C.V. Mohan
Department of Aquaculture, College of Fisheries,
Mangalore-575002, India
Mohan, C.V. 1996. Health management strategy for a rapidly developing shrimp industry: an Indian perspective. In Health Management in Asian Aquaculture. Proceedings of the Regional Export Consultation on Aquaculture Health Management in Asia and the Pacific. R.P. Subasinghe, J.R. Arthur & M. Shariff (eds.), p. 75-87. FAO Fisheries Technical Paper No. 360, Rome, FAO. 142p.
Abstract
Over the last five years, the shrimp farming industry of India has transformed from a traditional shrimp trapping system to a capital oriented semi-intensive system. Availability of large areas of suitable coastal land and the recent liberalization policy of the government encouraged investment, leading to a phenomenal growth of this industry. More than 80 000 ha of coastal land have been brought under culture, producing about 75 000 mt of shrimp in 1994. The 100% export-oriented shrimp farming industry has generated rural employment and the development of integrated industries. Since July 1994, the industry has been under the grip of disease, two epizootics of viral etiology having nearly wiped out several farms along the east coast. In spite of observing “crop holiday” and following standard disinfection procedures, the disease has reappeared in farms where trial restocking has been attempted. Ecological degradation, intensification, the import of live seed, bad water management practices, high stocking densities, natural calamities etc. are among the causes proposed for the current catastrophe. Socio-economic implications, mangrove destruction and salination of agricultural land and freshwater bodies are some of the negative impacts of the industry's unregulated and hasty expansion. India has a vast potential for shrimp farming, and the industry has enormous potential to generate much-needed foreign exchange, rural employment and the development of ancillary industries. However, to achieve sustainability, it must develop in a planned and regulated manner. Hence, effective health management strategies, guidelines and regulations are urgently needed. This paper reviews the current status of the industry, examines current disease problems and proposes practical long-term health management strategies and regulations to develop a sustainable industry.
INTRODUCTION
Traditional shrimp trapping systems have been in practice in the low-lying brackishwater areas of Kerala and West Bengal for several years. These systems are largely seasonal in nature. Autostocking aided by tides is practiced, and managerial inputs are minimal. Production from these traditional trapping systems is very low, averaging 100-500 kg/ha/crop.
India has vast potential for the development of commercial shrimp farming, being blessed with 1.2 million ha of coastal brackishwater land. Many coastal areas are rich in natural seed resources, and broodstock collection grounds are said to be ideal for commercial exploitation. The industry is basically export-oriented and has enormous potential to generate much needed foreign exchange. Short development periods, high return on investment and good international demand are positive features which should encourage the development of the industry. In addition, the industry can create significant employment in rural areas, including employment for women.
Realizing this enormous potential, the Government has identified aquaculture as a “thrust area” under “extreme focus” for augmenting exports and earning much-needed foreign exchange. To encourage shrimp farming ventures, the Government has recently implemented a series of liberalization policies. Restrictions on the importation of aquaculture machinery, feed and aqua-chemicals have been cased, and import duties on specific items like feed have been completely slashed. Steps have been taken to encourage foreign equity participation in joint ventures and full repatriation of profits by foreign collaborators has been allowed. Five-year tax exemption has been given to companies which are 100% export oriented.
PRESENT STATUS OF THE INDUSTRY
Realizing the enormous potential for investment opportunities and taking advantage of the government liberalization policy, several national and international corporate houses, private companies and individual entrepreneurs have embarked on setting-up shrimp hatcheries and farms. Nearly 80 000 ha is under extensive or semi-intensive culture, and the quantity of farmed shrimp produced in 1994 was around 75 000 metric tonnes (mt). The area being brought under culture is increasing rapidly. At present India is ranked fourth in the world in cultured shrimp production.
In the last two to three years, growth in the shrimp hatchery sector has been phenomenal. Before 1993, seed availability was a major bottleneck. With the establishment of 100 state-of-the-art hatcheries with a total capacity of 4 billion seed per annum, this problem seems to be temporarily solved. Availability of good quality feed has not been a serious problem. Most feed is currently imported. Realizing the potential demand that exists for shrimp feed, several Indian and foreign joint-venture companies have established feed mills. Aquaculture machinery and aquachemicals are being regularly imported.
