Survey of capture fisheries in the Koshi River basin. (by S. Yadav)

Fisheries Training Centre Janakpur (FTC), Dhanusha, Nepal

ABSTRACT

The Koshi River has a vast catchment area varied in nature, draining the high altitude Himalayas covered in permanent ice, entering mid hills, to eventually discharge itself onto alluvial plains of lowlands. The study site lies within 86°55' - 87°05' E longitude and 26°24' - 26°45' N latitude, on the alluvial floodplains of Sapta Koshi. Ninety-six species of fish were identified during the study period of four months. Of these, 11 species are very common. Fishermen use more than 15 types of fishing gear to catch the fish. The catch per unit area is estimated as 1.14 kg/ha/day in the Koshi River (1.2 km times 4 km) while in the other water bodies it is 3 kg/ha/day. Observations have shown that fish yield from the Koshi River has not been commensurate with the productivity of the system and certain stretches have been subjected to intensive exploitation. The fishermen belong to a number of ethnic groups such as Godhi, Mallah, Mukhiya, Bahardhar. There are ten main villages of fishermen. The total population is estimated to be 2 937 in 484 households in all ten villages, of which 445 households are solely dependent on the fishing while the rest of the families have switched from the traditional occupation to agriculture, rickshaw pulling, working as carpenters and field labourers. 133 families other than traditional fishermen, especially Muslims, have been found to be attracted to the fishing. The fishermen communities in all ten villages of the Koshi basin have similar social structure, with minor variations in caste titles and living styles. All of them depend basically on the capture fishery. The socio-economic status of the fishermen communities is the lowest in the society. 46% families were found to be landless while 54% of the population owned less than 0.2 ha of land. 93% respondents earned less than NRs. 5 000 per annum and 7% NRs. 5 000 - 10 000, while none had more than NRs. 2 000. Improving the social status of the fishermen communities is urgently needed, but among the major problems figure prominently the disturbance in the catchment and overfishing, both of which require urgent attention.

1. BACKGROUND

Nepal is a landlocked country between India and China. It extends from 26°30' to 30°15' N and from 80° to 88°15' E. In the north are the ranges of the Himalayas, with the highest peak at 8848 m, and in the south the humid hot Terai plains. This tremendous altitudinal difference produces great biological variations, including a great variety of fish in Nepal's 6 000 rivers and streams, lakes and swamps. Water bodies cover about 3% of the total land area of the country.

Koshi, Gandaki and Karnali are the principal river systems fed by hundreds of small rivers and streams originating in the Mahabharat and Siwalik mountain ranges. Snow and glacial melt from the Himalayas continuously feed these rivers, augmented by rainfall runoff, particularly during monsoons.

The waters of Nepal provide a variety of habitats for indigenous fish, water for irrigation and for hydropower generation.

2. FISH AND FISHERIES

Koshi is the largest river of Nepal, with the largest catchment area. This river is formed by the rivers Indrabati, Tama Koshi, Likhu Khola, Sun Koshi, Dudh Koshi, Arun and Tamor. Another large river is Sapt Koshi, with a catchment of approximately 60 000 km², 55 percent of which lies in Nepal and 45 percent in Tibet. About 10 percent of the catchment is covered with ice and snow. The climate of the river basin is of monsoon type with a mean annual rainfall of 2 110 mm, mean maximum air temperature of 37°C, and a mean minimum temperature of 8°C (Scott, 1989, as cited in the Woodlands Mountain Institute and IUCN/Nepal, 1994).

2.1 Capture fisheries

Fisheries has been an important occupation in many parts of Nepal. In spite its significance and the institutional efforts the contribution of fisheries to employment, national income and exports has been far from satisfactory. Government fisheries institutions have been able to make estimates of fish catches in some fresh waters and have studied the people involved in it.

Capture fisheries in Nepal is widely scattered and not organized. Scanty records are available on capture fisheries. However, in view of its fisheries importance, preliminary surveys of a number of water bodies have been carried out by the Fisheries Development Directorate to assess the level of capture fisheries (Table 1). As Nepal is a landlocked country, capture fishery has an important role. In 1998 it was estimated that 204 000 people were actively involved in capture fisheries. Most of them were living scattered along the rivers and lakes and were not organized or supported. The communities used traditional fishing gear for subsistence fishery, generating marginal economic benefits. Destructive devices such as dynamite, fish poisons, electrofishing, etc., were common, having a negative impact on fish by destroying broodstock, spawning and nursery grounds.

