SUMMARY
1. INTRODUCTION
2. FISHERIES RESOURCES AND PRODUCTION
3. PERSPECTIVE PLAN
4. POTENTIAL FOR DEVELOPMENT AND RESEARCH TO BE UNDERTAKEN
5. FISH AND SHRIMP HEALTH
6. INLAND CAPTURE FISHERIES
7. MARINE FISHERIES
8. INFORMATION NEEDS
9. CONCLUSIONS
REFERENCES
by
M.A. Mazid
Director, Fisheries Research Institute, Mymensingh, Bangladesh
and
M.V. Gupta
Senior Aquaculture Specialist, International Center for Living Aquatic Resources
Management, Makati, Metro Manila, Philippines
In the agrobased economy of Bangladesh, the fisheries sector makes a significant contribution to nutrition, employment and foreign exchange earning. The vast water resources, covering some 4.3 m ha of inland waters and 480 km coastline, a subtropical climate and suitable soil and water conditions offer a very high potential for fisheries and aquaculture development. In spite of this, fish production was very low and quite static till 1985. The few development programmes, implemented at that time did not produce the desired results due to lack of research support. As a result, production targets as set for the Second and Third Five-Year Plans could not be achieved. On the other hand, establishment of the FRI in 1984 and subsequent generation of improved aquaculture and management practices have made a positive contribution to almost achieving the production target of 1.2 m tons in 1994-95, the final year of the Fourth Five Year Plan.
The review of the country's perspective plan which is now under preparation, identifies the poor socioeconomic conditions of the fishing and farming communities and the lack of integrated resource management research as lapses. Taking into consideration the aquaculture/fisheries potential and the constraints for development, priority research areas have been identified in freshwater, brackishwater and marine aquaculture, and in the management aspects of inland openwater and, marine fisheries. Aquaculture research has boosted this sector and shown an average annual growth of about 17 per cent in the last ten years, now contributing 25 per cent of the total fish production. Considering the enormous potential, research fields identified in freshwater aquaculture include:
- Integrated farming systems;
- Development of GIS and ecoregion specific culture practices;
- Fish feed development;
- Nutritional studies of commercially important fish;
- Development of breeding and culture practices for indigenous and endangered species;
- Pen and cage culture;
- Hatchery and culture system for Golda (giant freshwater prawn);
- Genetic improvement of cultured species; and
- Aquaculture development in FCDI areas and floodplains.
The suggested areas for brackishwater aquaculture research are:
- Hatchery technology for Golda and Bagda (P. monodon) shrimp;
- Improved shrimp production systems;
- Polyculture of shrimp and fish;
- Culture of non-traditional species like mud crab and environmental; and
- Socioeconomic aspects of shrimp culture.
In mariculture, research on culture and breeding of mullets, sea bass, grouper, oysters, clams and cockles, green mussel, pearl culture, seaweed culture, etc. is needed to be undertaken. This needs information to be collected on the extent and nature of:
- Inter-tidal waters;
- Climatic, hydrological and oceanographic conditions;
- Water quality;
- Existing stocks and distribution pattern of selected culturable species;
- Pollution etc.
Greater emphasis on fish and shrimp disease research is of obvious importance because of increased risk consequential to intensive aquaculture.
Inland openwater fisheries generating from the vast river systems and floodplains contribute about 51 per cent of the total production, that are facing a difficult situation due to over-exploitation and habitat degradation. It is necessary to undertake research on
- Fish stock assessment;- Population dynamics of major river systems and floodplains;
- Biodiversity;
- Stocking strategies for openwater bodies;
- Community participation and management strategies for the important riverine fishery like hilsa, pangasius and shrimp etc. in order to formulate appropriate management policy for conservation and sustainable production.
Marine fisheries production has significantly increased and more or less stabilized to a level at around 24 per cent of the total production. Management of the multispecies and multigear artisanal fisheries is rather complicated and information on the resources needed for the development of management measures necessary to obtain maximum sustainable yields are absent. The immediate research needs for marine fisheries development are:
- Stock assessment of pelagic and demersal resources;- Evolving appropriate catch monitoring systems;
- Development of a model for multigear/multispecies fisheries and to forecast the fish resources in time and space;
- Diversification of fishing methods for untapped and underexploited species;
- Identification of overexploited species and their management for conservation;
- Oceanography;
- Utilization of bycatch and low-value fish;
- Quality control; and
- Socio-economic conditions of fishing communities.
A strong database, effective inter-agency coordination and dissemination of information through electronic media are very much needed.
The three major intertwined challenges facing the world today are alleviation of poverty, meeting current and future food needs, and managing natural resources to assure sustainability. Poverty, combined with population pressures, land constraints and lack of appropriate production technologies for intensification, are a major source of environmental degradation in low-income developing countries (Pinstrup-Anderson and Pandya-Lorch, 1994). Aquatic resources have been identified as being important for food security and economic development in many developing countries. Internationally, fisheries and aquaculture products-are highly traded goods and the trade grew from 32 per cent in 1980 to 38 per cent of world production in 1990. By comparison, only 4 per cent of rice and 22 per cent of wheat are traded (FAO, 1993).
In the agrobased economy of Bangladesh, fish and fisheries play an important role, contributing 73 per cent of total animal protein intake, providing fulltime employment to 1.4 million people and part time work to 11 million, and contributing some 10 per cent to the total export earnings. An estimated 73 per cent of rural households are involved in subsistence fishing. During the last two decades, emphasis has been on developing the crop sector, with the result that cereal production has increased from 10.26 million tonnes in 1972-'73 to 19.52 million tonnes in 1992-'93 and per capita grain production has increased from 137.6 to 167.8 kg. NARS research efforts have played a crucial role in the successful increase in production (BARC, 1995). While the country is reaching self-sufficiency in cereal production, it has lagged behind in the fisheries and livestock sectors. It is only in recent years, when fish production has not been able to keep pace with increasing population and fishing pressures, that the awakening has come. It has been realized that fish stocks are not inexhaustible and that, to improve the situation and keep the fish stocks at sustainable levels, management has to be undertaken on a scientific basis. As production from natural resources declines, the world has been expecting aquaculture production to help bridge the gap between supply and demand. In these circumstances, the fisheries sector has become a major target in the country's development plans, and is being geared to meet the demand of increasing population through optimum utilization and development of aquatic resources on a sustainable basis.