Resource mobilization and financing for the development of shrimp farming have been relatively well organized, because shrimp farming is no longer seen as a traditional occupation but as a capital intensive industry. Public and private banks are extending loans to the industry on a priority basis. Several private companies have gone public and have raised sufficient funds through public issue of equity shares. Insurance companies are also involved, with risks associated with natural calamities and diseases being insured and crop losses protected.
The concept of satellite and franchise farming as promoted by big industrial houses is well established and is working reasonably well. In these systems, the industrial house acts as the nucleus for several hundred small- and medium-scale extensive farmers. Technical input in the form of consultancy and other inputs in the form of seed, feed, and disease and water quality management are provided. The end product is bought back by the company at the prevailing market price. In addition to satellite farming, many small companies have long-term buy back arrangements with big industrial houses and multinational companies.
The booming shrimp industry has encouraged the development of several small-scale aqua-related ancillary industries in rural areas and has created many employment opportunities for the rural poor. In the last three to five years, the industry has grown by leaps and bounds, but still only a small percentage of the available 1.2 million ha of suitable coastal land has been brought under culture. In this short period, the industry has come face to face with many crippling problems. The repercussions of unregulated expansion are already being felt in many quarters. The prospect of rapid development and fast returns has led to haphazard and unorganized growth and the “fast buck syndrome” has overshadowed all relevant scientific and ecological considerations. Unplanned and unregulated mushrooming of farms around available water sources has led to negative impacts, such as serious ecological degradation, socio-economic problems, social tensions, mangrove destruction, isolation of villages and salination of agricultural land and freshwater wells.
The expansion of the industry and the desire of the farmers to make quick money have encouraged pseudoconsultants and quacks. The easy availability of a large quantity of inferior quality chemicals has led to an indiscriminate use of antibacterials and other chemicals. Bacterial drug resistance (Karunasagar et al., 1994), tissue residues etc. are some of the serious problems which need to be addressed.
Aquaculture waste management has become a very serious issue. The majority of the farms use source water as a dumping ground for waste discharge. Raw effluents rich in organic matter and waste feed are released directly into water sources without any treatment or settlement. There are no community joint agreements on coordinated arrangements for water intake and effluent discharge. This has led to problems connected with disease transmission and bad water quality, and little attention is being given to pond drying, disinfection and waste removal between crops.
Crop losses due to natural calamities like flooding and cyclones have become common. Absence of buffer zones and destruction of mangroves have further aggravated these problems. Since July 1994, two viral diseases (yellowhead disease (YHD), and possibly systemic ectodermal and mesodermal baculovirus (SEMBV)) have had disastrous effects on the booming shrimp industry, causing losses estimated at around Rs 600 crores (US$ 17.6 million). Since January 1995, a fallow period, or “crop holiday”, has been observed in many farms along the east coast. In spite of observing “crop holiday” and adopting standard disinfection programs, the disease has reappeared in many of the farms where trial restocking is done. It appears that the industry will need some time before it can regain its original tempo and status.
In view of the current industry crisis, there is an urgent need to develop and execute a rational health management strategy and to frame suitable legislation and guidelines for ensuring the development of sustainable shrimp farming. The shrimp farming industry in India needs to be developed on sustainable lines because there is still vast potential for growth, and significant potential for generating foreign exchange and rural employment.
MAJOR HEALTH PROBLEMS AND THEIR CAUSES
In hatcheries, luminescent vibriosis (Vibrio harveyi, V. splendidus, V. parahaemolyticus), external fouling (protozoan ciliates like Zoothamnium and Vorticella, filamentous bacteria like Leucothrix) and larval mycosis (Lagenidium) have been consistently recognized as major health problems (Felix et al., 1994). In some hatcheries monodon baculovirus (MBV) has been identified as a problem (Felix and Devaraj, 1993; Ramasamy et al., 1995).
The majority of the pathogens encountered in hatcheries are normal components of the marine ecosystem. Opportunistic vibrios and external foulers become a serious problem in badly managed hatcheries. Excess stress, bad water quality and inefficient disinfection programs are some of the causes of hatchery problems. With regard to MBV, it is well known that most broodstock are natural carriers. MBV becomes a serious problem only in stressed hosts and in hatcheries lacking organized and efficient disinfection programs.