Table 1

Water resources and capture fish production (FDD 2000/2001)

Table 2

Families involved, active members, beneficiaries and value from capture fisheries

(Matsya Palan Srinkhala - 5, 1999)

In Nepal about 51 000 traditional fishermen families as well as others are involved in culture fisheries, with total active members of 204 000 (Table 2). This represents nearly one percent of the total population of Nepal, contributing 0.81 percent to the national GDP. The national records of capture fisheries show that the production is increasing per unit area, but the rate of increment is very low (11 kg/ha/yr and 12.5 kg/ha/yr in 1997/98 and 2000/01, respectively). The increment per unit area is the effect of a higher fishing intensity.

2.2 Constraints

Observations have shown that fish yield from the Koshi River has not been commensurate with the productivity of the system and certain stretches have been subjected to intensive exploitation. The river fisheries range from localized subsistence fishing to highly mobile and intensive operations (Srivastava and Vathsala, 1984). The intensity of fishing, nature of exploitation and species-orientation are governed by an array of factors such as

• seasonality of riverine fishing activity;

• unstable catch composition;

• conflicting use of river water;

• lack of understanding of the fluvial system and poor data base;

• inadequacy of infrastructure and supportive services to the fishermen;

• socio-economic and socio-cultural determinants.

It is therefore evident that a number of diverse and complex problems confront the fishery of the Koshi basin. The constraints have wider dimensions and can be broadly grouped under four major categories.

2.2.1 Biological constraints - In the Koshi basin fisheries are affected directly by recruitment and age structure, and indirectly by ecosystem, influenced by food supply and habitat alteration. In a fluvial system, the biological productivity is governed by primary production, thermodynamics of the eco-system and exchange of organic matter. The nature of flood regime is one of the most important parameters influencing the riverine fisheries. In the Koshi River frequent changing of fluvial features largely determines the success of breeding of most of the important species and affects the migratory fish. There is a need for a more profound studies of fish population dynamics.

2.2.2 Environmental constraints

The deleterious effects of dams, weirs and barrages on river fish species are well known. The Koshi river basin has experienced changes due to the construction of several structures, of which the Chatara irrigation canal and barrage near the Indo-Nepal border has affected migration and breeding of important species. The increasing human immigration from other parts of the country has a negative impact on the riverine environment of the Koshi River.

2.2.3 Socio-economic constraints

Fishing in the Koshi River has been an age-old source of livelihood for thousands of riparian fishermen. They are more apt to have the traditional social structure suited to existing conditions. They manage their every social need by fishing and marketing the catch. To introduce new and suitable management is socially difficult. The cultural values are so firmly established that any change in this superstitious, educationally-backward fishing community will run up against accepted social habits, belief and attitude. However, such barriers can be surmounted through a rational programme of extension, education and training.

2.2.4 Legal constraints

Despite legal prohibition (Jalchar Ain, 2017 B.S.) indiscriminate capture of spawners and juveniles and destructive fishing practices of dynamiting and poisoning the water bodies have been going on due to lack of awareness. Fishery regulations have played a subordinate role since they have been ineffective, mostly due to enforcement problems and difficulties in subsequent monitoring of the activities.

3. PRESENT STUDY

The paper addresses the following main objectives of the study:

- fish yields in the Koshi River;

- revision of the checklist of indigenous fish of the Koshi River and other water bodies in its basin;

- the fishermen community and the social structure, and

- the status of the ecology of the Koshi river basin.

The usefulness of the work for the purpose of planning and designing for further development of the river basin has been the primary objective.

3.1 Study site

Since the Koshi basin includes a vast area along the river in the plains as well as seven catchment rivers feeding the Sapta Koshi, it was not possible to conduct a study of the whole basin. The study was therefore limited to the river between Tribeni and the Indo-Nepalese border (Bhimnagar barrage). The Koshi River receives seven major rivers - this is why it is named Sapta Koshi. These are: Indrabati, Tama Koshi, Likhu Khola, Dudh Koshi, Sun Koshi, Arun and Tamor.

The study site is the major part of the Koshi Tappu Wildlife Reserve (KTWR), a rich Nepalese wildlife natural reservation famous for wild water buffaloes (Bubalus bubalis). The study site lies within 86º55' - 87º05' E longitude and 26º24' - 26º45' N latitude, on the alluvial floodplain of Sapta Koshi. Increasing difficulties faced in sustainable biodiversity conservation led the Ministry of Forest of the HMG of Nepal and UNDP to initiate in 1995 the Park and People Programme (Nikunj - Janta - Karyakram) (PPP, 2000). The programme aims to prevent the people interfering with the wildlife area. The programme helps the people by providing soft loans, short-term training, exposure visits and other technical support through group mobilization and saving and credit systems. Presently, fifteen ponds of around ten hectares in area have been constructed in the wetlands and operated successfully with good returns.

3.2 Ecological features

The ecology of the surface runoff waters plays the most important role and determines the flora and fauna in the different sections of the river. The Koshi River has a vast catchment area varied in nature, with the high altitude of the Himalayas, hills, and alluvial deposits in lowlands. With the increase of the volume of runoff water and the slope gradient, erosion also becomes faster and consequently the channel becomes larger and carries more runoff.

