This paper deals with the status of fish, fisheries, and habitats in Nepal. Being a landlocked country, it has only freshwater habitats covering an area of 745,000 hectares (5% of the total area) that includes rivers, lakes, ponds, wetlands, reservoirs, and irrigated rice fields. It has a diverse fish species totaling 200 fish species, of which 191 are indigenous and nine exotic. Thirty-four fish species were categorized as threatened (IUCN categories), requiring due attention for the conservation. Legal protection is recommended for ten fish species in the endangered and vulnerable categories. Fish harvests are mainly based on the subsistence fish farming, and from capture fisheries. National fish production in the year 2000/01 was 33,270 metric tons. Lowland areas are most suitable for aquaculture, whereas hill streams have a great attraction for sport fishing. Some destructive fishing methods are in use in capture fishery, e.g., electric fishing, explosives and poisons. In Nepal, some of the major fish habitats are in protected conservation areas, e.g., national parks and World Ramsar Sites. However, proper consideration has not been given for fish habitat management. The national plan includes a fisheries/aquaculture sub sector mainly for supplying animal protein, and for generating self-employment and income of small-scale farmers. The number of people involved in the capture fisheries has increased and included 142,000 men and 223,000 women in the year 2000/01. At the same time, commercial trout farming in the private sector has increased. Long-term perspectives in the fields of aquatic ecology, genetics, biotechnology and ecotoxicology are essential to enhance the fish and fisheries science in the country.
[Supplementary material is available for this article. Go to the publisher's online edition of Aquatic Ecosystem Health & Management for the following free supplemental resource: an appendix containing a checklist of freshwater fishes of Nepal.]
This paper describes the freshwater fishes of Nepal and their ecology, including the status of fisheries in the country. The main objectives of the paper are therefore:
✓ Report on the fish diversity and freshwater resources of Nepal,
✓ Analyze the present status of fish and fisheries in Nepal,
✓ Ascertain the state of freshwater fish habitat management, and,
✓ Identify the priority gaps and needs in freshwater fishery science
Nepal is a small landlocked country in south Asia located between China in the north and India in all other three directions (26° 22′ to 30° 27′ N and 80° 4′ to 88° 12′ E), with an area of 147,181 km2. The altitudinal variation of the country ranges from 70 m above sea level (asl) to the world's highest peak, Mount Everest (8,848 m asl). The southern part of the country has a lowland belt called the ‘Terai region’, with a tropical/subtropical climate (17%), the middle belt contains hilly region, with rugged terrain having temperate climate called ‘midhills’ (68%), and the northern belt contains very high snow-clad mountains representing the alpine climate, which is a part of Hindu-Kush Himalayas (15%) (Amatya and Shrestha, 1967). Therefore, the country has diverse climatic conditions over very short distances (south to north), due to influence of the altitudinal variations and its location in sub-tropical latitudes, which help to harbor high biodiversity.
Being landlocked, Nepal has only inland water resources including the river systems (Figure 1), lakes, reservoirs, village ponds, wetlands, and irrigated rice fields totaling 745,000 hectare of water surface area (Amatya and Shrestha, 1967; Pradhan and Pantha, 1995). The water bodies cover about 5% of the total area of the country. The estimated water surface area in Nepal is in Table 1. Natural water resources including rivers, lakes and reservoirs comprise approximately 54%of the total water bodies (Table 1).
Freshwater fish fauna
The fishes of Nepal are very similar to those of Southeast Asia, consisting mainly of carps, catfishes, sheatfishes, featherbacks, eels, and hill stream fishes. The lowland Terai is home to more than 100 species of fishes, with decreasing species richness as the altitude increases. The midhills region is the habitat for many sport fishes. The high mountainous region contains few species of small sized fishes. A checklist of 191 indigenous fish species has been compiled in this paper based on the various published literature. In addition, nine exotic fish species have been introduced in the country to increase the fish production, making a total of 200 fish species (appendix 1: availabe at www.aehms.org/Journal/11_3_Sharma_appendix.html).
The size diversity of the fishes is great, with the largest fish, Sahar (Tor putitora), recorded at 45 kg with a length of 1.8 m and the smallest fish, Zebra danio (Danio rerio), being just 26 mm in length (Shrestha, 1994). Some authors have also mentioned that the largest fish recorded was Gounch (Bagarius bagarius) that weighed 80 kg (Shrestha, 2002).
