Snakehead (Channa striatus) Farming in Thailand
	CONTENTS

Kok Leong Wee

Institute of Aquaculture
University of Stirling
Stirling FK9 4LA, Scotland
United Kingdom

NETWORK OF AQUACULTURE CENTRES IN ASIA
Bangkok, Thailand
November 1981

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FOREWORD

This report presents the results of a study undertaken in Thailand during 22 February to 22 March 1981. The objective was to survey snakehead farming practices in the country. Due to logistical constraints, however, it was only possible to concentrate on four snakehead farms. My report is thus a general description of snakehead farming based on primary data obtained from the four farms close to Bangkok and on other information obtained from reports and discussion with Thai fisheries workers.

CONTENTS

FOREWORD

1. INTRODUCTION

2. PARTICIPANTS

3. FARM DESIGN

4. PREPARATION OF PONDS

5. SEED FISH SUPPLY

6. STOCKING PROCEDURES

7. FEEDING

8. PRODUCTION

9. MARKETING

10. PROFIT MARGIN

11. DISEASE

12. PRIMARY DATA

13. DISCUSSION

14. ACKNOWLEDGEMENT

15. REFERENCES

LIST OF FIGURES:

1. Example layouts of snakehead farms in Thailand

2. Incidences of mortality in the 1980 production cycle of a Channa striatus crop, Thailand

List of Tables:

1. Market prices of Channa striatus in 1980

2. Marketing margin of the sale of Channa striatus based on primary data

3. Primary data on the culture of snakehead in four farms, Thailand

SNAKEHEAD (Channa striatus) FARMING IN THAILAND

Kok Leong Wee¹

1. INTRODUCTION

Aquaculture has been practised in Thailand for many years. It is, however, only in the last few years that it has undergone rapid advancement. The principal reasons for the increased interest and development of fish farming are due to the recent advances in the development of culture techniques in the world particularly in the field of husbandry and management of culture system and the development of standardised artificial breeding technologies such that the supply of seeds are guaranteed and controlled by the fish farmers themselves. Also important are the efforts of the Thai Government in promoting and aiding the aquaculture programmes. Farmers are now presented with alternatives of turning their rice fields and wasteland, such as swamps and ditches, into fish ponds. Fishermen and trawlermen, unemployed as a result of the overfishing of the stocks in the Gulf of Thailand, are encouraged to turn to aquaculture as a means of reducing unemployment and as part of the national development programme.

The rapid growth and the expansion of the fish farming industry has severely taxed the ability of the Department of Fisheries to maintain an account of all fish farming activities. This is not helped by the fact that most small scale fisheries do not keep any form of record of their operations. Consequently exact data on the present events of the smaller scale fisheries are limited. The present position statement, given below, is based on the estimates projected from records recently completed on 1975–76 data and adjusted by the opinion of DOF² personnel who have daily contacts with aquaculture (Plodprasop Suraswadi, 1980). These estimates indicate that more than 20 species (including Macrobrachium sp.) are being cultivated in freshwater, yielding an annual production of 47,850 metric tonnes of which 95% is contributed by 10 species. The value of this production, based on farm gate prices, was around US$ 43.5 million/year. There are some 20,000 ponds with a total area of 6,000 ha, about 51,000 paddy fish farms with an area of 35,000 ha and an undetermined number of small back yard ponds. There are also some 450 ditch culture operations and 600 cage culture operations.

¹ Ph.D., candidate, Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, Scotland.

² Department of Fisheries, Ministry of Agriculture and Co-operatives, Bangkok, Thailand.

