Fisheries & Environment

Dr. M.A. Mazid, Director
FRI, Mymensingh

1. Introduction

Fisheries resources of Bangladesh are highly diversified in resources, type and nature. The inland fisheries resources are constituted by rivers, estuaries, canals, floodplains, oxbow lakes, reservoirs and inundated paddy fields and ponds covering an area of 4.3 m ha. The culture fisheries include ponds - 0.15 m ha, oxbow lakes - 5488 ha and coastal shrimp farms 0.11 m ha. The country has a coast line of 480 km along the Bay of Bengal with an area of 64,000 sq km, which supports artisanal and commercial fisheries as well as provides opportunities for aquaculture development. In addition to these, the country has 200 miles of EEZ Zones in Bay of Bengal.

The current level of fish and shellfish production in Bangladesh has been estimated to be about 1.04 m tons. According to the latest available statistics, 71% of this comes from inland waters and 29% from marine. Of the inland production, 69% is from capture fisheries and 31% from culture. The inland openwater fisheries production declined markedly from 0.47 m tons in 1983–84 to 0.44 tons in 1985–86. However, aquaculture production has been steadily rising showing a growth of 31% over the last 5 years although its contribution to total production is only 22%. But ample scope remains to increase aquaculture production through semi-intensive or intensive culture technologies.

Table 1. Area under different fisheries production systems with their contribution to total fish production.

The inland aquaculture is mainly practised in the central districts of Dhaka, Mymensingh, Kishorgonj, east and north eastern districts of Comilla, Chandpur, Noakhali, Feni, Sylhet, Moulavi Bazar, Sunamgonj, southern districts of Jessore, Jenaidah and north and north western district of Pabna, Sirajgonj, Natore, Rajshahi, Noagoan, Kurigram etc.

Shrimp culture in the coastal belt has been expanded greatly during the last decade because of increasing demand and price of shrimp in the international market. Recent survey indicates that land for shrimp culture has increased from 52,000 ha in 1982–83 to 0.11 m ha in 1992–93. 75% of the area is located in the southern districts of Khulna, Bagherhat and Satkhira whereas the rest is in the south eastern district of Cox's Bazar.

2. Species cultured and culture systems

Freshwater aquaculture of Indian and Chinese carp popularly known as Composite Fish Culture is undertaken commercially in freshwater ponds since late 1980s. Culture of different carp with varying species combinations is undertaken with supplemental feeding and fertilization. This system of culture yields a production of 5–6 ton/ha.

Monoculture of tilapia, puntius and catfish (both African and indigenous) are practised under improved management method. The rate of production obtained for tilapia was 6–7 ton/ha, puntius, 3 ton/ha and African catfish over 60 ton/ha.

Freshwater prawn Macrobrachium rosenbergii is cultured both as monoculture and polyculture with carp in pond with a very low rate of production (350 kg/ha). Freshwater prawn and tiger prawn are primarily cultured in brackishwater ponds following traditional and improved extensive cultural practices. The average production rate under this system is extremely low ranging from 180–200 kg/ha. Both giant and tiger shrimp are traditionally cultured in coastal enclosures locally called ‘Gher culture’. ‘Gher’ plots are of few hundred ha in size where juveniles are trapped through allowing tidal water into the enclosure and holding it for 4–5 months for prawn to grow.

Recently, farmers have initiated semi-intensive shrimp culture using pelleted feeds and obtained production as high as 5 t/ha which is comparable to any other country in the world. Presently 0.11 m ha area is under shrimp farming. However, according to a recent estimate, the area suitable for shrimp culture in the country is about 200,000 ha.

Culture of sea bass in the coastal area is now picking up. To promote aquaculture Government has already announced the technology based fish and shrimp farming as industry and made provision for industrial and bank loan on soft terms.

Marine Fisheries

Marine fish catch from both industrial and artisanal fisheries has been increasing rapidly in recent years, mainly because of the introduction of trawlers, mechanized fishing boats and efficient fishing equipment.

However, the marine fishery is predominantly artisanal in character with almost 14,000 crafts, of which about 80% being non-motorized. But industrial fishing is limited to some 50 shrimp trawlers. Except for the few trawlers owned by the Bangladesh Fisheries Development Corporation (BFDC), the great majority is privately owned, some being operated on a partnership basis. Thus, around 95% of the marine fish catches are taken by artisanal fishermen and the remaining 5% by the industrial trawlers. However, in terms of value, the industrial sector is of great importance because of landings of high-valued shrimp. But at the same time it is also responsible for destruction of about 30,000 tons of by-catches or trash fish per annum.

3. Government Priorities for Fourth Five Year Plan (1990–95)

The government has identified the objectives of the fisheries sector and has set the following priorities for Fourth Five Year Plan (1990–95)

• To increase fish production for domestic consumption.

• To improve the socio-economic conditions of fishermen and others engaged in fisheries and create additional employment opportunities for poverty alleviation.

• To enhance the fisheries resource base through extension of commercially important fisheries in unexplored and under exploited areas.

• To enhance fish production and management technology.

• To train required manpower at all levels for facilitating the transfer of technology.

• To increase foreign exchange earnings through export of fish and fisheries products.

• To improve general environment and public health.

4. Pollution of Fisheries Environment

4.1 Pollution of Fisheries Resources

Industrialisation, urbanisation, and use of chemicals are increasingly polluting the aquatic environment through indiscriminate dumping of all forms of wastes, both solid and liquid into rivers, causing damage to the propagation of fish.

The major industries causing chemical pollution to aquatic environment are paper and pulp mills, rayon mills, tanneries, fertilizer and pharmaceutical factories, jute, sugar and steel mills, rubber, chemical, and fish processing industries, oil refineries, machine tool and soap factories etc. Most of these industries do not have waste treatment plants and thus discharge untreated industrial wastes and effluent, domestic organic wastes (sewage) etc. directly or indirectly to the water bodies. Sylhet pulp and paper mills at Chatak, Karnaphuli paper mills at Chandragona, Fertilizer factory at Fenchugonj and Ghorashal, Hazaribag tanneries in Dhaka contributed to the depletion of fisheries resources of many rivers like Surma, Karnaphuli, Kushiara, Sitalakhya and Buriganga. Large scale mortality of fish at Sitalakhya river was due to raw ammonia released from urea fertilizer factory, Ghorasal. Fish mortalities in waterways near Mubarakgonj sugar mills in Jhenaidah and Setabgonj sugar mills in Dinajpur district have been reported due to the effluent discharge from these mills.