Prior to April 1994, Indian shrimp farms did not experience any serious disease problems. Conditions such as external fouling, shell and appendage necrosis, black gills, luminescent vibriosis, systemic vibriosis, chronic vibriosis, muscle cramp etc. were regularly reported from farms along the east and west coast. These health problems were responsible for low levels of mortality in several farms but not for mass mortalities over large areas.
Stressed shrimp tend to be sluggish and do not exhibit grooming behavior. Colonization by external foulers is very common in weak and unhealthy shrimp, and severely fouled shrimp are susceptible to opportunistic secondary invaders like vibrios. The majority of health problems in Indian shrimp farms can be traced to excess stress associated with intensification, poor water quality, pond bottom deterioration due to waste accumulation, benthic algal growth and subsequent decomposition, lack of reservoir tank facilities for carrying out suitable prophylaxsis and bad quality source water.
THE CURRENT CRISIS
Since July 1994 two diseases of suspected viral etiology (YHD and SEMBV?) have had disastrous effects on shrimp farming which has upset the industry (Shankar and Mohan, 1994; Mohan and Shankar, 1995). YHD first occurred in several farms located on either side of Kandaleru Creek, in Gudur, Andhra Pradesh, along the east coast of India. All farms in this region were receiving and discharging water into Kandaleru Creek; none had reservoirs or sedimentation tanks. The disease affected only tiger shrimp (Penaeus monodon) (40-70 days old) in grow-out ponds. White shrimp (P. vannamei) stocked separately or together with tiger shrimp were not affected. Affected shrimp did not feed and had empty guts. At first, a large number of moribund shrimp were found near the pond margin and surface. The hepatopancreas of affected shrimp was reddish yellow or pale yellow in color and overall, the cephalothorax was yellow. Mass mortalities occurred within two to three days of the appearance of one or all of these clinical signs. To save the crop, many farmers resorted to emergency harvest.
In clinical signs, nature of mortality, species and size affected and, importantly, yellow coloration of the cephalothorax, the disease was very similar to yellowhead disease (YHD) caused by yellowhead baculovirus (YHBV). Confirmatory diagnostic reports are still not available.
The second disease, now recognized as white spot disease, affected the majority of farms in Andhra Pradesh and Tamil Nadu between November 1994 and January 1995. According to latest information, it is still spreading along the east coast to many parts of Orissa and West Bengal.
White spot disease affected all size groups of both tiger and white shrimp. Affected shrimp did not feed and had empty guts. Mortalities were low during the initial two to three days. A large number of circular white patches or spots were seen, first in the under surface of the cephalothorax and later in the carapace over the abdominal region. Mass moralities occurred within seven to 10 days of the first clinical signs.
In clinical signs, nature of mortality, and species and size affected, the disease is similar to IHHN caused by IHHNV. However, recently published work suggests that white spot disease is caused by systemic ectodermal and mesodermal baculovirus (SEMBV), a virus which has been responsible for the collapse of the industry in many parts of East and Southeast Asia (Nash, 1995).
It is estimated that these two diseases have caused a loss of nearly Rs 600 crores (US$ 17.6 million) to the industry. The Marine Products Export Development Authority (MPEDA), concerned research organizations and experts from the Asia-Pacific Region have all recommended “crop holiday”, waste removal from ponds, pond drying and disinfection programs to prevent recurrence of the disease.
INSTITUTIONS AND THEIR ACTIVITIES
The shrimp farming industry has grown very fast and in a haphazard manner. This rapid growth is one of the reasons for the lack of guidelines, feasibility studies, research input etc. to the industry. Below is a brief account of the various institutions involved in the industry and their activities.
Marine Products Export Development Authority (MPEDA)
MPEDA has been instrumental in promoting shrimp culture in India, setting up model state-of-the-art hatcheries and demonstration farms in many parts of India, and has successfully demonstrated the techno-economic viability of commercial shrimp farming. In addition, MPEDA organizes annual INDAQUA shows, workshops, training programs, expert consultations etc., involving farmers, industry and experts from India and abroad. As a part of the promotional program, MPEDA is also extending subsidy facilities to shrimp farming and participating in the equity of public limited companies.
