Seed Production of the Native Catfish (Hito)

August 5, 2008 by Leo   5,133 Views

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The freshwater catfish Clarias macrocephalus is native to the Philippines but is fast becoming scarce in many natural habitats.

It is a favorite food fish due to its tender and delicious meat. Recently, farming of C. macrocephalus has gained interest among catfish growers. Like other catfish species, it is resistant to diseases, can be stocked at high densities, and tolerates low water quality.

The catfishes C. macrocephalus and C. batrachus are almost similar in size and appearance, but differ by the shape of the occipital process in the head portion. The occipital process is blunt or rounded in C. macrocephalus and pointed in C. batrachus. C. macrocephalus also has small white spots along the sides of the body.

Broodstock Development and Management

Catfish broodstock can be obtained from lakes, rivers, tributaries and other freshwater bodies, and caught by hand or indigenous fish traps. C. macrocephalus was reported to abound in the Bicol region, Palawan, and some areas in Mindanao.

Sexes are separate in catfish. Males have elongated urogenital papillae around the anus, whereas females have a simple round opening.

Catfish are carnivores, but can feed on small bottom dwelling animals, rice bran, kitchen refuse, fish meal, or formulated feeds. Broodstock fed a SEAFDEC-formulated diet with 43% protein had similar reproductive and larval quality as those fed “trash fish.”

Catfish mature at about 6-8 months of age. Larger mature females produce more eggs than smaller females. About 20-90 eggs/g body weight (BW) can be stripped from a gravid female after hormone injection.

Breeding

Captive C. macrocephalus contain eggs and sperm the whole year but do not spawn by themselves. Artificial propagation of C. macrocephalus involves inducing the gravid females to spawn by injection of different hormones, and manually stripping the eggs

after several hours. Before females are stripped of eggs, male catfish are sacrificed. The male reproductive tract is then dissected and macerated to obtain the milt to fertilize the eggs. (click image to enlarge)

Success in induced spawning depends largely on knowledge of (i) the optimum dose of hormones to be used, and (ii) latency period, the time between injection of hormones and stripping of eggs. Induced spawning of C. macrocephalus can be done in any of the following ways:

Hatchery

Four to five days after hatching, catfish larvae are stocked at 30 per liter in bigger tanks. They are fed natural food organisms such as newly hatched brine shrimp Artemia for three days, and the water flea Moina for another four days. Thereafter, larvae can be weaned to formulated diets with 44% protein and particle size 150-200 ?m. The diet is given twice daily to two- to four-week old catfish fry at a feeding rate of 20% BW and to older fry at 5-10% BW.

Nursery

The nursery tank or pond is fertilized ten days before stocking of catfish fry. Fifteenday old fry may be stocked at 200-800/m2 in tanks and up to 1200/m2 in ponds. More fingerlings can be obtained when the fry are grown in net

cages suspended in either tanks or ponds. Fingerlings are harvested after 28 days, ready for stocking in grow-out ponds.

For further information, contact

Catfish ProjectSEAFDEC Aquaculture DepartmentTigbuan, IloiloTel: (033) 335-1009, 336-2965, 336-2937Fax: (033) 335-1008, 336-2891Email: aqdchief@aq.seafdec.org.ph, d_chief@i-iloilo.com.ph

Profitability Assessment: A Case Study of African Catfish (Clarias gariepinus) Farming in the Lake Victoria Basin, Kenya 

 

John Kengere Okechi,

KMFRI,Kisumu,Kenya 

Páll Jensson, Professor University of Iceland,Reykjavik 

Motivation 

No reports on the economic evaluation of aquaculture production systems in Kenya (other than the few case studies on tilapia).

Yet economic considerations are crucial in the selection of an appropriate aquaculture production system.

Currently aquaculture is almost entirely for subsistence, with little surplus production being sold in the rural market.

Fish farmers lack information on how to asses profitability This has hampered aquaculture development in the country.

Study area   

Basin/Catchment area: 38,913 Km2

Densely populated = 9 million people

Annul rainfall of 1,000 – 13,000 mm

Temperature range of 14 – 340C

Multi-river basin 

*Enhanced potential for

Aquaculture development.

    

Aquaculture contribution to total fish production in Kenya

(adapted from FAO 2002)  

Background information 

Annual Production:

Average: 180,000 Metric tonnes (MT)

Commercially important fish species:

Lates niloticus (Nile perch) = 58%

Rastrineobola argentea (Dagaa) = 30%

Oreochromis niloticus (Nile tilapia) = 10%

Aquaculture < 1% of the total production

(main species: tilapia, trout & catfish)

    

Why catfish farming? 

Grows fast and feeds on a large variety of agriculture by-products. Can be raised in high densities resulting in high net yields (6–16 t/ha/year). Higher price than tilapia as it can be sold live at the market. Hardy and can tolerate adverse water quality conditions.

    

Goal/Vision 

To develop a decision support tool for profitability assessment of fish farming.

  To study the Feasibility of Catfish farming in the Lake Victoria Basin.

  The vision: This might in the future be valuable for the sustainability of fish

farming in Kenya.