4.2. Human and Agrochemical Pollution of Fisheries Resources

Use of pesticides and fertilizers are increasing day by day in the country. Annually 4,000–5,000 tons of pesticides are used in Bangladesh. Recent survey revealed that fish mortality is mainly because of agriculturists using either higher dose of pesticides or forbidden pesticides. Aerial spray of chemicals used for mosquito control also kills fishe and other aquatic organisms.

Organochlorine pesticides are highly toxic to fish and other aquatic organisms. A few drops of endin normally kills all fish in a pond. In sub-lethal doses, they affect the reproductive physiology of the fish. Indiscriminate use of pesticides is one of the major causes of declining flood plain fisheries in the country.

The disposal of human wastes except in some parts of the cities is not hygienic. Human excreta collected/discharged into septic tanks ultimately find their way into the river or sea.

4.3. Pollution by oil

The main sources of oil pollution are refineries, garages, discharge from tankers, navigation, etc. It is observed that the major rivers and estuaries in the vicinity of Chittagong port receive waste oil from ships, tankers and refineries which ultimately pollute the water.

5. Turbidity and Salinity Effecting Fisheries Environment

High water turbidity as a result of carrying approximately 2 billion tons of silt every year from the upstream is a major constraint to water quality and productivity in the country. This affects the natural nursery ground of the fish.

High fluctuations in salinity is another important constraint to year round aquaculture practice.

6. Impact of aquaculture on the environment

6.1 Inland aquaculture

6.1.2. Physical factors

Because of extensive resource base, favorable climate, water and soil characteristics, aquaculture has an enormous potential for expansion. However, the rate of expansion is not very high and still over two-thirds of the country's 1.3 m ponds remained unutilized.

Oxygen depletion during prolonged rains and algal blooms during sunny days sometimes occur. Also manuring and fertilization of ponds and supplementary feeding of fish result in plankton bloom and increase bottom residues in the pond, ultimately resulting in poor water quality.

6.1.3. Chemical factors

Following chemicals are used in freshwater aquaculture but no serious deleterious effects have been reported to any other organisions.

6.1.4. Interaction between aquaculture and native species

Introduction of exotic species like silver carp and common carp compete for feed with indigenous Catla catla and Cirhina mrigala respectively. The exotic African catfish Clarius garipinus is a voracious eater. Natural food chain gets disturbed with the artificial stocking of floodplains with incompatible exotic species.

6.1.5. Social conflicts and aquaculture

The pond waters in rural areas are mostly used for household purposes. Application of cowdung, and other chemicals prevent the farmers from using the water for house hold and for drinking purposes. Conflict often arises over the use of water for crop production.

6.2. Coastal aquaculture

Coastal aquaculture is charactisized mainly by shrimp culture in Bangladesh. Large areas of mangrove forests have been cleared for the development of shrimp farms in the south and southeastern part of the country. More and more areas are being brought under shrimp culture. The conversion of land into pond damages the terrestrial plantation and grazing ground, which affects the surrounding ecosystem.

6.2.1. Shrimp farming and coastal ecology

Unplanned growth of shrimp culture has a serious effect on alteration of coastal ecology. Tidal land previously used for rice cultivation has been changed to shrimp farm by dyking the river bank. This results in inundation of rice field by saline water and obstruction of breeding and feeding movement of fish and shrimp. Large number of males and females including children are getting increasingly engaged in shrimp fry collection. While wild shrimp seed collection has other adverse effect, dragging of net by thousands of fry collectors everyday causes river erosion and increase siltation.

6.2.2. Shrimp farming and wild seed collection

Fry collection from the wild presently provides employment opportunity to many but this is not beneficial to the nation when compared to the loss it results in the form of ecological alteration, environmental degradation and change in natural balance in fish population.

In order to reduce the impact of shrimp fry collection, the Government is planning to expand its support to establish hatchery in the private sector. Establishment of shrimp estate and construction of required infrastructural facilities for the private entrepreneur etc. are included in the Govt. plan. The plan also includes proper land use pattern for shrimp farming.

6.2.3 Shrimp farming and removal of mangroves

The Sundarbans mangrove forest in Khulna, the southwestern part of the country, cover nearly 60,000 ha which is the largest single compact mangrove resource in the world. The south eastern part, the Chakaria Sundarban in Cox's Bazar, is also having mangrove forest which has virtually been cleared off for shrimp culture. However, the pond yield is very poor which indicates that the conditions are not optimal. The destruction of mangrove forests has also reduced protection of inland area against cyclones and tidal waves and increased salinity by tidal water. The conversion of mangrove forest to fish farms would appear to be uneconomical if the potential yields are compared with the combined yields of the forests and the traditional fisheries, which are now both lost.

6.2.4. Other conflicts

Recent upsurge in shrimp farming has created certain problems and conflict with other farming systems like rice cultivation, salt production etc.

Government is planning for zonation for shrimp culture and for proper land use pattern in coastal area for planned and compatible speedy development of shrimp farming.

FRI has initiated survey and monitoring the performance of the practices of the shrimp farming with a view to develop improved methods of production and is presently rendering technical services to increase the production.

7. General remarks

From the above account it is clear that fisheries resources are indeed under great strain. I have not dealt with massive flood control programmes and their effect on fisheries. I tried to indicate more of status of fisheries and environment. However, it is most essential that all concerned should realise that fisheries and aquaculture are seriously affected by disruption of environment because they are directly depended upon environmental quality of water & soil. Fish, fisheries and aquaculture should be used as bio indicator and even instruments of environmental conservation and fishermen as scientific supervisor and inspectors of permanent witnesses of the environmental studies and changes because their income and livelihood depend directly on it. No government machinery can cope up with the extensive monitoring of such diverse ecosystems and it is but natural to get the fishermen scientifically trained and involved directly in monitoring and managing the aquatic resources and the fisheries.