In the Koshi River basin forest, agriculture lands and aquatic environment interact, which results in a complex ecological network with a substantial impact on the fish fauna of the river. The large number of cows and buffaloes interacts with the river water by supplying nitrogenous waste. Likewise the forest ecology enriches water with organic matter and products of its decomposition.

3.2.1 Physico-chemical parameters

Due to the high precipitation, in its upper and middle courses the river has a torrential flow. Further downstream, near the Indo-Nepalese border, the current velocity decreases. Higher silt due to the upstream soil erosion also retards the velocity of flow. The silt records at the origin of the Chatara Irrigation Canal showed that the highest suspended load of 2 277 g/L was carried in August 1999, while the minimum of 1 g/L was in December 1999. The water temperature ranged from 17 to 24°C, with a very narrow range in the upper course as compared to the lower course. Dissolved oxygen ranged from 7.5 to 9.0 mg/L, being higher in the upper course while lower in the lower course. The pH ranged from 8.0 to 11.5, alkalinity from 69.0 to 85.5 mg/L, and hardness from 130.3 to 136.9 mg/L.

3.3 Fish and fisheries

The Koshi river basin in the Nepalese lowlands plays a vital role and constitutes one of the principal sources of fish. The study concerning fish fauna in Koshi basin is meager. Rajbanshi (these proceedings) listed 75 species for the Koshi River. The author, as per interviews through questionnaires and discussions with fishermen at different fishing sites, mallaha's village, vendors and the fish sellers, found 93 species.

3.3.1 Fishing methods

Fishing in the Koshi River changes with the season and the location. It is very diffused. Most of the fishermen use a small wooden canoe. Canoes made of sal wood last longer than those made of siso wood. Most fishermen use canoe and cast net while the use of canoe and drag net is the second most common method.

A number of fishing devices are used. These are: cast nets, gill nets, lift nets, and various other nets with indigenous names, such as tunny jal, chatti jal, chauki or chanki jal, sohat, hapa, different types of traps, baskets, rod and line. Poisoning, bombing and hand picking are frequent.

One of the several traditional methods is the use of extracts from local plants as fish poison. In the Koshi basin in lakes, swamps, streams and oxbows the plants Agave americana, Sapium insinge, Dioscorea deltoidea, Euphorbia voyelana are, as reported by the fishermen, commonly used.

3.3.2 Catch per unit of area and catch records

Catch statistics from the Koshi River are based on interviews with fishermen and personal observations. Due to the difficulties of collecting data from fishermen who operate from many sites along the river the catch per unit area is computed by taking a total average weight of the catch per fisherman, from which the catch per unit area is calculated. The effort made by the craft used, tackle and fishermen population in the entire region was considered as uniform. The illiteracy and social backwardness of the fishermen community also greatly hampered the collection of the data. The catch per unit area is estimated as 1.14 kg/ha/day in the Koshi River (1.2 km times 4 km) while in the other water bodies it is 3 kg/ha/day.

3.3.3 Fisher community

The fishermen community is commonly understood as a group fishing in some area and engaged in more or less the same pattern of fishing (Biswas, 1996). In such a community, fishermen often mutually assist each other, not only in fishing, but also in social functions such as marriage ceremonies and village festivals. The river basin is rich in cultural heritage with various ethnic groups, predominantly Yadav, Muslim, Brahmin, Chhetri and other castes of low profile. Fishermen community, also called Mallah, Godhi, Mukhiya, Bahardhar, Bin, etc., are the poorest among the poor and scattered.

During the visit, the random sampling was done in the traditional villages. There are four main villages of fishermen in Sunsari District and six in Saptari District (Table 3). The total population was estimated to be 2937 in 484 households in all ten villages, of which 445 households are solely dependent on the fishing while the rest of the families have switched from the traditional occupation to agriculture, rickshaw pulling, working as carpenters and field labourers. 133 families other than traditional fishermen, especially Muslims, have been found to be attracted to the fishing.

The fishermen communities in all ten villages of the Koshi basin have similar social structures, with minor variations in the caste titles and living styles. All of them depend basically on the capture fishery. The socio-economic status of the fishermen communities is the lowest in the society. Eighty-six percent of families of the fishermen were of nuclear type and 75% of families had 5-10 members. Age distribution data show that the economically active group represents only 29% and they support the rest of the family members by fishing. Even if those in the 11-20 year-old age group, who are considered dependent, is taken into consideration, 52% of the population has to support the rest. The high population growth rate in this society is associated with the lack of awareness of family planning. Family planning activity is related to educational status and in the fishermen communities 61% of the population is illiterate while only 3% had the School Leaving Certificate. The most striking situation in the communities was the land holding capacity, a prestige symbol in Nepalese society. Forty-six % of families were found to be landless while 54% of the population owned less than 0.2 ha of land. Eighty-nine % of fishermen owned only traditional fishing nets and gears and 43%, 38% and 14% fishermen had bicycle, radio and television, respectively. No cattle were owned by 43% of respondents while only 39% owned a goat and 18% owned cows. Ninety-three % of respondents earned less than NRs. 5 000 per annum and 7% NRs. 5 000 - 10 000.