    

Fish Farming Assumptions

    

Investment Assumptions

    

Production Assumptions

    

The models developed 

Production model for one pond Production model for 12 ponds

Profitability model: Investment & Financing Operating Statement Balance Sheet Cash Flow Profitability Measures & Sensitivity Analysis

    

One pond model 

Pond size 800 m2 Stocked with 4000 fingerlings at 5 / m2

Limed at a rate of 5 tonnes ha-1

Urea at a rate of 90 kg ha-1

DAP at a rate of 30 kg ha-1

Supplementary feed (daily) After every 2 weeks pond is sampled (mean body wts & % survival rates) Used to compute biomass of fish in pond Based on biomass fish is fed daily for culture period of 28 weeks Fish harvested, net production weight determined & sold at Ksh. 120/kg

    

One pond production model 

Production data on monoculture of the African catfish, density 5 fingerlings m2, mean temperature 25-27 °C

    

Summary: Revenue, costs and net profit contribution.

    

Twelve pond model 

Information from one pond used to prepare production planning model for 1-ha (12 ponds each 800 m2)

Two ponds stocked with catfish fingerlings every month to have continuos production

After 6 months in operation all 12 ponds were stocked and the first 2 ponds harvested in the 8th month

Economics of scale

    

Production schedule for 1-ha (12 ponds)

catfish farm during first year of operations 

>Able to tell how much of the

resources needed at any

particular time of operations 

In stocking more than one pond,

benefits from the economies

of scale

    

2nd year of operations 

Yields

Yr 1 : 9 t/ha

Yr 2: 12 t/ha

  

  

Profitability model

    

Investment & Cash Flow chart

    

Profitability measure: NPV

    

Profitability measure: IRR

    

Sensitivity analysis

    

Conclusions 

Purpose of study: To develop a generic tool to assess the profitability of fish farming.

A valuable management tool to aquaculture farmers, investors and financial institutions and banks.

Based on the assumptions and analysis of the model, catfish farming appears feasible and profitable along the LakeVictoria Basin, 9t/ha/yr -12t/ha/yr.

Need to test modeled yields in real farm situation Uncertainties and risks: Monte Carlo simulation

    

By-products 

Two documents developed:

Brochure: Fish Farming-getting started

  Record keeping and data collection for small scale fish farming

    

For your attention 

Farm catfish & make money

Catfish

From Wikipedia, the free encyclopedia

Jump to: navigation, searchFor other uses, see Catfish (disambiguation).

CatfishFossil range: Late Cretaceous - Present

small-tailed catfish

Scientific classificationKingdom: AnimaliaPhylum: ChordataClass: OsteichthyesSuperorder: OstariophysiOrder: Siluriformes

Families

AkysidaeAmblycipitidaeAmphiliidaeAnchariidaeAndinichthyidae †AriidaeAspredinidaeAstroblepidaeAuchenipteridaeAustroglanididaeBagridaeCallichthyidaeCetopsidaeChacidaeClariidaeClaroteidaeCranoglanididaeDiplomystidaeDoradidaeErethistidaeHeptapteridaeHypsidoridae †IctaluridaeLacantuniidaeLoricariidaeMalapteruridaeMochokidaeNematogenyiidaePangasiidaePimelodidaePlotosidaePseudopimelodidaeSchilbeidaeScoloplacidaeSiluridaeSisoridaeTrichomycteridae

incertae sedis  Conorhynchos  Horabagrus  Phreatobius

Catfish (order Siluriformes) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest, the Mekong giant catfish from Southeast Asia and the longest, the wels catfish of Eurasia, to detritivores (species that eat dead material on the bottom), and even to a tiny parasitic species commonly called the candiru, Vandellia cirrhosa. There are armour-plated types and also naked types, neither having scales. Despite their name, not all catfish have prominent barbels; members of the Siluriformes order are defined by features of the skull and swimbladder. Catfish are of considerable commercial importance; many of the larger species are farmed or fished for food. Many of the smaller species, particularly the genus Corydoras, are important in the aquarium hobby.

Contents[hide]

1 Distribution and habitat 2 Physical characteristics

o 2.1 External anatomy of catfish o 2.2 Size o 2.3 Internal anatomy

3 Catfish as food 4 Aquaculture 5 Catfish as invasive species 6 Dangers to humans 7 Taxonomy 8 References

9 External links

[edit] Distribution and habitat

Extant catfish species live in inland or coastal waters of every continent except Antarctica. Catfish have inhabited all continents at one time or another.[1] Catfish are most diverse in tropical South America, Africa, and Asia.[2] More than half of all catfish species live in the Americas. They are the only ostariophysans that have entered freshwater habitats in Madagascar, Australia, and New Guinea.[3]

They are found in freshwater environments of all kinds, though most inhabit shallow, running water.[3] Representatives of at least eight families are hypogean (live underground) with three families that are also troglobitic (inhabiting caves).[4][5] One such species is Phreatobius cisternarum, known to live underground in phreatic habitats.[6]

Numerous species from the families Ariidae and Plotosidae, and a few species from among the Aspredinidae and Bagridae, are found in salt water.[7][8]

[edit] Physical characteristics

[edit] External anatomy of catfish

Most catfish are bottom feeders. In general, they are negatively buoyant, which means that they will usually sink rather than float due to a reduced gas bladder and a heavy, bony head.[3] Catfish have a variety of body shapes, though most have a cylindrical body with a flattened ventrum to allow for benthic feeding.[3]

A flattened head allows for digging through the substrate as well as perhaps serving as a hydrofoil. Most have a mouth that can expand to a large size and contains no incisiform teeth; catfish generally feed through suction or gulping rather than biting and cutting prey.[3] However, some families, notably Loricariidae and Astroblepidae, have a suckermouth that allows them to fasten themselves to objects in fast-moving water. Catfish also have a maxilla reduced to a support for barbels; this means that they are unable to protrude their mouths as other fish such as carp.[3]

The channel catfish has four pairs of barbels.