Environment and Fisheries Research

M.M. Abdul Matin
Joint Secretary
Ministry of Fisheries & Livestock

We can approach the concept of the environment from two angles. First, the more familiar understanding of environment is achieved on a micro-level. This aspect of the concept of environment involves our immediate surroundings. Everybody can see and act on the positive and/or negative changes of this small scale environment. The second understanding is a macro one, where environment has a global application. In this planetary understanding of environment, not only individuals but nations get directly involved. Both of these concepts/perceptions are interconnected and this is the main spirit of the future of the modern environmental approach. The individual environmental consciousness is as necessary and important as the planetary approach. In fact, if some industry, for example, releases toxic wastes into one river this will destroy directly the biocenosis of this river. But some pollutants have long term effects and can go to the ocean via streams. One typical example is illustrated by the very significant presence of lead in Antarctic and Arctic areas coming from the industrial wastes that are spewed out in the atmosphere. One other example is the effect of discharging TFC (Tri-Fluoro-Carbons) on the zone and of the UV penetration through the atmosphere. This increased exposure to UV may affect the basic genetics of life and modify all members of the Plant and Animal Kingdoms (marine and terrestrial). Everybody is of course aware of the greenhouse effect in relationship with the discharge of CO₂ which can induce dramatic consequences (increase of Ocean water levels which can entail disappearance of countries like Bangladesh and the Netherlands). Environmental action can not be truly effective in one country if there is no involvement of all other countries.

If environmental action is to be considered at all, it must be considered within the context of social issues or the social environment. A densely populated country, such as Bangladesh, may have difficulties allocating the countries resources to a population of 115 million people. With a population growth rate of approximately 2.7%, this has exceeded the economic growth rate in the past, and is therefore going to produce a difficult environment for the majority of the population who live below the poverty line.

In assessing the quality of the environment one needs to establish a baseline survey of the present situation and develop an awareness of the factors that have impact on this present situation. By defining these parameters one can begin to identify those areas that are most damaging to the environment as well as those that offer the greatest potential for improving the environment. From this an action plan can be developed to begin the process of developing a sustainable system of environmental improvement.

This action plan must be centered around the needs of the people and targeted toward effective development of awareness of their role in and impact on the environment. While the expanding and rapidly developing technologies of enhancing our environment are tools that we should use in this action plan we must not let ourselves be fooled into thinking that technology will solve our problems. In the final analysis the problems of the environment are the problems of people. People problems can not, at their root, be solved with revolutionary technology but instead must be solved with changing peoples ideas and attitudes. This is the hardest task faced by any programme that hopes to result in success. As such it is frequently the task least often undertaken due to the difficulty of achieving success.

As the people of Bangladesh are aware, our environment has changed dramatically over the past thirty years. Our population continues to increase at a rate that is placing us on the path to ruin. Given our current situation we are trying to divide a pie that is too small between a population that is on the verge of being too great. We must find ways to both increase the size of that pie and to slow the growth of the number of people that it must sustain. These solutions must be effective in terms of both costs and of acceptability to the people. They must be sustainable and supportable. While we may have passed the point or, given the new global thinking, the need to be a self-contained and self-sufficient nation, those resources we utilize from within our borders and those resources we acquire from our neighbors must not be utilized in such a way that our environment is rendered inhospitable to the people who inhabit that economic and political niche.

Environment from the Fisheries point of view

The Inland Fisheries and Marine Fisheries environments inspite of the water composition differences (regarding mainly mineral and nutrient concentrations) and whole species composition differences, have the same means of interaction with the surrounding environments via the interfaces of the atmosphere, soil basins and the inflowing and standing water. While the interface between the soil and the fresh water basins can result in heavy metals concentrating within the bottom muds and silt, the marine water tend to concentrate more pollutants than streams and rivers due to the eventual flow of contaminated freshwater into the oceans.

Inland water and marine environments can be polluted by direct dumping of wastes into the water bodies, by contaminated water entering through soil percolation/infiltration or by atmospheric pollutants settling into the water column. These atmospheric pollutants may be manmade pollutants or “natural pollutants” resulting from volcanic eruption (from inland or from the abyssal rifts explosions) or large scale forest fires. These pollutants from the atmosphere are introduced through concentration of the pollutants in rain droplets and can have very adverse impacts such as the well publicized effects of “acid rains”.

Pollutants, based on their toxicity and activity duration, can be classified as follows:

• Short term effect: Organic matter, acid, domestic wastes. These can induce a strong effect and mortality according to the concentration/quantity introduced but are generally quickly rendered harmless by natural factors such as volatilization, settling or by biodegradation.

• Medium term effect: Cationic detergents, some organochlorinate compounds. These can remain active during a period of 1 to 10 years because natural biodegradation is slow and not always effective and they are not volatile compounds.

• Long term effect: Polyaromatic hydrocarbons, anionic detergents, heavy metals, industrial wastes. These can remain for a very long time in the environment because there is no way (or only a very slow process) for achieving their degradation.

It is important to highlight that some pollutants, as for example detergents and some hydrocarbons, can be degraded quickly but the first degradation product can be more toxic than the original compound. Sometimes detergents are used to disperse oils to avoid big coastal pollution by hydrocarbons when a petroleum tanker loses its contents. This process sinks the hydrocarbons to the ocean bottom and the pollution apparently disappears but this only shifts the pollutant load to the bottom where time for natural biodegradation of petroleum is higher than in the surface waters due to the relationship between bacterial and their oxygen needs for achieving biodegradation.

It might also be important to make differences between chronic pollution and accidental pollution. While accidental pollution can induce important environmental changes and damages, which mobilize the international opinion, chronic pollution can have more important impacts on the destruction of the environment. Moreover chronic permanent pollution is generally not as visible as accidental pollution and thus may be overlooked by or have a smaller impact on the international community.

There is no single treatment for pollution. Each pollutant is unique. The environmental pollution can more surely be treated by raising the consciousness of everyone concerned about the environment and by developing a real commitment to a cleaner world. National and international policy approaches to the environment can only be applied and effective for the larger point sources of pollution such as factories, industrial and urban wastes.

Environment and Aquaculture:

The marine and freshwater aquacultures can introduce pollution into the surrounding environment. This is mainly evident with intensive, and at a lower level, semi-intensive aquaculture techniques. Extensive aquaculture generally uses a very small quantity of fertilizers/nutrients and other inputs such as artificial feeds.

The primary problem induced by intensive aquaculture is the production of high organic matter contents in soil and in water which can induce toxic levels of ammonium and ammonia in the water bodies receiving water from these aquaculture facilities. The use of pesticides and other organochlorinates should be totally avoided. As a matter of fact, these products are very toxic and remain in the environment for a long time. It is better to use natural products like tea seed cake or chemicals such as Rotenone which are very quickly (12 hours) rendered harmless.