Aquaculture in Thailand is very diverse. As indicated above, there are about 20 species of fish being reared. Fish are cultivated in converted paddy fields, dammed-up ditches, swampy areas and in cages and there are numerous types of systems that are in use. These systems vary from the very intensive farms with precise controls on the input stock, feed and water and harvest, which are operated by big business concerns for commercial production, to extensive systems where brood stock are introduced into a defined area of water and the resulting brood are allowed to grow on without any supplementary feeding or management, operated by farmers mainly for home consumption. In between these two extremes, can be found farms where the feed is supplemented totally and some farms where the feed is partly supplemented and partly provided through production of food organisms in the water through fertilisation. Generally, most of the fish farms are run on monoculture lines, although there are polyculture systems and some where wild fish are introduced and harvested together with the cultured species. Some farms are integrated with the production of other crops such as livestock, pigs and poultry. Edwards (1980), reported a very large integrated farm utilising several thousand chickens, ducks, pigs and one million fish. The main idea is to utilise and recycle the animal wastes. The chicken coops are built over the pigs pens in the nearly one km² feedlot so that the chicken droppings supplement the pig feed. The pig manure is collected and used to raise Pangasius catfish which receive no other feed input. Even dead pigs are recycled since they are cooked using biogas generated from pig manure and then fed to Clarias catfish.

Snakehead have long been regarded as a valuable food fish by the Asian people. In Thailand it is one of the most common staple food fishes. In the past most of the supply of snakehead came from capture fisheries. In recent years, however, declines in the harvests of wild snakehead, due to overfishing and the destruction of sprawning areas with pollution from industrialisation, along with the suitability of the fish for culture by virtue of its air breathing characteristic and hardiness, have created keen interest in farming the species. There are several species of snakehead belonging to the genus Channa in Thailand, but only one species is cultivated, the species Channa striatus (=Ophicephalus striatus).

Until a few years ago, Clarias catfish (C. batrachus and C. macrocephalus) was preferred to C. striatus for culture because of the shorter raising period - six months for Clarias catfish as opposed to seven to nine months for C. striatus. The longer raising period means a higher capital out-put as the feed cost can be as high as 70% or more of the total operating cost. However, interest is now moving towards C. striatus for various reasons. The main reason is that of the difficulties now facing Clarias farmers owing to disease, husbandry and management problems; recent overproduction also resulted in depressed prices rendering Clarias culture less profitable than previously. Consequently, some of the Clarias farmers have converted to snakehead farming which has expanded considerably in the last five years. All four of the farms visited during the present study were only three to four years old.

2. PARTICIPANTS

Generally, C. striatus is cultured in monoculture systems. There are very few farms that utilise C. striatus in polyculture systems. Snakehead is cultured by people with access to capital who normally farm other species such as Pangasius catfish, Clarias and Chinese carps but realising the potential of C. striatus, and have allocated a few ponds for it. Snakehead is also cultured by small family concerns owning one to three ponds. The operations of the smaller farms are restricted by the very high capital requirement largely due to the high feed costs. Capital for each crop is often obtained through loans from fish wholesalers and the loan is repaid after harvest. By this means, wholesalers maintain control over most of the smaller scale farms and fix the price of purchase during harvest.

3. FARM DESIGN

Generally the farms have a similar type of layout. Most obtain water by pumping from a khlong (canal) or a ditch, more or less continuously; some farms pump water for twenty four hours a day, others for up to ten hours a day. Some of the farms pump the water directly into ponds while others pump water from the khlong into a ditch and make use of a gravity flow system to all the other ponds. Only one farm had ponds where there was no water exchange, this farm had larger ponds, than the usual. Normally ponds ranged from 800 – 1,600 square metres (0.5 – 1.0 rai), but in this case they were two rai in area. The smaller size ponds are favoured by the farmers as the culture operation is very intensive and the smaller size facilitates easier management and feeding operations and especially, facilitates harvesting. The depth of the ponds is usually between 1.5 – 2 metres. The different types of system and farm layout is presented in Figure 1.

4. PREPARATION OF PONDS

In between two successive crops an interval of two - three months is used to repair and prepare the ponds for stocking. Ponds are drained dry at the last day of harvest. The bottom mud and detritus are dug up and the bottom is then lined with sand. The pond is then left to dry for fifteen days. Water is then run in and left standing for three days, after which it is drained off. The pond is now ready for stocking.

Palurak Farm

Figure 1: Example layouts of snakehead farms in Thailand.