Mainly subsistence fish farms exist in Nepal. Fisheries is not a big industry; however, it has been increasing at a rapid pace recently. Both capture fishery and aquaculture have been practiced contributing about 50% by each category (Figure 2). National production of fishes in the year 2000/01 was 33,270 metric tons (Figure 2). The main government body managing the fisheries and aquaculture development in Nepal is the Directorate of Fisheries Development (DOFD) under the Department of Agriculture. Both indigenous and exotic fish species are reared in fish ponds, reservoirs and lakes, whereas indigenous fishes dominate in the capture fisheries in rivers and streams (Gurung, 2003).
Traditional fishing methods are used by most of the subsistence farmers, e.g., nets (cast nets, gill nets and scoop nets), fishing rods (hook-line), loops, diversion of river channel and fish spearing. Recently the use of destructive fishing methods has increased, including electric fishing, explosives, and poisons (Shrestha, 1994; Sharma and Shrestha, 1998; Gurung, 2003).
State of freshwater fish science in the country
The earliest record of freshwater fish study in Nepal goes back to 1793 when Colonel Kirkpatrick arrived in Kathmandu, the capital of Nepal, for his political mission and described the fishing methods in the River Rapti of Makawanpur district (Shrestha, 1994). The second published record was from 1822 by Francis Buchanan (later Hamilton), describing fishes found in River Ganges and its tributaries. Talwar and Jhingran (1991) reported 930 freshwater fish species from the Indian Subcontinent including Nepal. Although the numbers of publications related to the fish and fisheries have increased tremendously due to the efforts of scientists and other scholars in this field, they are not sufficiently disseminated. A historical review of the fish and fisheries of Nepal, as described by several authors, can be found in Shrestha (1994).
Few institutions are devoted to the field of fish and fisheries in Nepal. Tribhuvan University (TU), Nepal Agricultural Research Council (NARC), and Nepal Academy of Science and Technology (NAST) are the most important research organizations in fish and fisheries sectors. The efforts of Ministry of Agriculture have contributed significantly in the development of this sector through Fisheries Development Division (FDD). In addition, the contribution of some international organizations, for example, Food and Agriculture Organizations of the United Nations Development Agencies (FAO/UNDP), Asian Development Bank (ADB), Japan International Co-operation Agency (JICA), United States Assistance for International Development (USAID), International Development Research Center (IDRC), and Hill Agriculture Research Program of DIFID (Department for International Development) for financial and technical support for expansion of aquaculture is worth mentioning (Gurung, 2003). Recently, other academic institutions, such as Kathmandu University, have also started contributing to the study of freshwater fisheries.
Although fish distributions in the Eastern (Assam) and Western (Kumaon) Himalayan region have been studied by many ichthyologists since 1822, the region within Nepal has only been investigated widely in recent years by many developmental/educational institutions as well as by individual biologists (Rajbanshi, 2002).
Current state of freshwater fishes
The freshwaters of Nepal harbor a total of 200 species of fishes from 114 genera belonging to 36 families and only 11 orders, e.g., Clupeiformes, Osteoglossiformes, Cypriniformes, Siluriformes, Anguilliformes, Beloniformes, Cyprinodontiformes, Synbranchiformes, Perciformes, Tetraodontiformes, and Salmoniformes. However, the total numbers of fish listed by different authors vary due to some confusion regarding fish genera, species, synonyms, nomenclature and systematic position (Shrestha, 2002). There is also a lack of comprehensive studies on the distribution of the indigenous fish in all habitat types (Rajbanshi, 2002). At present, nine endemic fish species have been reported from Nepal (Shrestha, 2002) where Lake Rara has three species of Schizothorax (Terasima, 1984; Dimmik and Edds, 2002). This number may increase as ichthyological surveys increase in the future. There is also a need of thorough studies on many fish species (Shrestha, 2002).
Cyprinids dominate freshwater habitats in Nepal. The Himalayan region is mainly dominated by schizothoracids, e.g. trouts (Schizothorax spp.; Appendix 1: available at www.aehms.org/Journal/11_3_Sharma_appendix.html) particularly in glacier-fed and snow-fed rivers of upper reaches. The mid-hills are mainly inhabited by a mixed group of fishes, e.g. Cyprinidae, Cobitidae, Channidae, Anguillidae, and Sisoridae etc. The major carps such as Mahseer (Tor tor, T. putitora), Copper Mahseer (Neolissochilus hexagonolepis), and Rohu (Labeo angra, Sinilabeo dero) occurs in the transitional zone between midhills and terai region. The lower parts of the country are mainly occupied by minnows, carps, knife fish, perches, and eels (Shrestha, 2003).