Catfish may have up to four pairs of barbels: nasal, maxillary (on each side of mouth), and two pairs of chin barbels, although pairs of barbels may be absent, depending on the species. Because their barbels are more important in detecting food, the eyes on catfish are generally small. Like other ostariophysans, they are characterized by the presence of a Weberian apparatus.[1] Their well-developed Weberian apparatus and reduced gas bladder allow for improved hearing as well as sound production.[3]

The armor plates are evident in Corydoras semiaquilus.

Catfish have no scales; their bodies are often naked. In some species, the mucus-covered skin is used in cutaneous respiration, where the fish breathes through its skin.[3] In some catfish, the skin is covered in bony plates called scutes; some form of body armor appears in various ways within the order. In loricarioids and in the Asian genus Sisor, the armor is primarily made up of one or more rows of free dermal plates. Similar plates are found in large specimens of Lithodoras. These plates may be supported by vertebral processes, as in scoloplacids and in Sisor, but the processes never fuse to the plates or form any external armor. By contrast, in the subfamily Doumeinae (family Amphiliidae) and in hoplomyzontines (Aspredinidae), the armor is formed solely by expanded vertebral processes that form plates. Finally, the lateral armor of doradids, Sisor, and hoplomyzontines consists of hypertrophied lateral line ossicles with dorsal and ventral lamina.[9]

A sting from the striped eel catfish, Plotosus lineatus, may be fatal.

All catfish, except members of Malapteruridae (electric catfish), possess a strong, hollow, bonified leading spine-like ray on their dorsal and pectoral fins. As a defense, these spines may be locked into place so that they stick outwards, which can inflict severe wounds.[2] In several species catfish can use these fin rays to deliver a stinging protein if the fish is irritated.[10] This venom is produced by glandular cells in the epidermal tissue covering the spines.[1] In members of the family Plotosidae, and of the genus Heteropneustes, this protein is so strong it may hospitalize humans unfortunate enough to receive a sting; in Plotosus lineatus, the stings may result in death.[1]

Juvenile catfish, like most fish, have relatively large heads, eyes and posterior median fins in comparison to larger, more mature individuals. These juveniles can be readily placed in their families, particularly those with highly derived fin or body shapes; in some cases identification of the genus is possible. As far as known for most catfish, features that are often characteristic of species such as mouth and fin positions, fin shapes, and barbel lengths show little difference between juveniles and adults. For many species, pigmentation pattern is also similar in juveniles and adults. Thus, juvenile catfishes generally resemble and develop smoothly into their adult form without distinct juvenile specializations. Exceptions to this are the ariid catfishes, where the young retain yolk sacs late into juvenile stages, and many pimelodids, which may have elongated barbels and fin filaments or coloration patterns.[11]

Sexual dimorphism is reported in about half of all families of catfish.[12] The modification of the anal fin into an intromittent organ (in internal fertilizers) as well as accessory

structures of the reproductive apparatus (in both internal and external fertilizers) have been described in species belonging to 11 different families.[13]

[edit] Size

Catfish have one of the greatest range in size within a single order of bony fish.[3] Many catfish have a maximum length of under 12 cm.[1] Some of the smallest species of Aspredinidae and Trichomycteridae reach sexual maturity at only 1 centimetre (0.39 in).[2]

The wels catfish, Silurus glanis, is the only native catfish species of Europe, besides the much smaller related Aristotle's catfish found in Greece. Mythology and literature record wels catfish of astounding proportions, yet to be proven scientifically. The average size of the species is about 1.2–1.6 m (3.9–5.2 ft), and fish more than 2 metres (6.6 ft) are very rare. The largest specimens on record measure more than 2.5 metres (8.2 ft) in length and sometimes exceeded 100 kilograms (220 lb).

The largest Ictalurus furcatus, caught in the Mississippi River on May 22, 2005, weighed 124 pounds (56 kg). The largest flathead catfish, Pylodictis olivaris, ever caught was in Independence, Kansas, weighing 123 lb 9 oz (56.0 kg). In July 2009, a catfish weighing 193 pounds was caught in the River Ebro, Spain, by a 11-year old British schoolgirl.[14] However, these records pale in comparison to a giant Mekong catfish caught in northern Thailand in May 1, 2005 and reported to the press almost 2 months later that weighed 293 kilograms (650 lb). This is the largest giant Mekong catfish caught since Thai officials started keeping records in 1981.[15] The giant Mekong catfish are not well studied since they live in developing countries and it is quite possible that they can grow even larger.