MPEDA is actively associated with the ministry in farming policy guidelines and regulations relating to aquaculture. It can take the role of a nodal agency to implement policy regulations in different shrimp farming states.
Brackishwater Fish Farmer's Development Agency (BFDA)
Many of the maritime states engaged in shrimp culture have established BFDAs at the district level. Normally officers from the respective state fisheries departments are assigned to look after the activities of these agencies. These agencies are involved in identifying and earmarking government land under their jurisdiction suitable for shrimp culture and are responsible for leasing out this land to unemployed youth, people from the poor sections of society, individual entrepreneurs and companies. Organization of a large number of promotional programs, workshops, training programs etc. is also undertaken. In many states, BFDAs have successfully established model hatcheries and farms to demonstrate their techno-economic viability. Subsidy for shrimp farming originating from the individual state governments is routed to the farmers through BFDAs.
Fisheries Colleges and Research Centers
Teaching and research institutions coming under the university of Agricultural Sciences of Karnataka, Tamil Nadu, Kerala, Andhra Pradesh, Maharastra, Orissa and Gujarat are very closely associated with the activities of the rapidly developing shrimp industry of India. Fisheries colleges have been very successful in providing much needed technical manpower to the industry. These institutes and colleges are currently engaged in research in areas like shrimp nutrition, water quality, disease etc. Extension and training programs, and workshops are also routinely undertaken.
Central Fisheries Research Institutes
Several central research institutes i.e., Central Institute of Brackishwater Aquaculture (CIBA), Central Marine Fisheries Research Institute (CMFRI) and Central Institute of Fisheries Education (CIFE), are involved in research and extension activities and are closely associated with the shrimp industry. They also conduct workshops, training programs etc. for the benefit of farmers, technical personnel and the industry.
Non-Governmental Organizations
Several NGOs have been recently established. The Aquaculture Foundation of India (AFI), Karnataka Shrimp Farmer's Forum and the Karnataka Aquaculture Society are some of the leading organizations which are actively involved in promoting interaction between farmers, evolving joint agreements on water and waste management, and conducting training programs and workshops.
Big Industrial Houses
Many of the big industrial houses have established their own research and development (R&D) facilities. Some offer diagnostic services, organize workshops and training programs, publish extension literature etc.
Banks and Financial Institutions
Banks and financial institutions are heavily involved in extending loans for setting-up hatcheries, farms, feed mills, infrastructure, R&D laboratories etc.
Insurance Sector
Several insurance companies are involved in insuring against crop losses due to natural calamities and diseases.
International Organizations
International organizations like INFOFISH and the Asian Shrimp Culture Council (ASCC) disseminate a lot of useful information on feed, water quality, disease management etc. through newsletters. In addition, these organizations also conduct training programs and workshops involving experts from India and abroad for the benefit of the industry.
FUNDING SUPPORT
Until recently, funding support to shrimp disease research was very limited. The recent emergence of two deadly viral diseases and the trail of destruction that they have left behind have highlighted the need for systematic and coordinated research on shrimp diseases and their management. National and international funding agencies have now recognized the need to fund research so as to develop sustainable shrimp farming in India. Several research projects are in the pipeline and many more are likely to be funded in the near future. Funding support and coordination of research effort are needed within the country. The following are some of the national and international agencies which have funded or are likely to fund shrimp disease research in India:
Indian Council of Agricultural Sciences (ICAR)
Department of Biotechnology (DBT), New Delhi
Department of Science and Technology (DST), New Delhi
Department of Ocean Development (DOD), New Delhi
National Bank of Agriculture and Rural Development (NABARD)
Marine Products Export Development Agency (MPEDA)
Various state fisheries departments
Corporate houses
International Foundation for Science, Sweden
World Bank
Australian Centre for International Agricultural Research (ACIAR)
ACHIEVEMENTS
Indian shrimp farming is still in its infancy. The research effort that has gone into shrimp disease studies has been very limited and hence very limited progress has been made towards health management. The majority of the health management techniques and chemotherapeutic practices that are being followed are largely adopted from Southeast Asian countries. The marketing strategy adopted by the international feed suppliers has helped in the acceptance and implementation of several health management strategies. Some of the noteworthy developments that have taken place in the last three to five years in the Indian shrimp industry are discussed below.