Bangladesh has been bestowed with vast water resources in the form of rivers, estuaries, floodplains, ox-bow lakes, reservoirs, inundated paddy fields and ponds, covering a total area of some 4.3 million ha. It also has a coastline of 480 km. In spite of these resources, fish production in the past has been low, being 0.774-0.856 million tonnes per annum in the period 1984-85 to '89-90, with an annual growth of only 1.47-2.64 per cent. In recent years, however, there has been a substantial estimated increase in production, from 0.856 million tonnes in '89-90 to 1.08 million tonnes in 1993-'94, at an annual growth rate of 4.67-7.25 per cent (DOF, 1994). This has been due to the implementation of various research and development programmes. Nevertheless, production is far from satisfactory. A good part of the inland and coastal waters are either unused or underutilized. The dominant role of the fisheries and livestock subsectors in the agricultural scenario may be seen from the table below.
Table 1: Growth rate (%) in the agriculture sector (1990-1995)
|
|
1990-91 |
1991-92 |
1992-93 |
1993-94 |
1994-95 | |
|
Agriculture |
1.6 |
2.2 |
1.8 |
1.8 |
0.2 | |
|
Subsectors |
|
|
|
|
| |
|
|
a) Crops |
1.2 |
1.7 |
0.8 |
0.5 |
- 2.0 |
|
|
b) Forestry |
2.1 |
2.4 |
3.0 |
3.0 |
4.5 |
|
|
c) Livestock |
2.2 |
3.6 |
6.2 |
6.2 |
9.0 |
|
|
d) Fisheries |
5.8 |
6.5 |
6.6 |
8.7 |
8.5 |
Source. Director General, Department of Agricultural Extension, as published in the Bangladesh Observer on 16.10.95.
A review of previous plans indicate that fish production target, which was set at 1.0 million tonnes during the First Five-Year Plan (1973-'78), could not be achieved even at the end of the Third Five-Year Plan (1985-'90). The target was then set at 1.2 million tonnes by the end of Fourth Five-Year Plan (1994-'95), in order to increase per capita fish consumption from 20.5 to 25.0g/day. Against this target, a production of an estimated 1.17 million tonnes was achieved during 1994-'95.
If we look at why the targets set during the first three five-year plans could not be reached, it becomes evident that no major investment or effort was made to develop appropriate technologies and management practices for the development of aquaculture and fisheries. Only in the latter part of the Third Five-Year Plan and during the Fourth Five- Year Plan has the Government made investments in research, and these have started yielding results. It is a well-known fact that the national and international research initiated in the 1960s to increase yields of wheat and rice resulted in the Green Revolution that removed the threat of mass starvation that faced parts of Asia. Investment in research and technological improvements is imperative as they are the only options to assure sufficient production to meet future demands, and alleviate poverty, without irreversible degradation of the natural resource base.
The Bangladesh Government in its Perspective Plan (1995), has set fish production targets of 1.502, 1.824 and 2.180 million tonnes to be achieved by the years 1999-2000, 2004-2005 and 2009-2010, when the country's population is expected to be 136.3, 146.4 and 153.9 million, respectively, to provide per capita fish consumption of 28.38, 31.32 and 33.46 g/day. If these targets are to be achieved, the resource base for fish production must be kept in a healthy functioning state by protecting the regenerative potential of natural stocks, maintaining high quality, high diversity options for the genetic resource base for culture, and protecting the integrity of ecosystem functions in production systems.
However, the combined effect of crop intensification, flood protection measures and siltation are not only contributing to degradation but also to progressive physical alteration and shrinkage of natural water bodies. This is very unfortunate, because fisheries is more profitable, is a major source of animal protein for the rural poor, provides livelihood for a large population group and helps purification and improvement of the environment. Therefore, steps need to be taken to stop/control activities which result in loss of waterbodies. What is a waterbody today should not be allowed to be converted into a cropfield tomorrow. Rather, silted up or degraded natural waterbodies, must be rehabilitated and reconverted as aquaculture facilities.
The Perspective Plan has identified a number of areas where long- and short-term research needs to be undertaken to support development efforts. The identified long-term research areas were:
- Productivity management and maintenance of soil and water quality in ponds;- Population dynamics and stock assessment of commercially important riverine fish;
- Stock improvement of commercially important fish;
- Man-made changes in inland openwaters and their effects on fish reproduction biology, fish genetic resources and biodiversity;
- Coastal ecology, biodiversity and monitoring of manmade changes in the coastal environment;
- Mariculture of fin fish, oysters, seaweeds, crabs, molluscs, etc.;
- Productivity and stock assessments and migratory behaviour of the important marine fish; and
- Pearl culture development in the coastal and freshwater areas.
One area of research that does not seem to have been covered much in the proposed perspective plan for the development of culture and capture fisheries is the people involved, i.e., the fish farmers and the fishers.
The failure of technologies and management practices are often due to their mismatch with the social and economic conditions of the target beneficiaries of research. Very little attention was paid in the past to studying and improving the socioeconomic conditions of the farming/fishing communities and they were often identified as the causative factor for over exploitation and depletion of stocks. It is poverty that forces people to use natural resources in an unsustainable way, for their survival. Hence, it is important that adequate attention is paid in the future to studies on socioeconomic conditions of farming/fishing communities and to identify causative factors that are deterring their economic upliftment.