The introduction of exotic species in aquaculture should be made with a lot of care because this can change and sometimes destroy the natural biocenosis.

The destruction of coastal estuarian areas, such as mangroves habitats, should be avoided if we do not want to destroy the natural reproduction process of numerous marine species. This has already occurred in Equador, and at a lower scale in Indonesia, where thousands of hectares of mangroves were destroyed to permit construction of ponds to be used for shrimp culture.

Conclusion

Fisheries is an important economic sector for a developing country like Bangladesh. It is imperative that the environment should be able to sustain the activity, and not be destroyed by it. This involves re-evaluating our relationship with our immediate surroundings. A cleaner environment can ensure a healthier existence for plant and animal life. Fisheries activities should not diminish the environment but, at a minimum, at least maintain the status quo. Intensive aquaculture practices in many countries, unfortunately, are destroying precious marine life. An organic approach to fisheries, where chemicals are avoided and natural nutrients are used for fish cultivation, is an ideal solution. Faced with increased needs, we may have to resort to use of some chemicals and face the prospect of some pollution increase but taking care that we do everything we can, to protect the environment.

Environment has too long been taken for granted. It is time we become aware of its depletion and desecration. In the developed countries of the world environment friendly programmes have been undertaken in almost all sectors of economic activities. Bangladesh has to replicate some of them in her fisheries sector. Otherwise, we may end up with double jeopardy - no environment and no fishes That would be situation we would not like to see ourselves in. We have the means to avoid the catastrophe, let us apply then with earnestness.

GOB Environmental Guidelines For Fisheries and Aquaculture

A.K.M. Abdus Sattar
Joint Chief, Planning Commission

1. Introduction :

Bangladesh has extensive water resources within her boundaries and territorial water as EEZ in the Bay of Bengal. The fisheries resources are broadly divided into inland and marine. The inland fisheries resources of the country are considered to be very rich both in terms of area and the potential for development. Inland fisheries resources consist of impounded waters, inundated crop fields and openwaters. There are 1.28 million ponds covering an area of about 0.15 million hactres. The area of the inundated low-lying crop fields varies considerably in time and space depending on the intensity of monsoon. However, the ecosystem provides feeding and breeding grounds for various species of freshwater fish and shrimp. The Oxbow Lakes (baors) covering an area of about 5.6 thousand ha. and Kaptai Lake of an area of about 56.00 thousand ha. are also important sources of fish production. The area of inland openwaters (such as rivers and their tributaries, beels haors and estuaries) is estimated to be 4.05 million ha of which about 25 percent are rivers. The country has a coastal belt of 480 km. and its EEZ in the Bay of Bengal.

2. Production and Export Performance

The fish production target during the terminal year of the Fourth Five Year Plan has been set at 12.0 lakh tons of which the inland production at 9.38 lakh tons and marine production at 2.62 lakh tons. The export target fixed during the terminal year of the plan period would generate a foreign exchange earning to the tune of Tk. 971.50 core by exporting about 45,000 tons of head on shrimp, 17,000 tons of fish and fish products and 2,000 tons of other aquatic organisms. As against the above target, fish production and export achievements during first and second years of the Fourth Plan are shown in the following tables.

Fish production target and achievement during the first and second years of Fourth Five Year Plan.

(In Lakh Metric ton)

Fish export target and achievement during the first and second years of Fourth Five Year Plan

(Qnty. in thousand MT value in core taka)

3. Implementation Problems/Constraints :

Inspite of the tremendous potential of fisheries development in the country, fish production could not keep pace with the demand. As a consequence, per capita availability of fish has declined over the years causing nutritional problems. There are various impediments to fisheries development. Some are internal to the sector and some are external. The internal factors are inadequate technical knowledge and technology know-how, lack of proper management policy, problems of property rights, competing water uses and related conflicts, lack of trained manpower and water pollution.

The external factors are related to construction of flood control, drainage and irrigation projects (FCDI), industrial pollution, urbanisation, use of agro-chemicals etc. They have adversely affected the fisheries resources.

4. FCDI Projects :

Without proper environmental evaluation particularly in respect of its adverse impact on fish production, many flood control and irrigation projects were implemented to increase crop production. These projects have badly affected ecology of fish habitat which had adverse impact on fish production.

5. Industrial Pollution :

Total number of industries generating wastewater from production operations has now risen to over 1,200 units. With a few exceptions, industries are not equipped with pollution control systems: Only one tannery is known to treat its wastewater effluent. Of the five urea plants operating in Bangladesh, only two are equipped with ammonia stripping units. None of the pulp and paper mills have means for wastewater treatment, except the Karnaphuly mill, which neutralizes its effluent. All the 300 industries under Dhaka Municipal Corporation, do not have facilities for treatment of the waste water.

Management of hazardous wastes from industrial activities in the country is by and large very poor with industries having virtually no accountability of the types and quantities of the wastes and their mode of disposal. Tanneries in Hazaribagh have been operating there over the last 30 years and producing about 40 tons of solid wastes daily with about 50 percent hazardous wastes having high chromium content, which ultimately drain to the river floodplain.

6. Agro-chemical Pollution :

Bangladesh is blessed with natural soil fertility for crop production. Labour intensive farming, supplemented with organic fertilizer and green manure comprise traditional farming practices. The use of inorganic fertilizer was initiated in 1950. In the mid 1960's, high yielding varieties (HYV) of rice were introduced, which greatly increased the use of chemical fertilizers and pesticides. Since 1973, the acreage covered by HYV rice production has increased over 200 percent. Urea, Triple Super Phosphate (TSP) and Muriate of Potash (MP) are the major chemical fertilizers used. The total amount of fertilizers used annually in Bangladesh is about 1.0 million tons, an increase of 20 per cent over the last four years, and 400 per cent since 1977.

Pesticide use was introduced to Bangladesh in 1957. The year 1981 was peak year for pesticide coverage, during which over two million acres (0.81 million ha) of paddy received some form of chemical protection. Yet there is still no effective control on the use and abuses of pesticides at the field level.

The impacts of the use of agricultural chemicals in the country are not well documented. While, nitrate contamination of groundwater is expected, it is also doubted that pesticide residues are common in surface water system especially in irrigation drains.

