeding research. In: Marte CL, GF Quinitio, AC Emata (eds.). Breeding and Seed Production of Cultured Finfishes in the Philippines. Proceedings of the SeminarWorkshop on Breeding and Seed Production of Cultured Finfishes in the Philippines; 4-5 May 1993; SEAFDEC/AQD, Tigbauan, Iloilo, Philippines. Iloilo, Philippines: SEAFDEC Aquaculture Department; pp. 54-64 Emata AC. 1995. Research on marine and freshwater fishes. In: Bagarinao TU, EEC Flores (eds.). Towards Sustainable Aquaculture in Southeast Asia and Japan. Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia; 26-28 July 1994; Iloilo City, Philippines. Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department; pp. 166-186 (Preliminary Report) Tan-Fermin JD, RSJ Gapasin, AM Tan, MA Garcia, AC Emata. 1994. LHRHa and pimozide-induced breeding in the catfish, Clarias macrocephalus (Gunther). In: Chou LM, AD Munro, TJ Lam, TW Chen, LKK Cheong, JK Ding, KK Hooi, HW Khoo, VPE Phang, KF Shim, CH Tan (eds.). The Third Asian Fisheries Forum. Proceedings of the Third Asian Fisheries Forum; 26-30 October 1992; Singapore. Manila, Philippines: Asian Fisheries Society; pp. 830-833 Basiao ZU. 1994. Tilapia, carp, and catfish. In: Lacanilao F, RM Coloso, GF Quinitio (eds.). Proceedings of the Seminar-Workshop on Aquaculture Development in Southeast Asia and Prospects for Seafarming and Searanching; 19-23 August 1991; Iloilo City, Philippines. Tigbauan, Iloilo, Philippines: SEAFDEC Aquaculture Department; pp. 24-31 Lio-Po GD, LJ Albright, EV Alapide-Tendencia. 1992. Aeromonas hydrophila in the epizootic ulcerative syndrome (EUS) of snakehead, Ophicephalus striatus, and catfish, Clarias batrachus: quantitative estimation in natural infection and experimental induction of dermo-muscular necrotic lesion. In: Shariff M, RP Subasinghe, JR Arthur Jr. (eds.). Diseases in Asian Aquaculture I. Proceedings of the First Symposium on Diseases in Asian Aquaculture; 26-29 November 1990; Bali, Indonesia. Manila, Philippines: Asian Fisheries Society; pp. 461-474 ABOUT THE AUTHORS Dr. Josefa D. Tan-Fermin is a Scientist of the Breeding Section at AQD. She first worked as a research assistant under the Milkfish Broodstock Development Project in June 1979, eventually becoming a research associate in 1982. She finished her BSc in Biological Sciences in 1977 from the University of the Philippines in the Visayas (UPV), MSc in Zoology in 1982 from UP Diliman, and Doctor in Fisheries Science in 1997 from the Faculty of Fisheries, Hokkaido University. Dr. Tan-Fermin has worked on the different aspects of the reproductive biology and digestive physiology of milkfish, shrimp, sea bass, grouper, goldfish and catfish. These works were published mainly in refereed journals. Her doctoral dissertation and work on native catfish are results of continuing efforts to save this fish from extinction here in the Philippines. Mr. Armando C. Fermin holds the position of Scientist and is currently the Program Leader of the Integrated Mollusk Program at AQD. He has more than 28 years of experience in aquaculture research, training, and extension obtained from his two employers, Central Luzon State University (CLSU) in Nueva Ecija, and AQD in Tigbauan, Iloilo. He worked on freshwater and marine aquaculture species like giant prawn, bighead carp, native catfish, seabass, and tropical abalone. He has published more than 30 articles in local and international journals and proceedings. He is a member of the International Abalone Society, Asian Fisheries Society, Network of Tropical Aquaculture Scientists, Tropical Marine Mollusks Programme, Philippine Aquaculture Society, and the National Research Council of the Philippines. He finished his BSc and MSc degrees from CLSU. Ms. Ruby F. Bombeo is an Information Specialist of the Training and Information Division of AQD. She joined AQD as Research Technician in 1977. She has worked on