Another strategic area of research in the aquaculture sector is integrated resource management. As farmers are resource-poor, aquaculture should not be looked at in isolation, but as an integral part of their farming systems. With farming systems changing over time, integrated resource management research should be an integral part of the long-term research plans.
Taking into consideration the aquaculture/fisheries potential, the constraints for development and a detailed review of the proposed Perspective Plan, the areas where research needs to be undertaken, to improve productivity in closed waters and develop conservation and management strategies for openwaters, have been identified and are detailed in the following sections.
4.1 Aquaculture
4.2 Brackishwater aquaculture
4.3 Mariculture
4.1.1 Freshwater aquaculture
4.1.2 Development of GIS and ecoregion-specific aquaculture practices
4.1.3 Fish feed and nutrition
4.1.4 Breeding and culture techniques for indigenous, endangered species
4.1.5 Improved nursery management practices
4.1.6 Pen and cage culture
4.1.7 Development of hatchery and culture techniques for giant freshwater Golda shrimp (Macrobrachium rosenbergii)
4.1.8 Genetic improvement of cultured species
4.1.9 Ecological characterization of waterbodies
Throughout the world, aquaculture is being looked upon as a panacea for meeting the increasing demand for fish as catches from openwaters decline due to over-exploitation and degradation of fish habitats. Bangladesh is no different. Advantageously, it has 146,890 ha of ponds, 5,488 ha of oxbow lakes and 140,000 ha of brackishwater areas, where aquaculture can be undertaken. There are also large number of beels (natural depressions) where there had once been abundant fish. These beels, however, have silted up and, being used for growing paddy, are now fishless due to water shortfall and the use of pesticides in shallow water. Upgrading and maintaining the resource base properly will enable aquaculture both in beels and baors. In addition, there are some 8 million ha of paddyfields, where aquaculture can be integrated with rice farming.
These water resources offer excellent opportunities for culture of various species: carps, Tilapia, Catfish, various species of prawn and shrimp, etc. Though aquaculture is still in its infancy, it has shown an average annual growth of 16.8 per cent in the last ten years and contributed 36.7 per cent to the inland fish production and 25.30 per cent to the total fish production during 1993-'94. Production obtained from these aquaculture resources is still below optimum levels, being on an average 1700 kg/ha in the case of carp culture in freshwater ponds (1992-'93) and 250 kg/ha in the case of shrimp in brackishwater ghers (enclosures). To optimise production on a sustainable basis, research should be strengthened to develop improved aquaculture techniques/management practices and address the constraints facing the sector.
The Fisheries Research Institute (FRI) has, in the meantime, developed a number of improved aquaculture and management technologies which include:
- Culture and breeding of short-cycled fish like Tilapia and Sharpunti (silver barb).
- Breeding and culture of endangered species like Pangas, Pabda, Gulsha (Catfish), Mahseer etc.
- Polyculture of carps.
- Integrated poultry/duck-fish farming.
- Integrated rice-fish farming.
- Development and culture of hybrid Magur (Catfish).
- Development of cost-effective fish-feed.
- Nursery development.
- Breeding and culture of Golda shrimp.
- Hilsa fishery management.
4.1.1.1 DEVELOPMENT OF INTEGRATED FARMING SYSTEMS
Research undertaken in Bangladesh and elsewhere has shown that fish production of over 10 t/ha could be obtained through intensive feeding and fertilization of ponds. However, under the existing socioeconomic conditions in rural Bangladesh, intensive aquaculture is neither feasible nor environmentally compatible. Also, inputs needed for intensive culture systems, such as high-protein supplementary feeds, are not only expensive and beyond the means of rural farmers but are also in short supply. Research undertaken in recent years by the FRI has shown the feasibility of increasing fish productions to over 6 t/ha through polyculture of various species of carps, using agricultural wastes and by-products as feeds and fertilizers.
A key to sustainable aquaculture expansion is its potential to raise total farm productivity and profitability, particularly among resource-poor farm households. This will require rational management of natural resources, care for the environment, conservation of biodiversity, and equitable distribution of benefits among producers and consumers (ICLARM, 1993). Hence, it is necessary to develop fish production systems that easily integrate with the farming systems of different ecosystems and ecoregions. Integrated agriculture-aquaculture, which is an environmentally sound farming system, holds high potential for over 8 million ha of rice farms in the country. Research undertaken in recent years has shown the feasibility of integrating fish culture with rice farming and studies need to be undertaken to develop integrated farming practices for different rice ecosystems, such as medium lowlands, lowlands and deeply flooded lands. Besides, the technology developed for poultry/duck-cum-fish culture needs a coordinated effort (FRI, BLRI) for large scale multilocation research trials.
Though the country is small in terms of area, there is wide diversity in soil, water and climatic conditions and agriculture scientists have identified 30 major agroecological regions. Unlike in agriculture, where soils and soil fertility have been mapped upto thana/union levels, information with regard to aquaculture resource characteristics is not available. Hence it is necessary to develop Geographical Information System (GIS) for aquaculture and develop ecoregion-specific aquaculture technologies/management practices.
To increase fish production beyond the natural productivity of cultured waters, supplementary feeding is a must. A balanced feed, in terms of protein, fat, carbohydrates, vitamins and minerals, with optimum energy levels is essential for maturation and reproduction, besides growth.
The nutritional requirements vary from species to species and at different stages of their life history. In many countries, formulated feeds are developed for specific species, depending on their nutritional requirements. Fish-feeding practices in Bangladesh are quite arbitrary and do not conform with the actual or specific nutritional requirements of the species being cultured. This obviously hampers production. Therefore, the knowledge of the exact requirements of fish, both in terms of major and trace elements, is much needed in order, to be able to develop quality feeds not only to maximize production but also to ensure the quality of aquaculture production.