7. Urban Pollution:

Urban pollution represents the combined results of industrial, commercial and domestic activities. Urban pollution is present in all common forms, as wastewater and polluted surface waters, air emissions from vehicles and solid wastes. Visual observations in any of the major urban centres of Bangladesh bear out that significant problems exist for control of urban pollution.

8. Guidelines and Standards:

The regulatory mechanism is weak and existing legislation is inadequate to effectively monitor or prevent discharges. The proposed “Environmental Protection Act”, which will replace the “Environment Pollution Control Ordinance of 1977”, is currently under consideration by the government and if approved in its full form, it will significantly improve accountability for waste discharges.

9. Strengthening of DOF:

DOF is weak in term of manpower and physical facilities for monitor and manage aquatic environment. It needs to be immediately strengthed and equipped. Since, environment preservation is multi-disciplinary issue, various agencies need to be involved. Department of Environment and Ministry of Environment and Forests are focal agency and Ministry for effective control of the situation with the co-operation of all concerned.

General remarks

1. There is no specific qualitative and quantitative environmental standards and guidelines for various sectors in the country. Inadequate, incomplete and draft legal standards are available. They will take sometime to take proper shape. Two Technical Assistance Projects are under consideration for developing sector specific guidelines and standards. Ways and means for enforcing them need to be developed.

2. Establishment of pollution monitoring system and monitoring network is essential in order to obtain reliable information.

3. Qualified manpower is needed for Environmental Impact Assessment (EIA). A Technical Assistance Project is under implementation for training officers on the subject.

4. Implementation of formal and non-formal environmental education and promotion of linkages between concerned institutions are highly essential.

5. Introduction of industrial waste permit system and inspection procedures and their effective enforcement are needed.

6. Evolving an appropriate environment-friendly technology is imperative so as to ensure sustainable development.

7. Involvement of institutions, mass-media and NGO's is essential in dessemination of knowledge, and to undertake programmes for maintaining quality of soil and water for fish production.

8. Procurement of a laboratory ship for marine environment surveillance is essential.

9. Recommendations of FAP-17 on fisheries should be nationally accepted and to undertake measures for mitigation of adverse effects.
   A project for compensating fish production loss in 17 FCDI projects is under implementation in pilot basis.

10. In future water development project, fishery aspect should be kept in view and the assessment of effects on fisheries need to be made.

11. Preservation of mangrove forests is essential to provide nursery environment, food and shelter to shrimp and other estuarine living resources.

12. It should be mandatory for shrimp farmers to grow mangrove forest around the farm where such forest does not exist.

13. Establishment of hatcheries for production of juveniles for shrimp culture.

14. Overfishing should be controlled by imposing restrictions on gears and their mesh sizes and prescribing catch quota in different fishing grounds. Rules and regulations exist for imposing restrictions through Fish Preservation Act 1950. However, proper implementation of the provisions of the Act is required for which necessary facilities and manpower need to be made available.

15. Direct discharge of untreated toxic pollutants into rivers from industries located in different parts of the country should be banned and it should be made obligatory on the part of the industries to treat the toxic wastes before discharging into water bodies. Environment Pollution Control Act 1977 exists, but due to some inherent shortcomings in the text, the Act could not be enforced effectively. A new comprehensive law is pending in the Ministry of Environment and Forest.

16. Specific environmental standards are required to be made for various Industrial Sectors. At present there is no sector specific guidelines in the country. Arrangement should also be made for monitoring as per standards.

Conclusion

Formulation of a national policy on use, conservation and development of fishery resources is a prerequisite for all development. Such a policy has been drafted in the Ministry of Fisheries and Livestock in September, 1990. It is hoped that the draft policy is finalized at the earliest and steps would be taken for implementation. It is also contemplated to develop an industrial pollution control credit facilities to encourage industries to introduce environmental control measures.

WATER RESOURCE DEVELOPMENTS AND FISHERIES - THEIR INTERPLAY ON ENVIRONMENT

DR. V.R.P. SINHA
FAO/UNDP, Senior Specialist,
Fisheries Research Management and Development

1. INTRODUCTION

It is well known that Bangladesh has very high potential for fisheries development with many water bodies having high primary productivity. The whole country offers ideal ground for spawning and nursing of riverine, estuarine and marine migratory fishes. However, the country is at the same time perennially vulnerable to high floods, repeated cyclones and abrupt typhoons. To cope up with the natural flurry and calamity, certain measures are taken which sometimes are protective to human beings and for the community development. These interventions result in some cases in immediate perceptible adverse effects on the aquatic ecosystems and in other cases in long term permanent damage.

Mismanaged or under utilized primary productivity in the country leads to eutrophication of ponds and lakes resulting in water quality problem around. This ultimately gives rise to an array of undesirable symptomatic changes, including production of abnoxious algae and other aquatic plants, deterioration of water quality, taste and odour problems and fish kill, each of these significantly interferes with human use of water resources. Coupled with these, presence of pesticides and other pollutants in the water aggravates the situation.

Siltation is yet another serious problem. It is estimated that 2.4 billion tons of silt pass annually from Bangladesh through the river systems compared to 1 to 2 billion tons in South and North American rivers respectively. It is estimated that amount of silt passing over to the Bay of Bengal has increased a hundred times in the last century. This causes obstruction of the outlets of lagoons and estuaries and has adverse effect on the carrying capacity of the Bay.

If a river is channelled or dammed, its capacity for self purification gets reduced and the original fabric of aquatic ecosystem damaged, destroyed or modified. Similarly embankment of the coastal area to prevent incursion of sea water to inland results in salinization of inland area because it impairs the drainage of inland water and thus water logging occurs.

Similarly indiscriminate shrimp farming in coastal area is causing problem to the coastal habitat like lagoons, estuaries, mangrove and coastal wetland. Mangrove ecology is seriously disturbed which has long term effect on the population dynamics and stocks of brackishwater and marine fishes. Thus, it appears that many, if not all, the “assets” of fisheries of the country are gradually becoming “liabilities” either by natural causes on man made changes.

2. MAN MADE DEVELOPMENTS AND FISHERIES

2.1 WATER RESOURCE DEVELOPMENT CONFLICTING WITH FISHERIES

1. Dam Construction

   • Man made lakes replacing long stretch of flowing rivers cause abrupt change in the ecology.