Current status of freshwater fisheries
About 51% of the total fish production in Nepal was achieved through aquaculture in the year 2000/01 (Gurung, 2003). Fishes are cultivated in ponds, cages, pens, rice fields, and raceways. Fish cultivation contributes to the major fish production of the country mostly in the lowland warm areas. The major fish species in these areas are: bighead carp (Aristichthys nobilis), silver carp (Hypophthalmichthys molitrix), grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio carpio), and rohu (Labeo rohita). Mrigala (Cirrhinus cirrhosus) and bhakur (Catla catla) are also used in aquaculture, but to a lesser extent.
Commercial fishery has been practiced in some of the places like Pokhara, Hetauda, Janakpur, Biratnagar, Rajbiraj (Shrestha, 2002; Gurung, 2003) and Bhairahawa, but they have limited supplies and cannot support increasing demand in the country. Some of the remote places like upper Karnali Valley, Kaligandaki, Sunkoshi, Khimti, Chatra and Chisapani are famous commercial fishery centers, but are run on a small scale due to lack of physical infrastructures for the preserving facilities (Shrestha, T.K., 2002).
Current status of freshwater habitats
The water supply of Nepal comes from the snow-clad Himalayas in the north and from glaciers. The rivers and lakes support a vast array of aquatic life, including fish. Little scientific knowledge is available about the physical, chemical (including pollution) and biological features of the freshwater bodies of Nepal (Shrestha, T.K., 2002). Nepal has considerable freshwater resources that can support fisheries if properly managed. The potential sources of inland fisheries include rivers, lakes, reservoirs, ponds, wetlands and irrigated rice fields (Table 1). Reservoirs and the village ponds, totaling 8200 hectares areas, have a great potentiality that can be utilized for fish production in the future (Table 1). However, increasing trend of polluted water bodies, for example, River Bagmati in the capital city of Nepal that does not harbor any fish species in a stretch inside the valley (Sharma, Norwegian University of Life Sciences, Aas, Norway, pers. observ.), can be seen as a threat to the freshwater fishes.
The major river systems of Nepal include Koshi in the east, Gandaki in the middle, and Karnali in the western part of the country. These rivers receive many other tributaries on their way from north to south. Hill streams are little exploited for the sport fishing that could attract many people and support tourism.
Nepal has many medium and small lakes covering about 5,000 ha of water surface area (Table 1). The high altitude lakes are mainly of glacial origin, the mid-hill lakes are tectonic, and the lowland lakes are of ox-bow origin (Bhandari, 1996). The main lakes of Nepal are given in Table 2.
The major reservoirs suitable for aquaculture include Jagadishpur (225 ha), Trishuli (16 ha), Marshyangdi (62 ha), Kulekhani (220 ha) and Gandaki (500 ha) (Shrestha et al., 2002; WWF Nepal, 2007). In addition, some wetlands are designated as World Ramsar Sites, and support a large array of aquatic life, e.g., Ghodaghodi, Jagadishpur, Beeshazar and Koshi Tappu. Recently, high mountain lakes were also included in the World Ramsar Sites, e.g. Rara, Phoksumdo, Gosaikunda and Gokyo (see Table 2 for water body type).
Lakes have been used for cage and pen culture to rear some exotic and indigenous fish species, e.g. Phewa, Begnas and Rupa lakes in the mid-hill region, since the late 1980s (Shrestha et al., 2002; Gurung, 2003). Also, cage culture began in a reservoir called Indrasarobar in Kulekhani in 1985. However, the expansion of the cage culture by private farmers only started in 1993 (Shrestha et al., 2002).
Survey of freshwater fishes management
The researchers from the academic institutions like Tribhuvan University (TU) have been working in this field since the establishment of the Central Department of Zoology in 1960s. NARC has been involved mainly in the fish research in support of fisheries. Fisheries are one of the important sub-sectors of agriculture, contributing about 1.5 percent to agricultural gross domestic product (NARC, 1994). Besides, private institutions, like Kathmandu University (KU), and some freelance human resources have actively participated in this field in recent years. The fisheries sector has been studied and managed by mobilizing the researchers through public institutions like NARC and FDD. However, these institutions have not been able to accomplish a proper management. The lack of harmony that seems to prevail among the academic institutions and the government organizations could be bridged through new arrangements. Fu et al. (2003) and Minns (2001) suggest data sharing and collaboration as essential tools for the effectiveness of fish conservation. Such bridging can be used to foster links between the science and the management of fisheries.