At present, farmers in Bangladesh use rice bran and oil cakes (mustard, peanut, soybean, etc.) as supplementary feed in carp culture, while fish meal is used additionally in prawn and catfish culture. Fish meal is in short supply and not easily available to farmers. Hence, a substitute for fish meal needs to be identified. Surveys undertaken by the FRI have revealed a number of indigenous ingredients of plant and animal origin which could be used in formulating fish feeds (Bhuiyan et al, 1989).
The production of agricultural by-products and wastes, which have been traditionally used as the major sources of fish feed, is being reduced day by day due to country's chronic problems of flood and drought. On the other hand, the demand for supplemental fish feed is increasing with the expansion of aquaculture. Therefore, to meet the increasing needs of the developing aquaculture industry, research needs to be undertaken to develop of nutritionally balanced feeds for Carp, Catfish, prawn and shrimp nursery, growout and broodstock ponds using conventional and unconventional feed resources. As feed plays a role in maturity of fish, feeds for fish species which do not easily mature in captivity should be developed. It is essential to establish a fish feed mill which will allow production of commercial as well as experimental fish diets.
In order to make aquaculture more successful and profitable, it is of utmost importance also to undertake research to determine the optimum level of requirements of different individual nutrients for fish of high commercial value. This will need the establishment of a modern fish nutrition laboratory with sophisticated equipment for biochemical analysis of fish and feed ingredients.
Habitat destruction, as a result of siltation, pollution and changes in hydrology of the rivers due to human interventions, has resulted in certain species of fish becoming extinct or endangered, threatening the aquatic biodiversity. It is necessary to develop breeding and culture techniques for these endangered species, in order to save them from extinction. The FRI has already done some work with regard to the breeding of some of the endangered species such as Pabda (Ompok pabda), Gulsha (Mystus cavasius), Mohashoal (Tor putitora) and Pangasius spp. This research needs to be continued to develop techniques for other threatened species and to develop culture practices. Seed production and culture technologies also need to be developed for such non-conventional fish as Snakehead (shoal and taki). Climbing Perch (koi) Catfish (Boal, Air, Rita) and Eel (Baim).
Nursery operation is a very promising occupation, particularly for resource-poor farmers on account of its high assurance of quick return. Rapid expansion of aquaculture and the stocking of floodplains and other openwaters have resulted in increased demand for quality fingerlings of specific species and sizes, at specific times. This necessitates nursery management practices that could ensure large-size fingerlings for stocking in openwaters at the beginning of the season. Floodplain stocking programmes experience high mortalities of fingerlings due to transport over long distances and poor handling. Hence, it is necessary to identify suitable areas near floodplains, including beels and seasonal waterbodies, for nurseries and develop appropriate management practices.
There are thousands of hectares of irrigation and roadside canals and burrow pits in flood control and drainage development areas and deeply flooded lowlands which are, at present, lying fallow. They could be utilized for fish culture by constructing pens. Cage culture of fish could also be taken up in these water resources by landless farmers, especially women.
While cage culture is a form of intensive aquaculture in developed and some of the developing countries, it has to be an extensive culture under Bangladesh conditions, as supplementary feeds needed for cage culture are in short supply and expensive. Hence, low-input, low-cost cage culture techniques, using species which could grow well on agriculture by-products and wastes, need to be developed. While pen culture technology has been developed for irrigation canals, techniques need to be developed for other ecosystems.
Catches of Golda shrimp (M. rosenbergii), which used to be a lucrative fishery in some of the rivers in the past, have declined. The species commands a high price in the domestic market and has high export potential. About one fifth of the total export of shrimp is contributed by M. rosenbergii. A large number of farmers are evincing interest in its culture. One of the constraints for its culture is the shortage of seed. While a few hatcheries have been established in the private sector in the last couple of years, the technology has not been perfected and the hatcheries are still facing problems in respect of breeding and larval rearing. Hence there is urgent need to develop techniques for the establishment of small-scale viable hatcheries, as has been done in Thailand.
The vast inland freshwater area offers tremendous potential for commercial culture of Golda shrimp, which has a high export potential. At present, culture of this shrimp, either in monoculture or in polyculture with Carps in ponds and ghers, is expanding fast, especially in the Bagerhat, Khulna and Satkhira Districts. As it has considerable scope to spread all over the country and as the production obtained at present is very low using the traditional systems, culture techniques need to be improved through appropriate research.
Significant gains attained in agriculture have been attributed to genetic research and breeding programmes. Though fish-farming has been in vogue for hundreds of years, the aquaculture sector has not been touched by advances in applied breeding technology. A few studies undertaken in recent years for genetic improvement of Salmon and Tilapia have indicated that the potential for achieving rapid genetic gains is generally very high. The freshwater aquaculture industry is at present dependent on hatchery bred stocks. Due to the unconscious negative selection from finite populations of brood in hatcheries, inbreeding is taking place. This is resulting in reduced growth and deformities, drastically affecting aquaculture production. It is an established fact that in genetically closed systems, potential selective pressures exerted on finite and, often, small culture populations by various farm management practices result in indirect selection of important life history traits, inbreeding and genetic drift (Doyle, 1983). As these hatchery-produced seed are being stocked in floodplains and rivers, wild populations of Carp could also be affected if care is not taken. Hence, it is necessary to take up selective breeding programmes to develop better strains of cultured carps. To meet the tremendous need for carp fingerlings, and knowing that private hatcheries are their major source, proper broodstock care and management, selective breeding and improved nursery techniques need to be perfected and disseminated to the hatchery owners to ensure quality fingerling production.
Aquatic ecosystems, their flora and fauna, and the dynamics of bio-physicochemical phenomena are highly diverse in Bangladesh. This is mainly because of its subtropical climate, its natural features, climatic conditions, its flood-and cyclone-prone nature, and its mainly alluvial soils which have their* origin in deltaic plainland crisscrossed with over 250 rivers.