5. SPEED FISH SUPPLY

The supply of seed fry is available throughout the year but the peak availability is during the wet season from May to September/ October. The planning strategy used by farmers in order to maximise their profits requires them to harvest their crop around April/May. Thus the peak in demand for fry stocking is in the months of July/ August. All of the farms obtain their fry for stocking from specialist fry collectors. These collectors, using their knowledge of the natural spawning grounds, collect wild fry using simple netting procedures. The fry are collected as ordered and as such some orders may take several days to complete. Most of the farmers stock their ponds using fry of more than 10 days of age and about 1 – 2 cm in size. Very few farmers stock their ponds with fingerling size as such, since there are no specialist fingerling producers. There is some artificial spawning of C. striatus carried out by the DOF personnel in research institutions around the country. The brood stock were provided with as near natural conditions as possible. They are usually placed in ponds with muddy bottoms and in very shallow waters of between 30 – 100 cm deep. Aquatic vegetation is introduced, (usually water hyacinth) and fish placed in such ponds normally spawn in one to two months time.

Snakehead fry are sold in three forms:

1. By weight

   Price ranges from 70 – 80฿/kg (U.S.$1.40 – 1.60). (I was unable to estimate the number of fry in one kilogram).

2. By ‘cup’

   Price ranges from 12 – 15฿/cup (U.S.$0.60 – 0.75). (Each cup contain 300 – 400 fish fry).

3. By numbers

   Price ranges from 3 – 7฿/100 (U.S.$0.15 – 0.35) for 2 cm fish and 7 – 12฿/100 (U.S.$0.35 – 0.60) for 3 – 5 cm fish.

6. STOCKING PROCEDURES

In order to obtain the maximum profit for their crop, farmers stock their ponds in the months of July and August so that they can harvest their crop in the months of April and May of the next year which is the end of the dry and beginning of the wet season. This is because at this time the catches from the wild are low since the temporary fisherman, rice planters who are supplementing their income with fishing while waiting for the wet season to start preparing and planting the rice, have gone back to the fields. The price of snakehead is at this time highest for the year. It is only logical therefore that farmers plan their production such that they get the maximum profit margin by cropping at this time.

The stocking rates are extremely variable, ranging from 75/m² to 460/m². These figures represent a relatively high stocking density. Most of the farmers have the rather unscientific belief, extant in fish farmers the world over, that since they expect a high rate of mortality, they should stock at very high rates hoping that the higher numbers of fry will compensate for the high mortality rates. Such a high stocking rate only wastes the resources and incurs a higher feed bill when fish start to die after a few weeks of culture. The fry are placed directly into the production ponds without going through any nursery facility and are grown on in the same ponds to harvest.

7. FEEDING

The fry are fed on finely chopped trash fish. This is fed ad lib and the feeding rate adjusted by observing the behaviour of the fish during feeding. Normally it is the practice to overfeed and recover the uneaten feed which floats up after several hours. The next day's feeding rate is then adjusted accordingly. There is no sampling of the stock to determine the exact amount of feed consumed. The fish are fed three times a day from the fry to fingerling stage, twice a day from fingerling stage and finally once a day. The period at which the frequency of feeding is changed is arbitrarily determined. From fingerling size, the fish are fed a combination of trash fish and rice bran and in some farms broken rice is also included. In smaller backyard ponds vegetable and kitchen wastes are also used as feed. The ratio of the combination of trash fish to rice bran ranges from 8:1 to 13:1 depending on the availability of trash fish. The trash fish food is normally delivered to the farms but if the farmer has a vehicle and can thus collect his supply of trash fish from the ports, he has the benefit of selecting better quality trash fish, in terms of the freshness. The supply of trash fish is normally available all the year round. There are however times when the weather gets too bad for the trawlers to go to sea and then trash fish will be unavailable. In such circumstances the fish were not fed until it is again available.