   • Temporary diversion or disruption of long stretch of river causes change in ecological conditions.

   • Large scale earth moving, clearance of forest, importation of migrant labour and subsequent activities involving the establishment of new community disrupt partly or wholly the whole ecosystem.

2. Agricultural Development

   • Fertilizers and biocides drainage in the ecosystem normally harm the fish.

   • Drainage of large areas of natural fish producing wetlands, swamps, ponds, pools and puddles reduces and affects flood plain fisheries.

   • Diking of sea or river banks to prevent inundation changes the aquatic ecosystem.

3. Industrial Development

   • Iron, steel and other chemicals industries discharge both air-borne and water-borne harmful waste materials to the aquatic ecosystem.

   • Agricultural related industries producing pesticide, fertilizers, oil, animal feed, implements or involved in processing discharge harmful waste materials to the ecosystem.

   • Similarly river-transport industries involved in navigation improvement, discharge harmful waste material to the ecosystem.

   • Increased riverine vessel traffic, urban and municipal wastes are detrimental to the ecosystem.

4. Flood control

   • Results in reduction of fisheries because of reduction or elimination of seasonal inundation of alluvial lands particularly in the low-lying river mouth and coastal areas.

5. Navigation Improvement

   • Dredging and deposition of the dredged spoil, waste oil, sewage, and other materials from the transport vessels disrupt the aquatic ecosystem.

2.2 MAJOR IMPACTS OF WATER RESOURCE DEVELOPMENT PROJECTS ON FISHERIES

1. Upstream fish & fisheries (Behind the Dam)

   • Riverine Fisheries ecosystem changes to Lacustrine Fisheries ecosystem.

   • Flood Plain Fisheries get reduced.

   • Distribution, abundance and survival of the exclusively upstream fish species are affected.

   • Hill stream fishes are adversely affected by increase in turbidity and organic content of the water.

   • Oxygen limit in the water gets adversely affected.

2. Mainstream Fish

   • Preferred habitat gets reduced.

   • Fish food species such as riverine insects, molluscs and other invertebrates get affected.

   • Suitable spawning sites get reduced.

   • Shelter areas for fish get reduced.

   • Agricultural activities increase the nutrient load of the river.

   • Upland mainstream fish species particularly isolated head water species suffer most.

3. Tributary Fishes

   • Tributary species normally have wide environmental tolerance and thus they are not affected that much.

   • Upland tributary fish suffer most, because of further isolation-particularly in dry season.

2.3 WATERSHED MODIFICATIONS PARTICULARLY FOREST MANIPULATION AND LIKELY RESPONSE OF FISH TO THESE CHANGES

• Removal of trees results in the alteration of stream flow, increased upstream erosion, turbidity of water, siltation down stream and increased water temperature and its fluctuation, and also salinity.

• Increase in the velocity of streams results in a large number of fish eggs and benthic organisms getting dislodged.

• Increased frequency of substrate shift adversely affects the fish.

• High turbidity causes inflammation of the gill and kill young fish.

• Fish feeding visually are unable to stay in increasing concentration of silt load but fish species using sensors for locating food move in.

• Sand, silt and clay are poor substrate for fish food organisms.

• Fine deposits of silt in the spawning areas suffocate eggs, embryos, and young fish and their food.

• Suspended clay particles are known to reduce feeding rates of some planktivorous fish.

• Silt provides ideal substrate for bacterial growth and bacterial infections flare up in water with heavy silt.

• Elevated silt load chokes existing aquatic vegetation and thus affects the ecology and substratum for fish food organisms.

• Siltation reduce the lagoon fisheries.

• Increased water temperature and its fluctuation affects life history of the fish and has adverse affect on survival, growth and feeding.

• Rise in temperature increases the fish pathogens and also increases the rate of eutrophication.

• Increased salinity affects spawning & growth in the fishes.

2.4 WATER QUALITY AND STRUCTURE OF THE ENVIRONMENT

1. Topographic changes acting directly on the major aspects of biology of the fish

   • Reduction or change of habitat.

   • Barrier or deterrent to upstream and downstream migration.

   • Deposition of sediments in downstream areas and turbidity during construction.

   • Reduction or elimination of a salinity gradient required for natural acclimatisation.

   • Degradation of downstream fisheries.

2. Topographic changes altering the environment through inadequate dilution of pollutants

   • Pollutant lethal toxicity kills the fish at some stage of its life history.

   • Pollutant sublethal toxicity either preventing the completion of normal life cycle or affects growth and behaviour.

   • Pollutant cumulative effects rendering fish either unsafe or unpalatable for consumption.

3. AQUACULTURE IMPACTS ON ENVIRONMENT AND METIGATING ACTION

3. IMPACT OF AQUACULTURE ON ENVIRONMENT

4. General Remarks

Aquatic resources are valuable assets that should be utilized on a sustainable basis. Any activity whether it is up in the mountain or in the deltaland or in the estuary or in the deep ocean all affect ultimately the aquatic ecology of flowing rivers or still ponds or stagnating estuaries. Infact, indiscriminate logging as developmental activities in upland areas may bring large economic benefits and increase to Government revenue but are harmful to low land activities as fisheries, aquaculture and others. Similarly indiscriminate cutting of mangroves for aquaculture and fuel wood etc. may result in temporary gain in fish production and fuel supply but losses in nursery areas of commercially important fish and shrimp and coastal erosion would adversely affect the biodiversity.

Unfortunately, the present rate of growth in fisheries production is considerably less than the increase in demand. This gap stimulates intensification of fish culture without much concern of water quality, and leads to greater pressure for over fishing in capture fisheries resulting in damaging ecological systems. Fisheries stocks in openwater have limited yields and access to the stocks is open and free. As long as average revenues are greater than average catch, additional fishermen and boats will enter and damage the stock through over fishing. Similarly, destructive fishing like ‘Jatka fisheries’ and wild seed collection of shrimp have serious effects on near shore fish stocks.

The delicate balance between marine life and coastal habitats needs to be appreciated. Over exploitation of the near shore marine living resources is a major concern. Effects on the ozone layers, climatic changes, the green house effects can no longer be ignored. Biodiversity which is the very foundation of biological productivity is at stake. Neither the base for a national food security systems nor the challenges of potential changes in climate can be faced if genetic wealth are not conserved and utilized judiciously.