[edit] Internal anatomy

In many catfish, the humeral process is a bony process extending backward from the pectoral girdle immediately above the base of the pectoral fin. It lies beneath the skin where its outline may be determined by dissecting the skin or probing with a needle.[16]

The retina of catfish are composed of single cones and large rods. Many catfish have a tapetum lucidum which may help enhance photon capture and increase low-light sensitivity. Double cones, though present in most teleosts are absent from catfish.[17]

The anatomical organization of the testis in catfish is variable among the families of catfish, but the majority of them present fringed testis: Ictaluridae, Claridae, Auchenipteridae, Doradidae, Pimelodidae, and Pseudopimelodidae.[18] In the testes of some species of Siluriformes, organs and structures such as a spermatogenic cranial region and a secretory caudal region are observed, in addition to the presence of seminal vesicles in the caudal region.[19] The total number of fringes and their length are different in the caudal and cranial portions between species.[18] Fringes of the caudal region may present tubules, in which the lumen is filled by secretion and spermatozoa.[18]

Spermatocysts are formed from cytoplasmic extensions of Sertoli cells; the release of spermatozoa is allowed by breaking of the cyst walls.[18]

The occurrence of seminal vesicles, in spite of their interspecific variability in size, gross morphology and function, has not been related to the mode of fertilization. They are typically paired, multi-chambered, and connected with the sperm duct, and have been reported to play a glandular and a storage function. Seminal vesicle secretion may include steroids and steroid glucuronides, with hormonal and pheromonal functions, but it appears to be primarily constituted of mucoproteins, acid mucopolysaccharides, and phospholipids.[13]

Fish ovaries may be of two types: gymnovarian or cystovarian. In the first type, the oocytes are released directly into the coelomic cavity and then eliminated. In the second type, the oocytes are conveyed to the exterior through the oviduct.[19] Many catfish are cystovarian in type, including Pseudoplatystoma corruscans, P. fasciatum, Lophiosilurus alexandri, and Loricaria lentiginosa.[18][19]

[edit] Catfish as food

Tuscaloosa Catfish served with corn bread and rice

Catfish have been widely caught and farmed for food for hundreds of years in Africa, Asia, Europe, and North America. Judgments as to the quality and flavor vary, with some food critics considering catfish as being excellent food, others dismiss them as watery and lacking in flavour.[20] In Central Europe, catfish were often viewed as a delicacy to be enjoyed on feast days and holidays. Migrants from Europe and Africa to the United States brought along this tradition, and in the southern United States catfish is an extremely popular food. The most commonly eaten species in the United States are the channel catfish and blue catfish, both of which are common in the wild and increasingly widely farmed. Farm-raised catfish became such a staple of the diet of the United States that on June 25, 1987, President Ronald Reagan established National Catfish Day to recognize "the value of farm-raised catfish."

Catfish is eaten in a variety of ways; in Europe it is often cooked in similar ways to carp, but in the United States it is typically crumbed with cornmeal and fried.[20] In Indonesia catfish are usually served grilled in street stalls called warung and eaten with vegetables; the dish is called Pecel Lele (Lele is the Indonesian word for catfish). In Malaysia catfish, called "Ikan Keli," is fried with spices and is often eaten with steamed rice. Vietnamese

catfish cannot be legally marketed as catfish in the US, and is subsequently referred to as "swai."[21]

Catfish is high in Vitamin D.[22] Farm-raised catfish contains low levels of omega-3 fatty acids and a much higher proportion of omega-6 fatty acids.[23]

As catfish lack scales, they are judged to not be kosher and cannot be eaten by observant Jews.

[edit] AquacultureMain article: Aquaculture of catfish

Catfish are easy to farm in warm climates, leading to inexpensive and safe food at local grocers. Ictalurids are cultivated in North America (especially in the Deep South, with Mississippi being the largest domestic catfish producer).[24] Channel catfish (Ictalurus punctatus) supports a $450 million/yr aquaculture industry.[2] In Central Louisiana, Morgan W. Walker, Jr., an Alexandria businessman, in 1970 converted a 1,100-acre cattle ranch into catfish ponds to raise fish on a mass scale for sale and consumption.[25]

Catfish raised in inland tanks or channels are considered safe for the environment, since their waste and disease should be contained and not spread to the wild.[26]

In Asia, many catfish species are important as food. Several walking catfish (Clariidae) and shark catfish (Pangasiidae) species are heavily cultured in Africa and Asia. Exports of one particular shark catfish species from Vietnam, Pangasius bocourti, has met with pressures from the U.S. catfish industry. In 2003, The United States Congress passed a law preventing the imported fish from being labeled as catfish.[27] As a result, the Vietnamese exporters of this fish now label their products sold in the U.S. as "basa fish." Trader Joe's has labeled frozen fillets of Vietnamese Pangasius hypothalmus as "striper."[28]

There is a large and growing ornamental fish trade, with hundreds of species of catfish, such as Corydoras and armored suckermouth catfish (often called plecos), being a popular component of many aquaria. Other catfish commonly found in the aquarium trade are banjo catfish, talking catfish, and long-whiskered catfish.

[edit] Catfish as invasive species

Walking catfish is an invasive species in Florida.

Representatives of the genus Ictalurus have been introduced into European waters in the hope of obtaining a sporting and food resource. However, the European stock of American catfishes has not achieved the dimensions of these fish in their native waters, and have only increased the ecological pressure on native European fauna. Walking catfish have also been introduced in the freshwaters of Florida, with the voracious catfish becoming a major alien pest there. Flathead catfish, Pylodictis olivaris, is also a North American pest on Atlantic slope drainages.[2] Pterygoplichthys species, released by aquarium fishkeepers, have also established feral populations in many warm waters around the world.[29][30][31][32][33]

[edit] Dangers to humansThis section needs additional citations for verification.Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (July 2009)

While the vast majority of catfish are harmless to humans, a few species are known to present some risk. Perhaps the most notorious of these is the Candiru, due to the way it is reputed to parasitize the urethra, though there is only one well-documented case of a candiru attack on a human. Since 2007, the Goonch catfish has also gained attention following a series of fatal underwater attacks which have been alleged by biologist Jeremy Wade to have been from unusually large goonch. The Wels catfish has also been reputed to kill humans (especially young children), and while there are no documented cases of fatalities, larger specimens are known to cause serious injuries in rare instances (probably from defensive reactions rather than attempted predation). In addition, other species are reputed to be dangerous to humans as well, but with less definitive evidence.