The large area of floodplain, once estimated to be about 6.3 m ha, has reportedly been reduced by about 0.81 m ha by flood protection measures (MPO, 1987). Inside the floodplains, there used to be a large number of beels (natural depressions) which were perennial in nature. Heavy siltation, due to erosion and the construction of a large number of FCD and FCDI structures, has progressively increased sedimentation in waterbodies, turbidity, temperature, salinity and fluctuations in oxygen and other limnological parameters. Approximately 2 billion tonnes of silt are carried to the rivers and sea from upstream.
All these result in loss and degradation of habitat, alteration of ecology, impediment to population recruitment, loss of primary productivity and biodiversity etc. However, the dynamics of changes in soil and water quality, flood and drought, habitat topography, temperature, salinity and primary productivity are not well known. It is necessary to know more about them to make long-term predictions on the type of changes going to take place over time and space. This information is needed for long-term planning and development of ecoregion specific aquaculture and fisheries management practices for sustainable development. Therefore, research on dynamics of changes and the characterization of all waterbodies (both lotic and lentic) need to be carried out for the zonalization of the huge waterbodies of the country.
4.2.1 Development of hatchery technologies
4.2.2 Improved shrimp production systems
4.2.3 Polyculture of shrimp and finfish
4.2.4 Culture techniques for non-traditional species
4.2.5 Environmental and socioeconomic impacts of shrimp culture
Brackishwater aquaculture, particularly of shrimp, is fast expanding in Bangladesh due to the high demand for its products in the world market. The most commercially important brackishwater shrimp are Bagda (Penaeus monodon) and the white shrimp (P. indicus). Shrimp culture area has expanded from 20,000 ha in 1980 to over 140,000 ha in 1994 and production has increased from 2,220 t in 1982-83 to 57,000 t in 1994-95. While gross production has increased, production per unit area is very low, being 100-150 kg/ha in traditional extensive systems and about 250-350 kg/ha in improved extensive systems. Semi-intensive culture, through higher stocking, supplementary feeding, aeration and water exchange has indicated productions of 2,500 kg/ha.
Indiscriminate horizontal expansion of the industry has resulted in a shortage of seed, disease leading to mass mortality of culture stocks, and environmental and social problems. Unless these constraints are addressed through solutions to problems, the sector cannot progress. The areas where research needs to be undertaken, for development of environmentally compatible management practices, are discussed below.
Seed is the main input for any aquaculture operation. At present, a major portion of the seed of Bagda shrimp (P. monodon) is collected from natural resources. But the availability of seed from Nature is erratic, unreliable and is on the decline due to various reasons. Mortality of seed collected from Nature is high, due to the crude methods used in collection and transportation. It is estimated that over 50 per cent of the seed collected dies before reaching the shrimp farms.
It has been estimated that over three billion P. monodon seed are annually collected from natural sources. Along with the desired P. monodon post-larvae, fry of a number of other finfish and shellfish are caught, but are destroyed, as they are discarded on the shore. Studies undertaken by the FRI indicate that for every single P. monodon post-larva collected, 40 other shrimp and 10 finfish seed are destroyed (Mazid, 1994).
With the expansion of shrimp culture area and also intensification, the demand for shrimp seed has increased, but the collection from Nature is not able to meet the demand. Only in recent years have a few hatcheries been established in Bangladesh, but their production is very low. These hatcheries are also facing several problems. With the result, to meet the demand, seed is being imported from neighbouring countries, and these are bringing in additional problems, such as disease.
If the growing shrimp culture industry is to be sustained, it is imperative that research is undertaken to develop simple, low-cost hatcheries. The FRI in recent years has made some strides in the development of a prototype backyard hatchery for Golda (M. rosenbergii). These research efforts need to be strengthened. At the same time, surveys need to be taken up for charting shrimp breeding grounds and assessing fry resources over time and space.
Another constraint faced by the hatcheries in many countries is non-availability of brood of Bagda, P. monodon. Though this is not yet a problem in Bangladesh, due to the very low requirement of broodstock for the limited number of hatcheries, it will become a major constraint in the near future if the expected increase in the number of hatcheries materialises. Hence, it is imperative that studies be undertaken on the maturation of shrimp in captivity through eye ablation and other techniques. Also, research should be undertaken to develop appropriate gear for secured and safe collection of Bagda brood by the artisanal fishermen.
As has been mentioned earlier, shrimp production from extensive systems has been very low, while semi-intensive systems have led to disease resulting in crop losses. The information available in Bangladesh and elsewhere indicates that semi-intensive and intensive systems are fraught with uncertainties and might not be suitable under Bangladesh conditions. Therefore, the objective in Bangladesh should be to increase sustainable production with minimum cost. In view of this, it is necessary to develop improved extensive systems by proper pond preparation, soil and water quality management, low stocking densities and feeding, but at the same time ensuring higher productions.
There are excellent brackishwater finfish species, such as Mullets and Catfish, that could be cultured either in mono- or polyculture along with shrimp. This would involve less risk, be less capital intensive and would also demand less shrimp seed. While these fish are cultured in other countries of the region and have high demand, there is no experience with them in Bangladesh. This necessitates taking up research to develop breeding and culture techniques for these finfish. Polyculture of fish and shrimp as well as the culture of fish and shrimp in rotation reportedly reduce the risk of shrimp disease. Such cultural practices needs to be examined through research.
Besides shrimp and finfish, there are other species, such as mud crab (Scylla serrata), which have high export potential and could be cultured in mangrove swamps, mud flats, creeks etc. High export potential has resulted in their being caught in large numbers, resulting in declining populations in the wild. The seed of mud crab is available in abundance in the Khulna region. However, techniques for its culture are not known and need to be developed.
Haphazard expansion of shrimp culture has led to environmental degradation in terms of destruction of mangroves, pollution of tidal rivers and inshore waters, salinisation of soils, loss of grazing grounds for livestock, loss of freshwater sources, etc. Shrimp culture expansion has also led to social conflicts over land tenure and use rights, leading to marginalisation of small rice farmers who have been forced to lease their lands to large shrimp farmers. Unless these problems are addressed and redressed at this stage, it might lead to irreparable damage to the environment and the socio-cultural ethos of the shrimp culture areas.