From the socio-cultural point of view they are maintaining the same social activities as their ancestors, but every activity is firmly connected with the river and catch. Illiteracy, high population growth, low risk bearing capacity and unskilled youth in the community bind them to go on with their traditional occupation even if it is no longer beneficial.

Table 3

Fishermen population in different VDCs of Koshi basin

3.3.4 Fishery resources

Through interviews and discussions with fishermen it appears that the fish stocks in the Koshi River have decreased considerably. Some species have become rare while others have disappeared. The reasons are: overfishing, high population pressure along the river banks, entry of other castes into fishery, use of improper and illegal fishing gears and methods, heavy floods and siltation, habitat degradation, erosion, impact of the Koshi barrage, degradation of environment. Some of these factors have disturbed or damaged the fish habitats, especially spawning and nursery grounds. Monitoring of the average catch per month of some commonly found species for three months showed that Garra gotyla and Labeo boga represented the first and the second most common fish captured during winter. The fishermen reported that after rains the catch composition changes and Cirrhinus reba and Labeo rohita become the major catch. With commencement of the rain fish migrate upstream for breeding and the spawn drifts with the water current downstream where there is richer planktonic food. Once the rain is over, the juveniles migrate upstream in large groups and this lasts for about a month. Thus the fish movement in the river system is a continuous process and fishing is changing with time and seasons. Consequently, broodstock and juveniles are also targeted.

3.3.5 Human intervention

The high growth rate of human population has resulted in immigration and settling of more people in the area. The alluvial fertile soil along the river has attracted people as well. During the last two decades the water of the Koshi River has been subjected to a wide range of stress factors caused by human activities directly or indirectly. Indiscriminate deforestation, dams and water diversion for irrigation, improper fishing practices, disposals of city effluents and use of chemicals for different purposes, with residues ending in rivers, have had a damaging impact on the river fish. Siltation has resulted from deforestation and conversion of forest land into agriculture land. Road construction, especially on steep slopes, has also caused soil erosion in the monsoon period. Lakes and swamps receiving river water loaded with sediments are silting over.

3.3.6 Dams and reservoirs

There is only one dam on the Koshi River, which was constructed at the Indo-Nepalese border. It has a fish ladder which is known to be inefficient for migratory fish. The reservoir has been undergoing sedimentation, and deep layers of sediment are exposed by seasonal drawdown.

4. RECOMMENDATIONS

The Koshi River is a unique ecological zone from the point of view of biological importance. It has a large and varied topographical diversity which harbors unique fish fauna. To preserve it and to use it in a rational way the following activities are proposed:

• detailed survey of the fish fauna in the catchment water bodies with the purpose of updating the knowledge about the basin,

• immediate ban on deforestation, sand and boulder removal from the river bed, on illegal settlements along river banks and on other activities damaging the riverine ecology,

• reforestation of steep slopes in the catchment in order to arrest the land erosion.

The government, NGO, INGO should take over the responsibilities for improving the social status of the fishermen communities by uniting them in groups or cooperatives, and providing them with informal education through training with special reference to fish and riverine fisheries in order to develop and conserve this precious natural resource. Area-based riverine fishery development projects should be started. These projects should integrate the whole fishery system including extension, training, research and marketing. Development of fisheries in wetlands through public as well as private interests, using community mobilization, would help to establish a buffer zone between the conservation and agriculture lands and prevent interaction between wild animals and people. The programme should be initiated with a proper model by the government to demonstrate its feasibility to the community.

References

Biswas, K. P., 1996. A Textbook of Fish and Fisheries and Technology. Second Edition.

Matsya Palan Srinkhala - 5 1999. Proceedings of the National Workshop on the "Prospects of Fisheries Development under the Agriculture Perspective Plan". Nepal.

PPP, 2000. Annual Report 2000. Consolidating Conservation through People's Participation. HMG Department of National Parks and Wildlife Conservation and UNDP. Nepal.

Srivastava, U. K. and Vathsala, S., 1984. Strategy for Development of Inland Fishery Resources in India.

Wooodlands Mountain Institute and IUCN/Nepal, 1994. Biodiversity of Koshi Tappu Wildlife Reserve and its Adjacent Area. Published in Kathmandu, Nepal.