natural food for fishes and the hatchery and nursery rearing of catfish. Along with her co-authors, she was a recipient of the Department of Agriculture (DA) Secretary's Award for Best Paper in the Aquaculture Research Category for the paper "Nursery rearing of the Asian catfish, Clarias macrocephalus (Gunther), at different stocking densities in cages suspended in tanks and ponds." She finished her BSc in Biology from Central Philippine University and her MSc in Fisheries (Aquaculture) from UPV. SEAFDEC Aquaculture Department 27 Ms. Ma. Antonietta D. Evangelista is an Associate Researcher at AQD. She currently works on the culture of natural food organisms, and on the breeding, seed production and farming of the Asian catfish at the Binangonan Freshwater Station of AQD in Binangonan, Rizal. Her work on the “Culture of Ceriodaphnia cornuta in tanks and their utilization in the hatchery production of some freshwater fish species” won the 2004 AFMA R&D Paper Award (Agriculture and Fisheries Modernization Act for Research and Development) during the 16th National Research Symposium given by DA's Bureau of Agricultural Research. She earned her BSc in Fishery Education (cum laude) from Aklan National College of Fisheries in New Washington, Aklan and her Masters degree in Fisheries from UPV. Dr. Mae R. Catacutan is a Scientist at AQD. She started working in 1978 as Research Aide of the Nutrition and Feed Development Section. Her work on aquaculture nutrition includes digestibility of feed ingredients, protein requirement, and vitamin C for popular species for culture. Her research work on the nutrition of important aquaculture species have been published in international journals. She graduated from Silliman University with a BSc Chemistry degree (cum laude) as a national state scholar. She obtained her MSc and PhD in Fisheries Science from Kagoshima University through scholarships from the Japanese government. She is a member of the Integrated Chemists of the Philippines, Asian Fisheries Society, and the National Research Council of the Philippines. Dr. Corazon B. Santiago is a retired Scientist of AQD. Her work has been focused on establishing nutrient requirements of the larvae and broodstock of some freshwater fishes and developing fish feeds. She was also involved in a European Union-funded project on lake ecology and was active in the training projects of AQD. Dr. Santiago has published scientific papers in international and local journals and proceedings. Two of her publications were awarded the 1991 DABFAR Second Best Paper Award for Fisheries & Aquatic Resources and a special award at the 11th Dr. Elvira O. Tan Memorial Research Awards in 1997. She earned her BSc at the Mindanao State University (summa cum laude) and her MSc And PhD (major in fish nutrition) at Auburn University. She started her career as an instructor-researcher in 1972 at MSU Sulu College of Technology and Oceanography in Tawi-Tawi and in Naawan, Misamis Oriental. ACKNOWLEDGMENT We thank Ms. Edith Panes, Ms. Rosemarie Chavez, Ms. Lillian Gustilo, Messrs. Alfredo Tan, Pastor Jones Denusta, Dennis Candia, Joval Martinez, Angelo Sontillano, Rosenio Pagador, and Teodoro Traviña for assisting in the conduct of the various studies that led to the refinement of breeding and seed production of the native catfish. The inputs of Dr. Nerissa Salayo and Ms. Dianne Hope Tormon on the financial analyses of the catfish hatchery and nursery operations, and Dr. Gilda Lio-Po on disease management are very much appreciated. We are also grateful to Mr. Rommel Guarin for the layout, and to Ms. Milagros Castaños, Drs. Clarissa Marte, Evelyn Grace Ayson and Joebert Toledo for reviewing the earlier versions of this manual. RECENT SEAFDEC PUBLICATIONS AQUACULTURE EXTENSION MANUALS (AEM) and STATE-OF-THE-ART SERIES (SAS) AEM 41 Grow-out Culture of the Asian Catfish Clarias macrocephalus (Gunther). EB Coniza et al. (2008). 