Recurrent problems associated with luminescent vibriosis, external foulers, larval mycosis and MBV are being effectively managed in many hatcheries. The current practice of taking good quality sea water from bore holes sunk in the sea bed near the coast has kept many problems at bay. The use of pressurized sand filters, UV irradiation systems, better disinfection programs, and the effective use of antibacterials and other chemotherapeutants have enabled the hatcheries to function successfully in recent years. Chemotherapy for secondary and systemic vibriosis and external foulers in grow-out farms has been successfully adopted and standardized.
Having realized the importance of health management for successful aquafarming, the Government of Karnataka has established a Disease Diagnosis Centre at the College of Fisheries, Mangalore. This center has a mandate to offer disease diagnostic and health management services to the farmers of the state. Several maritime states are considering establishing such centers.
Several research projects on shrimp diseases have been initiated. Some of the priority areas that have been identified are development of immunodiagnostics for screening and rapid diagnosis, development of vaccines and immunopotentiators, shrimp virology and evaluation of routine health monitoring programs. Over the last two years, a large number of training programs and workshops involving experts from India and abroad have been organized. These training programs and the current crisis the industry is facing has certainly impressed upon farmers the need for effective health management strategies and proper regulations for sustainable growth of the industry.
Many public limited companies have successfully established R&D centers. These centers will play a vital role in implementing rational health management practices over large areas through satellite and franchise farming.
In view of the current crisis, the Government of India has decided to issue aquaculture guidelines to all the concerned states to ensure the safety and sustainability of all aquafarming operations. Earmarking specific areas, statutory “crop holiday” or crop rotation, restricting maximum stocking density to < 30 m2 and complete drying of the pond bottom for two to three months are some of the areas in which the Government has decided to issue guidelines.
CONSTRAINTS IN HEALTH MANAGEMENT
Management Constraints
Short gestation periods and high returns on investment have overshadowed many scientific and ecological considerations during the development of the shrimp industry. Adopting effective health management has therefore been very difficult.
Dependence on a common water source is the root cause of many problems Most farms do not have reservoir and sedimentation tank facilities. Lack of reservoir tanks makes it impossible to undertake prophylactic measures, while lack of settlement tanks for sedimentation and disinfection of waste water before discharge adds to the problem of health management. The majority of the farms are owned by small farmers (< 5–10 ha) and it will be difficult or them to make provisions for reservoir and sedimentation tanks.
Lack of a sufficient number of disease diagnostic centers.
Lack of a sufficient number of trained personnel for disease diagnosis.
Failure to implement routine health monitoring programs. From the point of view of chemotherapy, the normal practice of diagnosing the cause of a disease during a mortality serves little purpose.
The nature of the farms and the dependence on common water source make it very difficult to follow health management strategies at the individual farm level.
Lack of coordinated joint agreements between farms on waste disposal, effluent discharge and water intake.
Lack of awareness among farmers on the need for proper disposal of dead shrimp and waste water during and after a disease outbreak.
Constraints in Regulation
The nature and extent of the shrimp farming industry in India make it very difficult to follow standard and scientific health management strategies. Lack of adequate regulations and absence of nodal agencies to implement such regulations are serious constraints to enforcing strict health management over a large area. At the national level, there is no comprehensive aquaculture policy and there is no nodal agency to enforce regulations. Some of the important issues which need immediate attention are:
The process of disease notification is absent in the country and hence it is difficult to restrict in-country movement of infected seed and broodstock.
Quarantine programs for new introductions and imports are not effectively implemented.
Disease certification programs are not practiced.
Rapid disease screening systems are not available.
Enforcing 100% “crop holiday”, if and when required, is very difficult.
No effective regulations exist to check the misuse of antibacterials and other therapeutic chemicals.
Entry of pseudoconsultants and quacks has led to large-scale availability of bad quality chemicals and their misuse.