[edit] Taxonomy

The catfishes are a monophyletic group. This is supported by molecular evidence.[34]

Catfish belong to a superorder called the Ostariophysi, which also includes the Cypriniformes, Characiformes, Gonorynchiformes and Gymnotiformes, a superorder characterized by the Weberian apparatus. Some place Gymnotiformes as a sub-order of Siluriformes, however this is not as widely accepted. Currently, the Siluriformes are said to be the sister group to the Gymnotiformes, though this has been debated due to more recent molecular evidence.[1] As of 2007 there are about 36 extant catfish families, and about 3,023 extant species have been described.[35] This makes the catfish order the second or third most diverse vertebrate order; in fact, 1 out of every 20 vertebrate species is a catfish.[2]

The taxonomy of catfishes is quickly changing. In a 2007 and 2008 paper, Horabagrus, Phreatobius, and Conorhynchos were not classified under any current catfish families.[35] There is disagreement on the family status of certain groups; for example, Nelson (2006) lists Auchenoglanididae and Heteropneustidae as separate families, while the All Catfish Species Inventory (ACSI) includes them under other families. Also, FishBase and the Integrated Taxonomic Information System lists Parakysidae as a separate family, while

this group is included under Akysidae by both Nelson (2006) and ACSI.[1][36][37][38] Many sources do not list the recently revised family Anchariidae.[39] The family Horabagridae, including Horabagrus, Pseudeutropius, and Platytropius, is also not shown by some authors but presented by others as a true group.[34] Thus, the actual number of families differs between authors. The species count is in constant flux due to taxonomic work as well as description of new species. On the other hand, our understanding of catfishes should increase in the next few years due to work by the ACSI.[1]

The rate of description of new catfishes is at an all-time high. Between 2003 and 2005, over 100 species have been named, a rate three times faster than that of the past century.[40] In June, 2005, researchers named the newest family of catfish, Lacantuniidae, only the third new family of fish distinguished in the last 70 years (others being the coelacanth in 1938 and the megamouth shark in 1983). The new species in Lacantuniidae, Lacantunia enigmatica, was found in the Lacantun river in the Mexican state of Chiapas.[41]

According to morphological data, Diplomystidae is usually considered to be the most primitive of catfishes and the sister group to the remaining catfishes, grouped in a clade called Siluroidei. Recent molecular evidence contrasts the prevailing hypothesis, where the suborder Loricarioidei are the sister group to all catfishes, including Diplomystidae (Diplomystoidei) and Siluroidei; though they were not able to reject the past hypothesis, the new hypothesis is not unsupported. Siluroidei was found to be monophyletic without Loricarioid families or Diplomystidae with molecular evidence; morphological evidence is unknown that supports Siluroidei without Loricarioidea.[34]

Below is a list of family relationships by different authors. Lacantuniidae is included in the Sullivan scheme based on recent evidence that places it sister to Claroteidae.[42

Franchising Raising and production of catfish (Hito)

There are two common varieties of catfish in the Philippines—one that is our own native hito that thrives in rice fields and rivers, sometimes in muddy places; and the other one brought over from Thailand or Taiwan. Both kinds can be raised and grown commercially. Within four months, hito can grow as big as a size weighing 300-400 grams or three in a kilo. In Taiwan, they grow hito as big as two kilos each.

Clarias batrachus is a black, slippery fish with moustache to aid it in swimming. It is called catfish in English, hito in Ilocos, ito in Pampanga, and pantatin in Pangasinan, Cebu and Iloilo. Catfish are usually found in marshes, ricefields, swamps, streams, rivers, lakes irrigation canals, or in any body or fresh water.

Catfish farming requires extremely heavy stocking (75 to 100 fingerlings per squire meter) and intensive feeding (90 per cent protein). Hito fry supplies are few; thus, those who go into catfish raising depend on natural sources for fry. But with proper planning and management, the hito farmers can produce his own supply of frees.

The size of the ponds depends on your available capital. The minimum size is 50 square meter (sq m) and should be located in low and flat areas. Land where pesticides have been regularly used should be avoided. Choose a shady area so that fish will have shade when the sun is intense and lumot or moss will grow easily. The area should also have a good supply of water either from wells, spring or run-off ponds.

There are two ways to prepare your ponds. The dug-out excavated type is made by digging the soil of the desired area at least one to one-and-a-half (1 1/2) meters (m) deep. The soil removed is used to build perimeter dikes 2 m high from the base to the top. The inner sides of the ponds is made firm by pressing with a heavy log or board. This will prevent the catfish from climbing or burrowing through the sides. A water pipe, 7.62 centimeters (cm) in diameter should be installed in the middle of the ponds so water can run through it slowly. This aerates the pond water and discourages the catfish from digging and stirring the pond bottom.