Legislative and regulatory treatment of fish, habitat, and fisheries
The country has a legal framework, the Aquatic Animal Protection Act (“Jalchar Samrachhyan Ain 2017” in Nepali), to protect the aquatic organisms in the country (FAO, 1997). Now, the government has taken active efforts for protecting fish near spill way and tail water of dams through this act (Shrestha, 2003). However, it does not have sufficient or adequate regulations to implement action (FAO, 1997).
There have been studies to identify the status of wild animals and to develop strategies for protecting them. However, attention has not been given towards protection of the fishes of Nepal. Organizations like IUCN and international agreement like CITES provide the official listings of threatened animals, but their Red Book Lists do not include fish species from Nepal (Rajbanshi, 2002; Shrestha, 2003). In an attempt to enumerate the freshwater fishes of Nepal, a total of 34 fish species were categorized as threatened (vulnerable-9, endangered-1 and rare-24) species according to IUCN categories (Table 3; Shrestha, 1995). Shrestha recommended legal protection for ten species in the endangered and vulnerable categories: Tor tor as endangered, and, Barbodes hexagonolepis (Neolissochilus hexagonolepis), Chaguni (Chagunius chagunio), T. putitora, Danio rerio, Schizothorax plagiostomus, Snow trout (S. richardsonii), Dinnawah snow trout (Schizothoraichthys progastus), Psilorhynchoides pseudecheneis, and Indian mottled eel (Anguilla bengalensis bengalensis) as vulnerable.
Some freshwater bodies have been included in protected areas, such as Rara Lake (Rara National Park), Phoksumdo Lake (Shey-Phoksumdo National Park) in the higher mountainous region. Similarly, some of the good fish habitats (wetlands) in the lowlands were set aside as World Ramsar Sites to preserve the habitats for different aquatic animals, mainly aquatic birds: Ghodaghodi Lake Area in Kailali District, Jagadishpur Reservoir in Kapilvastu District, Beeshazar and associated lakes in the buffer zone of Chitwan National Park, and Koshi Tappu in Koshi Tappu Wildlife Reserve (Wetlands, 2005). Although the main reason for protecting these freshwater bodies was not the conservation of fish habitats, the actions will eventually help to protect them indirectly. Some of the major rivers were also included in the protected areas: a section of River Karnali flows through the Bardia National Park and River Koshi flows through the Koshi Tappu Wildlife Reserve, which helps to preserve the natural fish habitats in running waters.
The ninth five-year national plan, starting in 1997/1998, included the fisheries/aquaculture sub sector in agricultural section with the following objectives (FAO, 1997).
✓ Increased supply of animal protein;
✓ Improvement of income and living standard of small scale farmers;
✓ Generation of self-employment in rural areas through fish farming.
Private commercial fish farms for the production of fingerlings and large fishes have been established in many parts of Nepal. This is enhancing the production of both indigenous as well as exotic fish production in the country. A total of 365000 people were engaged in subsistence capture fisheries in rivers, lakes and swamps during the year 2000/01. This indicates an enormous increase in the number of people involved in fisheries when compared to a total of 80,000 people in 1980s (Gurung, 2003).
Linkages with biodiversity conservation and ecosystem management
The biodiversity and ecological roles of fishes in aquatic conservation, ecosystem management, restoration and aquatic environmental regulations are being increasingly recognized all over (Ormerod, 2003). Nepal is provided with a vast array of fish species owing to the diverse geographic realm in a very small area. Although parks and protected areas are very important in conserving wildlife including aquatic organisms, they do not cover most of the important fish habitats in Nepal. Almost none of the water bodies are managed to conserve the fish habitat. The wetlands of lowland Nepal included in the World Ramsar Site are mainly managed to conserve the habitats for migratory water birds (Wetlands, 2005). The same applies in most part of the protected areas in the world, where fish habitats are not the main targets for protection. Many studies have indicated that the establishment of nature reserves to protect the fish biodiversity has become necessary (Fu et al., 2003; Jang et al., 2003). We must determine the role played by fishes in species conservation and include fish habitats within a coherent network, so that they can become a major part of conservation efforts for threatened freshwater fish species (Keith, 2000). The plans for protection of aquatic biota: legal protection of species in danger of extinction; and the development of a system of protected waters throughout the nation (Moyle, 1995) are also good for the management of freshwater biodiversity. An increasing trend of using destructive fishing gears (as specified above) and the use of small-sized mesh gill nets destroy non-targeted aquatic organisms as well as small-sized fish-fry and fingerlings. Such practices may have unwanted impacts on the aquatic ecosystems and the aquatic biodiversity unless important fish habitats are protected by laws (Swar, 2002) prohibiting the use of destructive fishing methods.