The whole situation becomes much more complex in this country since many development projects have been initiated and in some cases completed with little access to scientific informations about fish and fisheries resources and also of socio-economic informations of those who are undertaking fisheries. While the aquatic bio-diversity is in peril, the role of importation of fish genetic resources from other countries/ geographical regions, is uncertain. Unless corrective measures and mitigating actions are taken in time on scientific basis the “short term gain” of many development projects may end up with “long term pain”. The country needs to get prepared for contingency plans for mitigating adverse effects.

IMPACT OF INTENSIVE SHRIMP CULTURE ON ENVIRONMENT

Dr. Mahmudul Karim
Consultant

SALIENT POINTS

1. TYPES OF SHRIMP FARMING

1.1. Extensive/Traditional culture

• Pond size varies from a few hectares to over 100 Ha
• Tide fed
• Natural Stocking + some suppl. stocking,
• No pest control screening, or if screening is done, it is only nominal
• Mostly shallow water depth 30–60 cm,
• No liming, fertilization and feeding,
• Some water exchange during spring tides

1.2. Improved extensive culture

• A few to well over 50 Ha ponds, tide fed; some small ponds on higher elevation are pump fed,
• Pre-stocking liming and fertilization
• Better pest control screening,
• Selective stocking 1.5 –3/m²
• No feeding or only low irregular feeding with rice bran, wheat bran, or other feed
• Water depth 60–100 cm,
• 50% water exchange during each spring tide cycle or 5–7 cm water exchange every alternate day by pumping in the case of raised ponds
• Production upto 600–1,000 kg/ha/yr in two crops or 300– 500 kg/ha in areas where culture of two crops not possible

1.3. Semi-intensive culture

• Pond size 0.4 – 5 ha; mostly or wholly pump fed,
• Pest control screening more or less perfect,
• 10–35 fry/m²
• Grow mostly on high quality peleted feed, but partly on natural food organism,
• Water exchange 10–12% daily : gravity drainage, but replenishment by pump,
• Artificial aeration,
• Production 2,000–6,000 kg/year.

1.4. Intensive culture

As in semi-intensive farming, but

• Pond size 0.1 - less than 5 ha,
• Stocking more than 35 per m²
• Grow completely on artificial feed,
• Waste removal more efficient,
• Longer aeration,
• At least 30% water change daily; pond clean-up faster than semi-intensive
• Production 5000–10,000 kg/ha/year.

1.5. Super intensive culture

• Tanks/race ways often indoor,
• Completely on artificial feeding,
• 100% or more water exchange daily,
• 10,000–100,00 kg production,

Thus so far intensive and super-intensive shrimp farming have achieved only marginal success. Generally they have problems with diseases, water quality and environment. Higher level of the stated semi-intensive culture has also suffer with the above problems.

2. Culture Status in Bangladesh

2.1. Above 108,000 Ha under shrimp culture producing about 20,000 mt of shrimp

2.3. Semi-intensive Culture in Bangladesh

3. Risk of Semi-intensive/intensive culture Explain experience in Taiwan

3.1. - Disease and mass mortality

Disease (Taiwan is a classic example)

1. Virus : Penaeus monodon type Baculovirus (MBV)

   • Increased from 15–17% in 1984–86 to 80–85% in 1988 in PL. and juvenile in 1988 : 50% brood stock had MBV infection

   • Slow growth and less resistance to environmental stresses particularly in the case of PL and juveniles

2. Bacteria : Vibrio harvei 4.3%, V. damela 17%, etc.

   • Major cause of mass mortality

   • Abnormality and necrosis of hepato pancreas

   • Vaccine : Vibrio vaccine offer significant protection against V. harvei

3.2. - Degradation of pond soil and water

3.3. - Stunted growth

3.4. - Excessive demand on postlarva, price hike of postlarvae Impact on wild fry and marine catch.

3.5. - Feed

• Fish meal present supply
• Future source ?
• Import or intensify catch of marine trash fish

3.6. Soil quality

• Higher contents of Amonia nitrite and Hydrogen sulphide in the pond result in mass mortality of shrimp.

AFFORESTATION AND THE NUTRIENT SINK

Abdul Bari
Conservator of Forest
Central Circle, Dhaka

1. Back ground information on Forest Resource:

Forest lands account for almost 17% of the geographic surface of Bangladesh. The country has got only about 10.1% (1.46 million ha.) of the land area under the management of the Government Forest Department. There is another 5.1% (0.73 million ha.) of denuded state owned forest land in the eastern hilly region known as Unclassed State Forests (USF) controlled by the civil administration. Still another 1.8% (0.27 million ha.) of the land area constitute the Village Forest growing mostly on the homestead land around dwelling houses in the countryside owned by individuals.

Forest lands under the management of the Forest Department are primarily located in the south east and south-west regions of the country. The densely populated central and northern parts have very low forest land area.

On the basis of forest type and its occurrence, the Forest land administered by the Forest Department can be categorized into four type viz. (a) Hill forests (b) Natural mangrove forests (c) Man-made Mangroves and (d) Inland sal forests.

A tabular statement showing the situation, major tree species and the area of these four forest types occurring in the country is furnished below;

2. Afforestation/Reforestation :

The natural forests are composed of heterogeneous species having low yield and poor quality timber. Of the several hundred species growing, only about 40 species are presently commercially important. Bamboo, sungrass etc. are other important minor forest produce of hill forests which are in great industrial, commercial and household demands. So the natural hill forests are being replaced by plantations of valuable and fast growing species of indigenous and exotic origin.

Forest plantation was first started in this country as far back as in the year 1871 in Chittagong Hill tracts and was expanded outside Hill Tracts after 1920. In 1974 Forest Department began establishing plantation of fast growing species. The total plantation area raised in the country upto 1990–91 is 2,56,300 ha. of which 1,13,000 ha. are coastal plantations 21,100 ha. in sal forest zone and the rest is in the Hill forests.

Coastal plantations provide environmental protection against cyclone & tidal bore, stabilize the fragile coastal soil & make the newly accreted land suitable for agriculture, besides meeting the timber and fuelwood requirement.

3. Plain Land Forests :

Plain land forests covering 0.12 million ha. are located in the central and extreme northern districts. These forests are scattered in nature and intricately mixed with cultivation and habitations. The inland and forests are beset with the problems of serious encroachment and denudation.