The dug-out concrete type also follows the same principle, except that the walling is made of 10 cm x 20 cm x 41 x cm concrete hallow blocks. The bottom is covered with a 15 cm-thick layer of clay soil and planted with aquatic plants like tapo grass, water lily, or kangkong to create the natural habitat for the fish.

Stocking rate. The extremely heavy stocking method produces a minimum poundage of fish per unit area. Catfish farming produces 2 crops a year at an average rearing period of 5 to 6 months. It is best to stock in the late afternoon or early morning when it is cool.

The stocking rate depends on size of fish and depth of water. (See figures below.)

Size of fish #of Fish stock/sqm surface period (months)3 to 4 cm 60 pcs/kg 80 to 100 5 to 65 to 6 cm 50 pcs/kg 60 to 80 4 to 57 to 10 cm 30 pcs/kg 40 to 60 3 to 4

Catfish are carnivorous so their feed is 90 per cent meat or other protein sources. These can be ground fresh trash fish , worms, insects, slaughterhouse by-products, chicken entrails, dried or fresh water shrimp, fish of fall and by-products of canning factories. The remaining 10 per cent is composed of boiled broken rice mixed with vegetables or rice bran. To augment food supply, install strong light over pond to attract insects.

Feed the catfish twice a day. To avoid waste, give the feeds slowly, by handful, until the fish stop eating. Daily feed ration is 6-7 per cent of the fish stock's body weight. If the fish remains small after giving them the necessary feed, provide them with 30 kilograms of farmyard manure. Add 5 to 10 per cent carbohydrates in the feed to enhance the stock growth rate. Trash feed should be fresh to maintain the nutritive value. Never overfeed since the excess would only pollute the water causing death or stunted growth.

Mating and spawning. Female catfish ready to spawn or to produce offspring builds its nest of debris or roots of aquatic plants like water hyacinths, kangkong, or filamentous algae. It spawns in shallow water, 30 cm to 60 cm deep.

Males and females ready to make frequent the nest area. Courting starts by chasing each other, darting sideways, pressing their abdominal regions together. This constantly movement is repeated several times until the females releases the eggs and male milt or sperms is simultaneously ejaculated. Fertilizer takes place at 27o to 30oC water temperature.

The number of eggs laid range from a few hundreds to several thousands.

Never scrimp on feeds especially during this period, remember that catfish are cannibalistic and quarrelsome. If the parent fish are very hungry, they may gobble up the young as quickly as any other food that come their way.

One drawback that discourages people from catfish farming is the lack of fingerlings. The following process will assure you a continuous supply of fingerlings.

There two methods effecting spawning by hormone injection. Both methods use the most gravid or pregnant females and healthy. mature males, each weighing at least 200 grams (g).

The body of the pregnant hito is distended prominently, the genital part pinkies, and the blood vessels on its belly prominent. Breeders should be conditioned first in the concrete or semi-concrete tanks/vats 2 to 5 months before they are injected with hormone.

The natural method entails injecting hormones to gravid females and male catfish through their coal regions or bases located on the posterior side of the pelvic fin. Use commercial hormone preparation like gonadotropin or synahorin. If these preparations are not available, use fresh of fish. Each female hito should be receive 200 to 250 IU (international units) of gonadotropin, while each male, 50 IU. Wrap fish in a small net so they will not struggle during injection. After injection, put the male and female together in an oxygenated tank provided with an improvised fish nest made of cabo negro(blank palm fibers).

The stripping method requires several male catfish milters to be killed. Use forceps to remove their testes which is pinkish yellow and soak in Ringer's solution. Extract sperm

by macerating the testes in the distilled water. Use sperm to fertilize breeder's eggs. Inject hormone (mentioned earlier) into the gravidbreeder's body. Inject at the side of the fish's body, a little above lateral line, with this dosage: gonadotropin = 750 to 1,500 IU; synahorin = 1,000 to 1,500 IU. After 12 hours, squeeze the breeder's abdomen to force the eggs out. A 250-gram breeder produces 8,000 to 15,000 eggs. Mix eggs with sperm and stir for a minute. Spread eggs thinly over hatching troughs which are immersed in running water with a temperature of 26o to 36oC. Eggs hatch 24 to 36 hours later.

Transfer the hatch larvae in basins half-filled with water. The young fish will absorb all the egg yolk in 5 days. After this period, they will begin to swim active and take food.

You can rear 15,000 to 20,000 frys in a space of 1 x 3 x 6 m. Minute organisms are the best food for the fry at the early stage. Twenty thousand (20,000) fry needs 20,000 liters (1) of zooplankton every morning plus a kilo of fish flesh and 250 g of peanut cake in the afternoon. After one week, fry should have grown to 1.5-4.3 cm long.

Pond-raised catfish are usually attacked by bacterial diseases. Aeromonas spp. is characterized by distended abdomen filled with opaque or bloody fluid, red spots on the body, stomach filled with yellow mucus, swollen kidneys, eroded fins, inflamed mouth, pale or green liver and excess secret of mucus. When catfish lose their equilibrium, are pale, their abdominal area tight with a distended anterior, and their peritoneal cavity filled with bloody excretion , they are suffering from pseudomonas spp. The usual sources are diseased fishes and frogs. Therefore, preventive measure must be taken during transporting and before stocking the fish. One method is to add penicillin and streptomycin to the water at the rate of 10 to 50 milligrams of per liter.