The trash fish and the rice bran are mixed and put through an extruder, forming strands. The strands are then either dropped into the ponds or placed on wooden platforms which sink with the weight of the feed. These platforms are placed all round the ponds. Some farmers added mineral and vitamin supplement to the feed. The average food conversion rate obtained from one farmer who kept records of input and output was about 6.5:1. It is reasonable to assume that other snakehead farmers also obtain such values for their food conversion rates, as they all use more or less the same management techniques.

None of the snakehead farmers use artificial pelleted diets. There are pelleted feeds for Clarias catfish and Macrobrachium but none that is specifically formulated for snakehead.

8. PRODUCTION

The raising period ranges from 7 to 10 months depending on the types of system, the stocking densities and the feed used. The fish at harvesting time weigh between 700 – 1,000 gm, that being the accepted market size. Actual harvesting time depends on the prevailing supply of market size snakehead from the wild and the market price. However if the catches from the wild are still abundant at the end of the production time, the farmer may choose to maintain the crop until the market price is favourable. This course of action may not however be economical, as the feed bill can be substantial and the demand for large size fish of over 1 kilogram is very poor, as it is then quite expensive for the average consumer. Alternatively, the farmer may harvest his crop and accept a lower profit margin or even a slight loss in order to recover the capital. The crops are harvested using seine netting over 4 – 5 days. On the last day, the pond is drained dry. The whole crop is harvested, there is no multiple cropping and the entire operation from the netting to transportation to the market is handled by the fish wholesaler.

Production ranges from 15 – 25 tonnes per rai (9 – 15.6 kg/m²).

9. MARKETING

Snakehead are sold by weight, with grading, to the wholesalers. There is only one ‘pure’ fish market in Thailand, where freshwater and marine fish are auctioned for Bangkok. This is run by the Fish Marketing Organisation (FMO) at Yanawa, Bangkok. There are four registered fish wholesalers for freshwater fisheries, these are known as Pae Pla and they charge 6% of the total value of the fish sold from producers. The Pae Pla in turn pays 1% of total value of fish sold to FMO which provide marketing facilities.

Snakehead sales are generally handled by Bangkok wholesalers. For example, in the province of Pathumthani, the production from six snakehead farms was handled by one Bangkok wholesaler (Edwards, personal communication).

The price of fish in Thailand is determined both by individual negotiation and trading on organised auction. In theory, fish auction at FMO is based on Government regulation but in practice it is individual trading overall i.e. prices are generally determined by demand and supply and the amount of price cutting between farmers.

Channa striatus is always sold live, since the price is reduced by 30 – 40% when dead. Processed fish (i.e. salted, dried) command only 40 – 50% of the price of live fish. Fish too stale for processing into salted or dried form were processed by fermentation and sold for around 20% of the price of live fish.

10. PROFIT MARGIN

Marketing margin, defined as the difference between the wholesale price and the retail price, for C. striatus, was 16, 15.50, 15฿kg in August, September and October 1980 averaging 32.9% with respect to the wholesale price.

This is about twice as much as the market margin for Clarias catfish (18.7%). Table 1 shows the wholesale and retail price of C. striatus during 1980.

Table 1: Market prices of Channa striatus in 1980.

1 ฿ = US$ 0.0476 = ₤ Stg. 0.02173
¹ FMO Statistics 1980.
² Department of Domestic Trade Statistics 1980.

Using primary data calculated from field visits to farms and markets (Edwards, personal communication), the marketing margins can be broken down as shown in Table 2.

Table 2: Marketing margin of the sale of Channa striatus based on primary data. (Edwards, personal communication).

1 ฿ = US$ 0.0476

11. DISEASE

The farms reported that major mortalities occured in every production cycle. Farmers, however, did not know the cause of these deaths. The dead fish were simply recovered and thrown away in rubbish dumps or used as manure on vegetable plots. None of the diseased fish were sent for diagnosis and thus there are no known diseases of cultured snakehead other than reports on their ectoparasites and internal parasites.

In one of the farms visited, Palurak Farm, which kept mortality records, it would appear that there are two major peaks of observed mortality (Figure 2). The first occurs between the 60 and 70 days of culture and the other occurs between 230 and 250 days of culture.