An example of rainbow trout fish farming in Nepal
Rainbow trout (Oncorhynchus mykiss) were first introduced in the late 1960s from UK, Japan and India. The lack of technical know-how made it a failure at that time. They were reintroduced in 1988 after the development of cultural technology for this particular species by NARC. Successful breeding was performed in Nepal in 1990, which provided input for initiating experimental culture beginning in 1993.
Trout farming was mainly limited to the public farms on an experimental basis until 1998. At present, it has been extended to three private farmers who started trout culture on their own land, producing 4–5 tons of trout annually. More areas are being surveyed to find suitable sites for trout farming. Rainbow trout can be grown in the midhills of Nepal with the annual temperature range of 0–25°C, where their growth is very good in the temperature range of 10–20°C. Economic studies of the private trout farms have revealed very promising results for the expansion of the industry to other parts of the country. However, careful and intensive management is needed for boosting trout farming, because very good water quality and feeds are needed in addition to the initial high monetary cost. As international regulations applied to the aquaculture industry include fish welfare and safe food criteria, such regulations must also be included in a future Nepal fish farming industry. Researchers hope that it will turn out to be a success story in the near future due to the establishment of well-developed technical support, as well as growing demand for trout in the country (Nepal et al., 2002). However, there has been little work completed on the impact of trout farming on native fish species. Therefore, the researchers should begin their investigations on the ecological impacts of trout farming on other aquatic biota including native fishes.
Fisheries science and management
Different agencies working with the water bodies in the country are managing the resources independently of the scientists working with fisheries sector. In this regard, applicability of the research findings for the management of fisheries science has not been improved. Freshwater fish species of Nepal need further studies for proper classification. Public organizations, private institutions as well as the individual scholars can also help to solve this problem by engaging themselves and encouraging others in the field of fish science. Data sharing and collaboration among the academic institutions and public organizations could be a solution in bridging fish science and its management.
Priority gaps and needs
A recent survey (1992–2001) of scientific publications on freshwater ecology revealed that the representation of scientists from tropical Asia is extremely low (2% of more than 4500 papers). Even the protection of water resources for conservation of biodiversity in this area is very low, with weak legislation enforcement (Dudgeon, 2003). Similarly, insufficient research in the field of aquaculture is one of the drawbacks for the development of fisheries science in Nepal. Implementation of the research works and their dissemination is another problem common to tropical Asia, as indicated by Dudgeon (2003). A priority is also needed for fishery resource development in high dams and irrigation projects by maintaining their natural habitats (Shrestha, 2003). Threats to the freshwater fishes due to habitat destruction, mainly due to pollution, is one of the main priorities that must be included in future research.
There is a huge possibility of fisheries enhancement in the country given the abundance of water resources, rising demand of animal protein, income generation and recreation/sports fishing. The running waters of the country (more than 6000 rivers and streams) can produce a large amount of electricity, in addition to the aquaculture production.
There is need for a long-term program of basic, as well as applied, aquatic ecology, genetics and biotechnology (Shrestha, 2003), as well as ecotoxicological studies to assess and guide restoration of polluted production areas. The tools for the management of subsistence, commercial as well as recreation/sport fisheries in the country include regulatory laws, stockings, hatchery development and habitat improvements (Shrestha, 2002). Reduction of the substantial gap between knowledge and adoption of management and technological practices by concerned sector is also needed for the proper management of fisheries science in the country (Rauniyar, 1998). Communication and joint identification of priorities between the researchers and managers through regular workshops and national database (Minns, 2001) is an essential aspect for reducing the gaps in fisheries management. Use of new technologies such as radiotelemetry and GIS databases for the conservation of rare and endangered fish species has become essential for the proper management of freshwater fish species and their habitats. To conclude, a priority area in the field of freshwater fisheries must be developed by the scientists and managers so as to manage the diverse fish species and their habitats scientifically. For example, a long-term perspective in the field of aquatic ecology, genetics, biotechnology and ecotoxicology is essential to enhance the fish and fisheries science in the country.
Acknowledgements are due to Prof. Reidar Borgstrøm, and Prof. Bjørn Olav Rosseland, Norwegian University of Life Sciences, for giving constructive comments and suggestions to improve the quality of the manuscript even during their busy schedules. Prof. Jon Swenson deserves sincere thanks for correcting the language in its early stage. I would also like to thank two anonymous referees for their constructive comments and suggestions.