Harvesting. The rearing period depends upon the size of fingerlings stocked. Seven to ten cm fingerlings culture period lasts about 4 months while 3 to 4 cm fingerlings need 6 months. When the fish are about 20 to 25 cm long you can start harvesting, partially or completely. Drain pond partially and captured fish by seines (net hung vertically, one side with floats, other side with sinkers) or scoop nets as soon as water level is low enough. To harvest completely, let the water out through the drain pipe.

Storage and transport. The quality of fish depends on handling from the time it is caught until it reaches the consumer. Wash fish to remove mud, debris, or any foreign substance, sort them according to size and separate those which are bruised decomposed or damaged.

Remove harvested catfish from water immediately after catch and place in wood, plastic aluminum, or styroform containers. Be sure that the containers have perforated covers to prevent hito from escaping.

Catfish are equipped with special assessor organs which enable them to survive out of water for a long time. There are no rules to be followed in storing an d transporting hito because of their innate hardiness. Fill three-fourth of the container with 20 to 25 cm long catfish and four a liter of plain water. This moisture level will enable them to withstand

the rigors of travel up to 12 hours. By following this, the harvest will reach markets in tip-top condition where they are sold live. This manner of transport is also used for foreign destinations.

Market information. Catfish are commonly farmed in region 1 and 2. Raisers sell them at P21.63 per kilo (data from Market Assistance Section of Fishery Economics and Information Division), each kilo being equivalent to 5 to 6 pieces of 20 top 25 cm long hito.

This black delicious fish is sold in almost all parts of the country at an average price of P26.46 per kilo. Hito is customarily marketed through middlemen who sell at P24.28 (average cost) a kilo to retailers.

If intend to supply the local market, it is best to breed Clarias macrocephalus. Its more intense, "fishy" taste is preferred by local consumers. But if you plan to export, breed the longer bodies

Clarias batrachus or Bangkok hito. Its milder taste but firmer meat is favored by the foreign market. We exported 776,134 kg of catfish worth P29,553,813 to 13 country in 1986. The three major importers were the U.S.A., Singapore, and Canada. There is much potential in developing the British, Australian, and Taiwanese markets.

In assessing the profitability of catfish farming, you must first consider your inputs. You will need ponds, deep well, water pump, water control structures, purchase of starter fingerlings and feeds. A one-hectare hito pond usually yields 100 metric tons or 95,000 pieces of fish. If there are 6 pieces per kilo, the gross sales would add up to P341,993 if you sell at P21.60 per kilo giving you roughly 30 per cent profit.

RAISING TIPS

Don’t over stock

Catfish can be stocked at 1500 fish per surface acre for non-commercial ponds. A pond stocked at 1500 fish per acre could produce about 1500 pounds of catfish ready at one time! That’s a lot of catfish!

Feed like hogs

Catfish convert feed at an average yield of about 1 pound of fish for every 2 pounds of feed. Feed them like hogs. If you have the time feed twice a day. Keep their gut full. Feed them as much as they can consume in 15 to 30 min. Do not over feed. Feed is money. Feed the fish in the morning around 8 a.m. At this time dissolved oxygen levels have started to rise and no later than mid afternoon around 3 P.M. to allow for digestion during periods of low oxygen. Use floating catfish feed. This type of feed remains at the surface for considerable periods of time and is not subjectto loss in mud on the bottom as is sinking feed. Sinking feeds represent a small

percentage of feed fed to catfish. Feed consumption by catfish is directly related to water temperature. A 32 percent protein floating feed is fed to large fingerlings to harvest (six inches an up). As the water temperature drops, consumption declines. Feeding is inconsistent below about 70 °F and, although catfish feed at temperatures as low as 50 °F, consumption is greatly reduced.

Don’t stock catfish with other fish

It is very important to keep all bream out of your catfish pond. This will save you money on your feed bill and it could prevent low oxygen problems. If you want to have a good catfish pond, stock only with catfish. A pond produces only so much oxygen for your fish.

Use Common Sense

Catfish will eat like hogs. When catfish get sick they stop feeding. If they stop or slow down something is wrong. Think Diseases! There can be a lot of other things wrong but diseases can kill a lot of fish quick. If in doubt seek help quick. Diseases and parasites are numerous and complicated. There are no quick explanations about diseases. A fish biologist spends years studying diseases.

How to train your fish on feed

Catfish will take man made feed very easy. Place a flowing ring in the pond big enough to hold your feed. This ring can be made out pvc or wood or any thing that floats. This allows your feed to stay in one place ( keeps the wind from blowing the feed on the bank ) your fish can find the feed and know where to go to feed. Place this ring in at less 3 feet of water. Once your fish start to feed, this ring can be removed.

The don't list

* Don't fertilize a catfish pond.* Don't over feed.* Don't let your catfish reproduce in your pond.* Don't raise catfish and bream together.

Training and seminars:Bureau of Fisheries (BFAR)Arcadia Building860 Quezon Avenue1103 Quezon City, PhilippinesTel No. : +63(2)3725043Fax No. : +63(2)3725048Email : info@bfar.da.gov.ph

Raising Catfish

Contributor By G. K. BayneeHow Contributing Writer Article Rating: (3 Ratings)

Fishermen can raise catfish as a hobby or to put extra food on the table. Catfish are hearty and can be grown to eating size in less than a year. In a pond, catfish have few predators and will eat anything from small bait fish to algae. Stocking a pond is simple and only takes a bit of planning.