29 pp AEM 40 Breeding and Seed Production of the Asian Catfish Clarias macrocephalus (Gunther). JD Tan-Fermin et al. (2008). 31 pp AEM 39 Abalone Hatchery. AC Fermin et al. (2008). 31 pp AEM 38 Tilapia Broodstock and Hatchery Management. R Eguia, MRR Eguia (2007). 48 pp AEM 37 Giant Clam Hatchery, Ocean Nursery and Stock Enhancement. SS Mingoa-Licuanan, E Gomez (2007). 110 pp AEM 36 Tilapia Farming in Cages and Ponds. RV Eguia, MRR Eguia (2004). 40 pp (in print or CD). AEM 35 Best Management Practices for Mangrove-Friendly Shrimp Farming. DD Baliao, S Tookwinas (2002). 50 pp (Filipino version also available) AEM 34 Biology and Hatchery of Mud Crabs Scylla spp. ET Quinitio, FD Parado-Estepa (2008, 2nd ed.). 47 pp AEM 33 Induced Breeding and Seed Production of Bighead Carp. AC Gonzal et al. (2001). 40 pp AEM 32 The Farming of the Seaweed Kappaphycus. AQ Hurtado, RF Agbayani (2000). 26 pp (Filipino version also available) AEM 30 Net Cage Culture of Tilapia in Dams and Small Farm Reservoirs. DD Baliao et al. (2000). 14 pp AEM 29 Grouper Culture in Floating Net Cages. DD Baliao et al. (2000). 10 pp AEM 26 Pen Culture of Mudcrab in Mangroves. DD Baliao et al. (1999). 10 pp AEM 24 Grouper Culture in Brackishwater Ponds. DD Baliao et al. (1998). 18 pp AEM 23 Pagpapaanak ng Tilapya. RV Eguia et al. (2007). 64 pp AEM 22 Pag-aalaga ng Tilapya. RV Eguia et al. (2007). 68 pp AEM 21 Feeds and Feeding of Milkfish, Nile Tilapia, Asian Sea Bass and Tiger Shrimp. Feed Development Section (1994). 97 pp AEM 16 Diseases of Penaeid Shrimps in the Philippines. CR Lavilla-Pitogo et al. (2000) 83 pp SAS Environment-Friendly Schemes in Intensive Shrimp Farming. DD Baliao (2000). 24 pp SAS Closed Recirculating Shrimp Farming System. S Tookwinas (2000). 28 pp TEXTBOOKS, MONOGRAPHS, LABORATORY BOOKS Seaweeds of Panay (2006). AQ Hurtado et al. 50 pp, 2nd ed. Diseases in Farmed Mud Crabs Scylla spp.: Diagnosis, Prevention and Control (2004). CR Lavilla-Pitogo, LD de la Peña. 89 pp (in print or CD) Diseases of Cultured Groupers (2004). K Nagasawa, ER Cruz-Lacierda (eds.). 81 pp (in print or CD) Handbook of the Mangroves of the Philippines – Panay (2004). JH Primavera et al. 106 pp Laboratory Manual of Standardized Methods for the Analysis of Pesticide and Antibiotic Residues in Aquaculture Products (2004). IG Borlongan, JNP Chuan. 46 pp (in print or CD) Laboratory Manual of Standardized Methods for Antibicrobial Sensitivity Tests for Bacteria Isolated from Aquatic Animals and Environment (2004). L Ruangpan, EA Tendencia. 55 pp (in print or CD) Nutrition in Tropical Aquaculture (2002). OM Millamena et al. (eds.). 221 pp Health Management in Aquaculture (2001). GL Po et al. (eds.). 187 pp An Assessment of the Coastal Resources of Ibajay and Tangalan, Aklan (2001). LMB Garcia (ed.). 60 pp Ecology and Farming of Milkfish (1999). TU Bagarinao. 117 pp CONFERENCE PROCEEDINGS Proceedings of the Regional Technical Consultation on Stock Enhancement (2006). JH Primavera, ET Quinitio, MR Eguia (eds.). 150 pp Responsible Aquaculture Development in Southeast Asia (2001). LMB Garcia (ed.). 274 pp Mangrove-Friendly Aquaculture(2000). JH Primavera et al. (eds.). 217 pp FOR FREE DOWNLOADS, VISIT: www.seafdec.org.ph/publications Flyers, reports, newsletters, video, photos 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, the 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 conducts research on fisheries problems; generates appropriate fisheries technologies; trains researchers, technicians, fishers and aquafarmers, and managers; disseminates information on fisheries science and technologies; and recommends policies pertaining to the fisheries sector. 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 SEAFDEC/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 SEAFDEC/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.