To save the environment from degradation, it is necessary to undertake surveys to identify and demarcate areas for shrimp culture. Unplanned expansion of shrimp culture and unregulated discharge of shrimp farm enffluents not only threaten the shrimp farms, by way of their intake of polluted water, but also other aquatic flora and fauna present in the ecosystem. Therefore, the negative impact of shrimp farming on the aquatic environment needs to be studied in order to develop mitigating measures against these impacts.
Great strides have been made in mariculture/coastal aquaculture of commercially important species, such as Grouper, Snapper and Sea Bass, in neighbouring countries. This has proved to be an attractive venture for small-scale farmers/fishers. But very little is known of the potential for culture of marine species (other than shrimp) in Bangladesh. Mullet (Mugil spp.). Sea Bass (Lates calcarifer) and Grouper (Epinephelus spp.) are of commercial importance in the domestic market as well as for export. Hence, studies should be undertaken to assess the availability of seed of these species in the wild and seed production and culture techniques for these species should be developed.
Culture of edible oysters, clams and cockles is practised extensively throughout the world and there has been increasing interest in such culture in the tropics to meet the demands of domestic consumption and export. Preliminary surveys have identified a number of species of edible oysters (Crassostrea spp., Saccostrea spp.), windowpane oysters (Placuna placenta), pearl oysters (Pinctada sp.), clams and cockles (Anadra spp., Meritrix spp.) and green mussel (Perna viridis), which are suitable for commercial culture (Pagcatipunan, 1982). At present, the meat of shellfish is consumed only by low-income groups and is also used as feed in shrimp culture. The shells are crushed and used as lime. Feasibility studies need to be undertaken for their commercial culture and marketing of shellfish. Efforts also need to be made to develop techniques for the culture of pearls.
Seaweed is cultured in large quantities in many coastal areas of Asia. Nearly 90 per cent of the world production is from the Asia-Pacific region. Demand for seaweed is growing, as it is used as human food, as a component of animal feed and as a raw material in industry. Several species of seaweed have been identified in Bangladesh (Islam, 1876). Studies need to be undertaken to assess the feasibility of culturing them on a commercial scale.
Accurate information on coastal areas of Bangladesh is needed in order to take decisions on the use and management of its coastal resources, as very little information is available at present. It is imperative that information be collected on:
- The extent and nature of inter-tidal waters.
- Climatic/hydrological/oceanographic conditions.
- Water quality.
- Existing stocks and distribution of selected culture species.
- Access and pollution.
Intensification of aquaculture, which necessitates greater use of fertilizers and supplementary feeds, increases the risk of disease outbreak in cultured waters, leading to mass mortalities and economic losses. One such example in the case of freshwater finfish is the recent large-scale outbreak of the epizootic ulcerative syndrome (EUS). Also, losses of fish seed have been reported in recent years from hatcheries and nurseries.
Disease to shrimp has become a major problem in recent years and has led to great losses to shrimp producers. Very little is understood of the aetiology of shrimp disease, with the result that any suggestion made to shrimp growers is only on the basis of empirical knowledge. Hence, it is necessary to understand, through research, the environmental parameters that trigger disease, identify the causative pathogens (bacteria, virus, fungus) and formulate measures to control disease.
Well-equipped fish health laboratories and skilled manpower are needed for research. At the national workshop held in 1994 in Cox's Bazar and Khulna, a strong recommendation was made to establish two modem fish health research laboratories at the Marine and Brackishwater Stations of the FRI at Cox's Bazar and Khulna in order to render services to the shrimp farmers of those two important shrimp culture areas. Substantial investment is needed for the establishment of these two laboratories.
6.1 Fish stock assessment and stocking strategies for floodplains
6.2 Community participation in inland openwater fisheries management
6.3 Hilsa fishery management
6.4 Population dynamics and stock assessment of carps and prawns in the major river systems
6.5 Aquatic biodiversity
The major river systems of Bangladesh have a total length of 22,000 km and provide a base for artisanal and subsistence fisheries, which contribute over 51 per cent to the total fish production. These fisheries provide employment to a large section of the population who are involved in fishing and ancillary industries. Production from inland capture fisheries has been on the decline in recent years, due to over-exploitation and habitat degradation. While it is difficult, if not impossible, to regenerate and improve openwater fisheries, even small improvements in average yield would significantly increase national fish production, because of the large extent of openwater resources. Hence, it is necessary to undertake appropriate conservation and management measures to improve and sustain production.
Being situated in the delta of three major rivers, Bangladesh has one of the largest floodplains in the world. Some 2.8 million ha retain water for periods ranging from four to seven months and contribute substantially to fish production. These floodlands are repositories for mineral and organic matter washed down by seasonal flooding, resulting in high primary productivity. They play a major role in providing breeding, nursing and grazing grounds for commercially important species. They also play a role in repopulating the openwater fishery system, including rivers and estuaries. In recent years, implementation of various irrigation and flood control projects has resulted in reduction of habitat, inhibition of breeding and feeding migrations of fish, reduction in productivity and decline in fish production. Composition of species has changed in favour of sedentary species which are of less economic value (Tsai and Ali, 1988). All these changes have resulted in a decline in annual fish production from the floodplains of 2.4-2.9 per cent. This has also resulted in declining recruitment to the riverine fisheries, which is evident from the declining trend in riverine catches.
In recent years, the Government has taken up programmes to stock the floodplains, with a view to increase fish production. For these programmes to be successful and sustainable, it is necessary to understand the dynamics of the floodplain ecosystem.