Any outbreak of disease in the farms is countered with the universal treatment of antibiotics regardless of whether this is justifiable on clinical grounds or not. The antibiotics are incorporated into the feeds at a rate of 2 kg of antibiotics in 850 kg of trash fish mixed with 35 kg of rice bran. One farm reported incorporating 2 kg of antibiotics in the feed for 200,000 fish (size of fish was not given). Other farmers try local treatments using various herbs prepared by the farmers themselves. The efficiency of these local remedies has not been evaluated.

Disease is obviously a major limiting factor with snakehead farming but there has been no concerted effort to tackle the problem and all that the snakehead farmers can do at the moment is to continue using antibiotics on an ad hoc basis.

12. PRIMARY DATA

A summary of the primary data gathered from the visits to the four farms around Bangkok is presented in Table 3.

13. DISCUSSION

One of the most significant limiting factors restricting the expansion of Channa striatus culture is the extremely high cost of feed. Being trash fish, its supply is irregular and unreliable; for example in one of the farms, in 260 days of culture, there were at least 12 days of supply failure when the snakehead crop was not fed. There were even instances where periods of failure of trash fish supply forced farmers to either face the consequences of not feeding the fish or to feed the crop with expensive commercial fish such as mackerel as one farmer had done. The nutritive value of the trash fish may not be consistent and in some cases the trash fish may have already gone bad even before delivery owing to the lack of refrigeration and the high air temperature accelerating the decomposition.

Figure 2: Incidences of mortality in the 1980 production cycle of a Channa striatus crop, Thailand.

Table 3: Primary data on the culture of snakehead in four farms, Thailand.

The fish farming industry, which utilises trash fish, is now experiencing very intense competition from the fish meal producing industry. At present there are 79 fish meal factories registered with the DOF, having a total capacity of 280,000 tons/day. The fish meal produced is for export and for domestic use as animal feed. This competition has led to increases in the price of trash fish. This is evident from the records of trash fish prices at FMO at Samut Sakhon, a port south of Bangkok. The average price of trash fish in 1969 was 0.65 ฿/kg, rising to 1.03 ฿/kg in 1975. In 1980 the price was 2.19 ฿/kg. These are wholesale prices listed by the FMO; by the time the trash fish reaches the fish farms, it would have cost an additional 1 ฿/kg. The problem is now aggravated by the overfishing of the fish stocks in the Gulf of Thailand resulting in low catch yield forcing the trawlers further out to sea for a reasonable catch, thus adding to the cost.

Most of the problems associated with the feeding with trash fish can be solved by changing to feeding with pelleted diets. The development and the progress of the catfish (Ictalurus) industry in the U.S.A., and the trout and salmon farming industry in the Europe and North America had been aided by the development of suitable pelleted diets. Advantages in using artificial pelleted feed include a continuous availability and uniformity of food, ease of transport and storage, ease of feeding controlled rations, water stability of the pellet (implying minimal loss by leaching) and maintenance of water quality and reduction in the risks of transmitting disease by feeding of wild trash fish to hatchery fish.

Pelleted diets, however, contain quite a high proportion of fish meal as the source of protein. As the price of the fish meal is quite high and increasing with time, the price of the pelleted feed tends to be more expensive than trash fish. The 1980 price of pelleted feed is 7 – 8 ฿/kg. In Thailand there are three fish feed producers whose main interests are producing feeds for the poultry, cattle and ornamental fish but who are now branching out to producing pelleted feed for culture fisheries. Two of the producers produce the sinking pellet suitable for the catfish Clarias and Macrobrachium. The other producer manufactures floating feed. There is no pelleted feed that is specifically formulated for snakehead. Efforts are being made by the fish feed manufacturers to encourage the snakehead farmers to change to using artificial pelleted diets, citing less wastage and better food conversion rate. The production and the growth of snakehead fed pelleted foods have not been evaluated and their nutritional requirements are still being investigated. When their nutritional requirements are known and can be provided in the artificial pelleted feed, the snakehead farming industry may then be developed to its fullest potential.