Things You'll Need: Catfish fingerlings Pond Catfish food 1. Step 1

Determine if your pond is deep enough to raise catfish to maturity. The perfect pond is around 4 feet deep, but they can be raised in as shallow as 2 feet and as deep as 6 to 10 feet. The deeper the pond, the harder it will be to harvest the fish.

2. Step 2Contact your local feed stores or county extension agent to find out where to purchase catfish fingerlings. These fish are usually 4 to 6 inches long and are purchased in groups of 50 or more fish to the bag. Most feed stores have "fish stocking days" in which several varieties of fingerling fish are offered for sale.

3. Step 3Place the unopened bag of fish into the pond to give them a chance to acclimate to the difference in water temperature in the bag, as compared to the pond water. Leave the bag unopened for several hours to overnight.

4. Step 4Release the fingerlings into the pond. Sprinkle a high-protein catfish food on top of the water. Read the bag to determine how much food to feed for the number of catfish you have purchased.

5. Step 5Fish the pond using catfish or other bait monthly to determine fish growth. The fish should begin to reach a small, edible size in approximately 6 months.

6. Step 6Harvest the fish by either fishing or by throwing a seine in the water when the fish have reached the desired size. Clean and process the fish immediately after harvest.

Tips & Warnings Most catfish foods are medicated to prevent diseases common to the catfish

species.

Catfish can live for many years and reach 20 pounds or more in an average pond.

Hito (Catfish) Raising

If you want to know tips and procedure how to culture Catfish or Hito, then this is the post your looking for.

Hito can be raised in a small pond. There are two common varieties of catfish in the Philippines—one that is our own native hito that thrives in rice fields and rivers, sometimes in muddy places; and the other one brought over from Thailand or Taiwan. Both kinds can be raised and grown commercially.

Within four months, hito can grow as big as a size weighing 300-400 grams or three in a kilo. In Taiwan, they grow hito as big as two kilos each.

Hito from Taiwan origin is dark gray with white belly.

Cage

1. For commercial purposes, one hectare of fish pond can rear as many as 100,000 small hito or fingerlings. In other countries like Thailand, they grow as many as 300,000 to 400,000 fingerlings in one hectare of fish pond.

2. The sides of the fishpond should be concrete so as to withstand flood or heavy rains. The smaller the grow-out ponds, the easier to manager them. (1 ½ hectare)

3. It is not necessary to provide an aerator even if the fish population is big because the

hito has an auxiliary respiratory organ and can naturally breathe fresh air; therefore it is not stressed by low dissolved oxygen levels.

4. The ponds water depth must be about one and half meters ( ½ m) throughout the culture period. fresh water may be drawn from a nearby river. Change of water is done when it becomes murky.

Feed

Hito needs protein, so they like flesh meat. They can also thrive on any food growing in the pond bottom, or they can eat one another, or escape from the pond. So, they must be provided with enough protein foods—carcass, trash fish, commercial fish feed.Some hito growers get their carcass feed from chicken or poultry internal organs, or trash fish from fishermen.

It takes four months to grow hito that is about 2 kilograms, or three-to-four-pieces per kilo.Source: Greenfields, August 1991; http://elgu2.ncc.gov.ph; photo from:advanceddivermagazine.com

Workbook

work·book  (wûrk b k )n.1. A booklet containing problems and exercises that a student may work directly on the pages.2. A manual containing operating instructions, as for an appliance or machine.3. A book in which a record is kept of work proposed or accomplished.workbook [ˈwɜːkˌbʊk]n1. (Social Science / Education) an exercise book or textbook used for study, esp a textbook with spaces for answers2. (Communication Arts / Printing, Lithography & Bookbinding) a book of instructions for some process3. (Communication Arts / Printing, Lithography & Bookbinding) a book in which is recorded all work done or plannedworkbook - a student's book or booklet containing problems with spaces for solving thembook - a written work or composition that has been published (printed on pages bound together); "I am reading a good book on economics"

Manual Of or pertaining to the hand; done or made by the hand; as, manual labor; the king's sign manual. A small book, such as may be carried in the hand, or conveniently handled; a handbook; specifically, the service book of the Roman Catholic Church. A keyboard of an organ or harmonium for the fingers, as distinguished from the pedals; a clavier, or set of keys.

A prescribed exercise in the systematic handing of a weapon; as, the manual of arms; the manual of the sword; the manual of the piece (cannon, mortar, etc.).

textbook definition text·book (tekst′bo̵ok′)nouna book giving instructions in the principles of a subject of study, specif. one used as the basis or partial basis of a course of studyadjectiveso typical as to be suitable for inclusion in a textbook; providing a model; classic a textbook case of medical malpracticeDefinitionsnoun textbook

1. a formal manual of instruction in a specific subject, especially one for use in schools

or colleges.

Translations:  Dutch: studieboek French: livre de classe German: Lehrbuch Italian: libro di testo Spanish: libro de texto

adjective 1. of or pertaining to textbooks or their styles.

examples 1. dealing with a subject in a pragmatic or fundamental way, as books or

persons do.

a approach to introductory psychology 1. having the typical characteristics of some class of phenomenon.

a case of mistaken identity