Openwater stocking of fish is an important tool for stock replenishment. However, stocking of floodplains in Bangladesh is being undertaken on an ad hoc basis, without a full understanding of the productivity and carrying capacities of these water resources, the population dynamics of the existing fish stocks and the socioeconomic conditions of the fishing communities dependent on these wetlands. For the regeneration of the fish populations in the floodplains and the sustainable management of the resources, it is necessary to undertake studies on the biological characteristics of these floodplains and develop stocking strategies.
The economic conditions of fishing communities are deteriorating due to the decline in openwater fish catches as a result of the degradation of fishery resources and fish habitats as well as due to lack of access to common property waterbodies. Government policies in the past were not conducive to benefitting the fishers, whose livelihoods are linked with fishing in these waterbodies, nor to the ecological sustainability of these water resources. In recent years, the Government has introduced a New Fisheries Management Policy in a few public waterbodies. Under this policy, short-term leasing has been replaced with licensing of genuine fishermen. Even with these waterbodies, there have been problems in benefitting the genuine fishers, who have to depend on moneylenders for equipment (boats and nets) and operating capital, and the subsistence fishers, who were excluded from the programme. Also, in the absence of any assessment of the exploitable biomass, adjustment of fishing pressure and long-term planning could not be undertaken. Hence, it is necessary to undertake studies to develop a system by which the fishing community can participate in the management of the openwaters.
Hilsa is the largest single species fishery in Bangladesh, contributing nearly 25 per cent of the total fish production. There is also thriving fishery for the young of Hilsa, generally known as Jatka. It has been estimated that some 4,000 tonnes of Jatka are annually caught from a section of the Meghna River. Some estimates suggest that a 10-20 per cent conservation of Jatka would be equivalent to an additional 40,000-100,000 tonnes of Hilsa.
Studies undertaken by the FRI in recent years have resulted in the identification of some of the spawning and nursery grounds of Hilsa, an anadromus fish. In view of the importance of this fishery, it is imperative that it is protected and managed at optimum levels. For this it would be necessary to study the population dynamics of the Hilsa, make an assessment of the stocks, identify different sub-populations, identify and protect spawning and nursery grounds and undertake steps to conserve its young, the Jatka.
Populations of carps and prawns are on the decline. There is considerable overfishing of broodstock, mainly major carps, during the spawning and dry seasons when the floodplains dry up and fish congregate in the beels. This results in a negative impact on recruitment, leading to a decline in overall fish production in the floodplains and rivers. Hence, the population dynamics of these commercially important species need to be studied, to enable formulation of appropriate management measures.
Biodiversity, the genetic library maintained by natural ecosystems (Ehrlich and Wilson, 1991), is the basic biotic resource that sustains all human life-support systems (Kim, 1993). Fish are the fifth largest agricultural resource and are the primary source of protein to over one billion people. Yet, aquatic biodiversity remains a neglected issue. Recent estimates suggest that, worldwide, 20 per cent of all freshwater species are either extinct, endangered or vulnerable (Maclean and Jones, 1995). The major causative factors for decline in aquatic biodiversity are: degradation and loss of habitat, over exploitation, spread of exotics, pollution, and climate change. Conservation of biodiversity rests on resource management, that is, sustainable management of stocks and preservation of the habitat.
The biodiversity of Bangladesh's water resources, especially in the floodplains, is one of the richest in the world. However, it is under threat due to overexploitation, loss of habitat, water pollution, etc. Surveys need to be undertaken to assess the fauna in these water resources, identify the species extinct or endangered, identify causative factors, and suggest remedial measures for conservation of threatened species and biodiversity.
7.1 Productivity and stock assessment of demersal and pelagic fish resources
7.2 Utilization of by-catch
7.3 Studies on the socioeconomic conditions of fishing communities
7.4 Quality control of fish and fish products
Marine fisheries has shown a steady growth over the years and landings have increased from 10.6 per cent of total fish production in 1970 to 24 per cent in 1993-94 and has more or less stabilized. Of this, the artisanal fishery, comprising of some 17,000 boats of different sizes, of which 6,000 are mechanized, contributes 95 per cent of the catch. The artisanal fishery, especially the set bagnets, exploit the juveniles and post-juveniles of different species. In recent years, there has been a substantial increase in fishing effort, leading to overexploitation of coastal stocks, with a resultant decrease in catch per unit effort.
The offshore industrial trawl fishery is, relatively, a new development and at present 53 trawlers are in operation, of which 40 are engaged in shrimp trawling. Overall shrimp catches have dropped in recent years. The problem is further compounded by the increasing exploitation of shrimp seed from inshore and estuarine waters, to meet the demand of expanding shrimp culture activities.
While the inshore fish and shrimp stocks are under heavy fishing pressure, exploitation of pelagic resources, like tuna, mackerel, sardines and anchovies, and demersal stocks beyond 40 m depth, is constrained by a lack of knowledge of the resource as well as of the means to exploit it. Surveys undertaken of demersal and pelagic stocks in the past have come up with different estimates (Khan, 1994; Mazid, 1994). Very little effort has been made in the past to assess the size of stocks of different species of finfish and shellfish and implement management measures to obtain maximum sustainable yields. Information on oceanographic parameters, i.e. temperature, salinity, turbidity, water current, mixing and upwelling, organic productivity and its potential of fish yields as well as their relationship with the standing stock and resulting landing is also absent. In the absence of a database on standing stocks, catch statistics, gear selectivity, fish behaviour, etc. of both inshore and offshore stocks, and oceanographic parameters, it would not be possible to come up with any management solutions for conservation of depleting stocks and increased exploitation of underexploited stocks. In view of this, research in the following areas is suggested.