Stocking rates are not standardised and at present tend to be relatively high. Information on suitable stocking rates has been passed from one farmer to another by word-of-mouth. There has never been an effort by the farmers themselves to find out the optimum stocking density for their farms. The very high stocking densities used have led to very high levels of stress due to overcrowding, which increases the incidence of disease and mortalities as evident from the mortality data presented earlier. The high stocking density also leads to a stunting problem and a hierarchy based on size will almost certainly be set up, resulting variation in size and growth rate. From primary data, it would appear that the maximum yield is about 25,000 kg/rai (153 tonnes/ha) which may be the capacity of the 1 rai pond to hold such a weight of fish without being overloaded. Already there are indications that the maximum capacity of the pond is being reached around 250 days as evidenced by the observed mortalities data which showed that during later stages of the raising period, around 230 to 250 days of culture, there is a peak of mortalities which may be attributed to the deteriorating water quality as a result of the heavy biomass in the pond and smaller fish attacked by the bigger dominant fish.

The feeding techniques used in the industry obviously need to be revised. There should be a controlled feeding frequency and feeding rate. Research should be carried out and results tested in the field. At present, the feeding techniques employed are wastedful, but the unreliability of the supply of trash fish may present problems even if the farmer does have a fixed feeding rate.

With the development and progress of the snakehead farming industry, there will no doubt be more people venturing into the business leading to overcrowding of farms in favourable areas. This will, as in the case of the catfish industry, lead to pollution and ready transmission of disease from farm to farm. In this respect, more attention should be placed on the problem of outbreaks of disease, since it is essential to obtain a disease list and treatment programme for the industry similar to that now available at NIFI ¹ for the catfish industry.

The problem of the supply of seed also needs to be looked at closely. At present the supply of seed is still adequate. There are, however, signs that seed stock is becoming progressively more difficult to secure. This problem will become more acute as the industry expands and more fry are required. More importantly when all of the technical and management problems have been solved and techniques of culture improved to such an extent that farmers have reached the maximum capacity that an area of water can maintain, the only means of improving production is through genetics i.e., through genetical selection of desirable traits, such as better growth performance, disease resistance and hybridisation. This can be achieved only when the techniques for artificial propagation have been standardised and refined.

¹ National Inland Fisheries Institutes.

In conclusion, one has to admire and wonder at the state of snakehead culture and aquaculture in general in Thailand and the rate at which it has developed and progressed especially when we consider that most of the technical and management problems have been solved using local resources with a great deal of ingenuity and imagination. This is even more remarkable when we realise that Thailand does not have any fossil fuel resources, which have to be imported and yet some of the fish farming and fisheries are very energy intensive, for example, the feeding of trash fish in Clarias and Channa striatus fish farms and the continuous pumping of water from the khlong. It can be said that Clarias and Channa striatus culture have flourished as the trawling industry has expanded. Unless the trash fish can be replaced by some equally good alternative feed, Clarias and Channa striatus farming is going to suffer the decline that is now facing the trawling industry.

14. ACKNOWLEDGEMENTS

This work was made possible by valuable contributions from Professor R.J. Roberts and the University of Stirling, Dr. Alex Fedoruk, FAO Project Manager for THA/75/012, Dr.P. Edwards of AIR and Mr. Chen Foo Yan of the Network of Aquaculture Centres in Asia (UNDP/FAO/RAS/76/003).

I would like to thank the above mentioned for their help and I would also like to thank Mr. Vanich Varikul and Dr. Plodprasop Suraswadi and the various scientific members of staff at NIFI for allowing me to work there and providing me with much information as a basis for the study.

15. REFERENCES

Edwards, P., 1980.
A review of recycling organic wastes into fish, with emphasis on the tropics. Aquaculture, 21: 261 – 279.

Plodprasop Suraswadi, 1980.
Freshwater fisheries of Thailand in The Third Inland Aquaculture Training Course. June 11 - July 30, 1980. Technical paper No. 4/1980 produced by National Inland Fisheries Institute Freshwater Fisheries Division, Department of Fisheries, Thailand.