Lack of effective regulation and its implementation to halt the ecological degradation associated with unplanned mushrooming of farms around available water sources makes the problem of health management worse.
RECOMMENDATIONS
The Indian shrimp industry is still at a very early stage of development. The industry has enormous potential to generate much needed foreign exchange and significant rural employment. In the interest of the nation, it is essential that it develop in a planned and regulated manner on a sound ecological and scientific basis. This can be ensured only if proper future directives are developed and effectively implemented. The future directives should be in the areas of policy and regulations, management, and research and development.
Regulations
Practical and rational regulations should be developed and implemented to guide the development of the industry. Some important areas which need to be considered are:
Development of a comprehensive national policy on aquaculture.
Restriction of uncontrolled shipment and importation of broodstock and larvae.
Implementation of organized quarantine, eradication and health certification procedures.
Regulation of man-made canals and creeks bringing brackishwater deep into agricultural land.
Conversion of agricultural land to shrimp ponds.
Regulations to check the misuse of chemicals
Mandatory waste removal, drying and disinfection programs between crops at farms.
Enforcement of complete “crop holiday”, when required
Restriction of the maximum stocking density to < 30 m2
Management
Adopting some of the following management measures would go a long way in aiding the development of sustainable shrimp farming in India:
Routine health monitoring should be mandatory for all farms. Early detection of disease would permit rapid treatment, adjustment of management or emergency harvest.
Disease notification should be mandatory, so that restrictions can be enforced on movement of live seed and broodstock within the country.
Routine prophylactic husbandry practices should be made compulsory to obtain licenses, bank financing, insurance coverage, subsidy etc.
Each farm should allocate areas for reservoir and settlement tanks.
Waste management should be strictly enforced (sedimentation tank).
Organized disinfection programs should be implemented.
Community agreements in water management (water intake and waste water discharge) should be developed.
Closed/semiclosed systems of culture should be considered.
Mangrove destruction should be prevented.
Research and Development
Research and developmental work in the following areas would help evolve standard scientific health management tools:
Exploring the use of specific pathogen-free broodstock and healthy post-larvae.
Exploring the development and use of virus-resistant species.
Developing immunodiagnostic kits for rapid disease diagnosis, and screening of broodstock and post-larvae.
Determining the carrying capacity of brackishwater sources before developing farms and earmarking areas for shrimp farming.
Establishing disease diagnostic centers in shrimp farming belts.
Creating a national center of excellence in shrimp disease research.
Developing immunoprophylactics, including vaccines, anti-stress factors, immunostimulators etc.
Initiating work on kinetics of antibacterials in shrimp tissue, tissue residues, bacterial drug resistance etc.
Developing bioremediation technology for shrimp farming.
ACKNOWLEDGMENTS
The sponsorship received from FAO and the FHS for participating in the expert consultation is gratefully acknowledged. I thank the University of Agricultural Sciences for permitting my participation in this workshop.
REFERENCES
Felix, S., and M. Devaraj, 1993. Incidence of destructive MBV and IHHNV in a commercial shrimp hatchery. Sea Food Export J. 25:
Felix, S., I. Rachel, and V. Sunderraj, 1994. Wide prevalence of ciliate infestation in shrimp aquaculture systems of Tamil Nadu. Sea Food Export J. 25:
Karunasagar, I., R. Pai, G. R. Malathi, and I. Karunasagar, 1994. Mass mortality of Penaeus monodon larvae due to antibiotic resistant Vibrio harvey infection. Aquaculture, 128: 203–209.
Mohan, C.V., and K.M. Shankar, 1995. Mass mortality of shrimps along the east coast of India - viral pathogen suspected. Fishing Chimes, (in press).
Nash, G., 1995. SEMBV - an emerging viral threat to cultured shrimp in Asia. Asian Shrimp News, 20:
Ramasamy, P., G.P. Brennan and R. Jayakumar, 1995. A record and prevalence of monodon baculovirus from postlarval Penaeus monodon in Madras, India. Aquaculture, 130: 129–135.
Shankar, K.M., and C.V. Mohan, 1994. Kandeleru fed brackishwater farms in Gudur, AP - viral pathogen suspected causing massive tiger shrimp mortality. Fishing Chimes, September, 1994.