It is high time that research is initiated for the assessment of stocks of commercially important species of fish, especially Hilsa which contributes about 46 per cent to the total marine landings (and 13 per cent of inland catch), and shrimp exploited by the artisanal fishery, with a view to understanding the fishing effort at which maximum sustainable yields could be obtained and to develop management measures for rational exploitation. Along with this, an assessment of the stocks in pelagic fisheries (Tuna, Mckerel, Sardines, Anchovies etc.) that are at present unexploited or underexploited needs to be undertaken and fishing grounds charted. There is at present intense fishing upto 40 m depth by the artisanal fishery and 100 m depth by the industrial fishery whereas both pelagic and demersal resources beyond that remain unidentified and untapped. Research studies need to be undertaken to identify and determine the stock size in the deep sea and should include:
- Development of a suitable model for multigear/multispecies fisheries and to forecast the fish resources in time/space;- Development of diversified fishing methods to tap underutilized species, particularly pelagic ones;
- Development of gear on the basis of fish behavioral studies;
- Identification of overexploited species and their management for conservation, particularly of Hlsa and shrimp;
- Development of different models of community-level participation in conservation management;
- Understanding the marine ecology of the area, and assessment of the primary and secondary productivity of the EEZ of Bangladesh;
- Relating marine fish stock assessment with marine productivity and marine fish landings;
- Development of various methodology to monitor the catches and fishing efforts of Bangladesh's marine fisheries; and
- Development of suitable catch monitoring systems to assess the status and trends of resources in catch.
With the introduction of trawling for shrimp, a considerable amount of by-catch of low-economic value is being discarded at sea by trawlers. The amount of by-catch discarded at sea has been estimated at around 50,000 tonnes a year. In a country where there is shortage of fish, the nation cannot afford to discard this low-cost animal protein which can benefit low-income population and which can also be used as fish meal. In view of this, it is necessary to develop techniques to process by-catch and small pelagic fish as surimi and other value-added products.
The 93 processing plants in the country are at present working at nearly 13 per cent of their capacity. If appropriate methods are developed for the processing of by-catch and small pelagics, these processing plants would be able to utilize their unutilized capacity without additional investment. The important areas of research are as follows:
- Development of techniques for the processing of by-catch and small pelagic fish to make improved quality surimi and other value-added products; and- Developments of techniques to screen protein concentrates, both qualitatively and quantitatively, from by-catch and small pelagic fish.
It is estimated that over 500,000 full-time fishers at present depend on marine fisheries for their livelihoods. The number of marine fishers has increased by 50 per cent from the period 1979-80 to 1988-89, putting pressure on fisheries and resulting in overexploitation of stocks and decline of household incomes. Any effort made to enforce laws or control fishing effort with a view to sustaining the fishery will be futile, unless the fisher communities cooperate and become partners in government efforts aimed at rational exploitation of stocks. To achieve their cooperation and participation, it is important to understand and improve the socioeconomic conditions of these fisher communities and create awareness among them of the need for conservation and management of resources. Hence, demographic surveys of fishing villages need to be undertaken to assess their economic condition and social problems, and come up with measures for improving their living standards, which, in turn, could lead to better implementation of measures aimed at the sustainable exploitation of fisheries resources.
Fish and shrimp being important tradeable commodities in the international market, their quality has to conform to international standards. This is particularly important in case of shrimp, which in the case of Bangladesh is 100 per cent exported. Buyers from the USA, Japan and EEC are greatly concerned with poor hygiene and sanitary conditions in processing plants and suggest quality control through Hazard Analysis Critical Control Point (HACCP).
As domestic demand for fish exceeds supply, traders are not concerned with improving the quality of transport, processing and marketing. Post-harvest care in handling, transporting, washing, icing, packing etc. have a direct bearing on the quality of the product. Good sanitation at ice plants and freezing and processing plants are extremely important for quality control. Research support is needed for ensuring the quality of fish and fish products (dried and salted fish) for both the domestic and export markets. The immediate areas of research should be to:
- Survey quality control systems in different processing plants and the transport system and the loss of quality at these stages;- Deterioration of organoleptic quality of Hilsa and shrimp under varying conditions;
- Biochemical changes occurring in fish, particularly Hilsa and shrimp, during different stages of handling, transport, processing and preservation, affecting their quality;
- The bacteriology of Hilsa and shrimp preservation; and
- Development of standard methods of quality control, quality protection and quality assurance.
Development of technologies or management practices by itself is not enough to reach the goal of increasing production. Available information indicates that there is a large gap in productivity between what has been achieved in research organizations and the farmers' field or by the fishers. This is because research results do not easily percolate to the beneficiaries or to the implementers of management measures. This is because of weakness in the system of technology transfer and information dissemination.
A large number of government and non-government organizations are involved in the dissemination of modem techniques/management tools to fish farmers/fishers. Regular coordination meetings between these organizations on the one hand and between these organizations and the farmers/fishers on the other hand could help in speedier dissemination of research results and, at the same time, provide feedback to the research. Since the majority of rural farmers/fishers are illiterate, the electronic media could be an economical way of reaching information to this section of the population. Also, good coordination between researchers and planners/administrators is needed for policy support to the planning and implementation of development programmes and also for the conservation of resources.
While the resources for fish production in Bangladesh are vast, there are many constraints, biological, social and economical, which need research to be undertaken in order to harness the full potential. Studies undertaken in different countries, to assess the impact of agriculture research, have concluded that research did increase production from a given resource and has been very cost-effective. Fisheries research in Bangladesh is in its early stages; investments made in it in the past were negligible. To conserve and manage fishery resources for the benefit of the present and future generations, the resources need to be managed and exploited on a sustainable basis. This needs continuous information-support through research. The research areas identified in this paper are comprehensive enough to assist the authorities in formulating appropriate management plans for conservation of the resources and optimization of production, in consonance with ecology, economics and equity. To achieve this goal, Government has to commit long-term funding for research backed by qualified manpower. The organizational structure of FRI has to be strengthened by upgrading the position of the Director to Director-General like other similar organizations. There is also a great need to improve research facilities and establish Fisheries Research Laboratories at the 19 greater district head quarters.
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