These forests were originally owned by a number of landlords and due to over exploitation for a long period of time the crop has become highly depleted and degraded. Because of the serious depletion of the crop under landlords, the management of sal forest was vested with the Forest Department in 1925. These forests were subsequently acquired by the Government under the State Acquisition and Tenancy Act, 1950. These forests are now managed by the Forest Department.

These degraded sal Forests are now being planted up by fast growing valuable species to cover up the barren areas in the shortest possible time.

Apart from plantation in the forest land, since 1980 more than 8,000 k.m. of strips along roads, railway tracks and embankments have been afforested by the Forest Department under three different projects.

NGO's are also now a days engaged in planting such strips specially along council roads with food assistance from WFP and technical assistance of Forest Department.

4. MANGROVE ECOSYSTEM AND FISHERIES PRODUCTION AND DEVELOPMENT:

It is well known that mangrove ecosystem offers nursery ground for various estuarine and marine fishery resources. The Sundarbans and man-made mangrove forest in Bangladesh constitute outstanding examples of ecosystems performing this function.

Aquaculture which is fast developing in the neighborhood of Sundarbans depends by and large on the continuous supply of fish and shrimp fry for stocking. The fertile waters of mangrove serves as nursing ground for fry and juveniles of cultivable species. The strategic functions of mangrove ecosystem is not only providing the nursery ground for post larvae and fry but also growing area for juveniles of finfish and shrimps until they are ready to return to sea to repeat their life cycle. Therefore it is important that mangrove should be preserved to sustain fisheries resources of estuary and near shore.

5. PRODUCTIVITY SOURCE AND SINK PARADIGM IN THE MANGROVES :

Mangroves are amongst the most productive ecosystems as compared to the inland forest ecosystem. Their high productivity is attributed to the production of large wood biomass and litterfall that contribute to the high productivity of the adjoining aquatic ecosystem. Mangrove swamps are continually exchanging tidal waters with adjacent estuaries and other coastal waters. This exchange process involves cycling of nutrients and organic material among various pools, or standing stocks. This cycling includes pathways such as litter production, remineralization and various chemical transformation.

Table showing Comparison of mangrove litter fall estimates from various studies

Mangroves during their photosynthetic process and associated metabalic activity result in a continued recombination of mineral elements into organic compounds such as cellulose, starch, lipids, proteins and vitamins. These elements are stored and partitioned in above the ground and below the ground biomass and released to flooding waters in the form of litterfall. The organic compounds and the minerals are released into the system when the plant parts are decomposed.

The process of decomposition is much more complex. Litter is decomposed by both biological and physical action. Fungi and bacteria are primary biological agents in litter decomposition. The enzymes of these microbes breakdown the structural materials of the litter and this leads to disintegration, consequently the detrital particles are composed of decomposing plant tissue with microbial organisms. These particles are richer in protein, nutritively valuable carbohydrate which acts as base for a complex aquatic foodweb.

It is shown that litter production of different mangrove forest type are different. The same type of forest with different stand densities and biomass, yield different amounts of litter production as shown in the attached table.

Qualitative accounts of dissolved organic matter derived from mangrove is one of the least studied subjects. The available informations indicate that dissolved organic matter leached from the mangrove detritus are mainly low molecular weight carbon. Tanin and lignin like compounds are known to be abundant in leachates.

It has been documented in a number of studies that mangrove swamps play as exporters of organic material to the adjacent estuary. It is estimated that about 50% of the aboveground productivity of a mangrove swamp in south western Florida was exported to the adjacent estuary. From 33% to 60% of the total suspended organic matter in the estuary came from Rhizophora. About 420 g c m, -2-1 yr has been estimated for a mangrove forest in Australia. These estimates establish the fact that many mangrove wetlands are important source of detritus for the adjacent aquatic systems which is important for the fisheries resources.

While mangroves appear to be important exporter of organic material, recent studies have indicated that mangroves may be a nutrient sink. It has been shown that nutrient concentration in waters moving through a mangrove in Hawaii decreased in concentration. Studies in Malayan mangrove indicated that dissolved nitrogen in the form of ammonia can be high at the upstream with rapid decrease in concentration down the estuary towards the sea. These may be taken as an indication that the mangrove ecosystem acts as a sink for ammonia nitrogen. Nitrogen in the mangrove environment is being removed from the dissolved nutrient pool through assimilation and incorporation into microorganisms, e,g. phytoplankton and bacteria or get immobilized by other chemical means thus removed from the soluble nutrient pool. Total phosphorus also behave like ammonia in the system with higher concentration at the upper boundary of the mangrove and decreases in concentration down the estuary, indicating that for phosphorus the system acts as a sink.

From the above facts it is obvious that the behavior of particulate matters and nutrients in the mangroves and the adjoining aquatic system is not a simple one. Both organic matter and the nutrients that are being leached into the aquatic system adjoining the mangroves are subjected to a complex chain of dynamic interchange. Each element has its own cycling pattern, its own inputs, outputs, transformation and storage mechanism depending on the prevailing conditions that exist at the moment of time and space. The question as to whether mangrove act as source or sink will thus depend on the behaviour of the concerned element in the whole system. Scientific management of this requires adequate understanding of the complex functioning of this ecosystem.

In sea & coastal area waves, tides, currents, salinities, temperatures, pressure and light intensities largely determine the make up of biological communities that, in turn have considerable influence on the composition of bottom sediments and gases in solution. Salinity and temperature are much more variable near the shore than in the sea itself. Food conditions are so much better that the region is packed with life. Phytoplankton, benthic microflora & macroflora are often intermixed in an estuary and often an efficient nutrient trap and acts as nursery ground for most coastal shellfish and fishes that are harvested not only in estuary but offshore as well.

The nutrients/minerals that are taken up into forest trees are eventually returned to the forest soil except for the amount carried out of the forest in the from of logs and other forest products. Nutrients are returned to the surface of the soil by litterfall and through washing and leaching effects of rain on tree foliage and stems. Minerals are also added by the dying and sloughing of roots.

Afforestation programme is normally under taken in the newly accreted Char lands. Establishment of mangrove forests provide productive & protective ground for fishes. As the sun is the main and ultimate source of energy, this energy is trapped by trees and autotrophic plants, which inturn makes the energy available for animal kingdom. So afforestation in the coastal areas expedite the natural process, and creates nutrient pool for varieties of fishes & other marine life.