Ethnobotanical Leaflets 10: 342-349. 2006.
Piscicidal Plants of Nepal: Checklist, Ethnobotanical Uses and Indigenous Practices
Ananda R. Joshi* and Kunjani Joshi**
*Former Director General, SACEP, Colombo, Sri Lanka
**Harvard University Herbaria, USA
Email: [email protected], [email protected]
Issued 22 December 2006
Fish catching with the aid of plants and their parts is an ancient practice. The rural communities of Nepal collect piscicidal plants and their parts from various habitats, such as forest, scrub, grassland, cultivated fields, wetlands and riverbanks and use them following traditional methods and practices to stupefy fish. However, at present, the piscicidal plants and their ethenobotanical information are being eroded as a result of haphazard exploitation of resources, habitat destruction and land use change (Joshi and Joshi, 2005). The loss of traditional knowledge within cultures undergoing rapid change is just as irreversiable as the loss of species (Joshi and Joshi, 2004). Hence, priority should be given to document the useful plants and their uses along with indigenous knowledge, methods and practices. Though some ethnobotanical initiatives related to the piscicidal plants have already taken (Bhandary and Shrestha, 1982; Joshi and Joshi, 2005a; Karki and Rai, 1982; Regmi and Karna, 1989; Manandhar, 1989), less priority has been given to the systematic and comprehensive enumeration of these species and their conservation in an integrated manner. Therefore, an attempt has been made to document and enumerate the piscicidal plants with exising traditional uses and practices.
Study Areas and Methods
The ethnobotanical information were collected from the villages of the various districts of Nepal. The complex geomorphology, climatic variations and other physical characteristics make these villages rich in diverse habitats with useful species including the piscicidal plants. These areas are inhabited by different ethnic tribes, who have rich knowledge on ethnobotanical information. Ethnobotanical information was collected using various techniques and also verified with secondary sources.
Enumeration of Species
The plant species, which are reported to have piscicidal effects, are enumerated in Table 1. Seventy-nine piscicidal plants belonging to 35 families are arranged alphabetically by genus–species, family followed by local names, and parts of the plant used. Among the documented species, the family Fabaceae was most frequently represented with a total of 11 species, followed by Polygonaceae 7, Euphorbiaceae 6, Ateraceae 5 and others with less than 5 species.
Indigenous Knowledge and Practices
The local people have excellent knowledge of species identification, usefulness of the plants and traditional practices. Though the main occupation of villagers of the study areas is agriculture, fishing is an alternative source of income. They collect fish for food and also for sale in nearby markets. Maghi tribes are mainly involved in fishing occupation and used to utilize all parts or a certain part of the plant as fish poison. Sometimes for catching fish from rivers, the flow of water is checked either by erecting a temporary wall of mud and stones or by diverting the water current into small temporary ponds. The plant or a plant part is crushed and thrown into the water. The fish poison makes the fish float in a stupefied state and come to the surface of water from where they are easily captured.
According to the information of the local people, some species are preferred for fish poison and frequently used. These species are Agave cantala, Buddleja asiatica, Buddleja paniculata, Engelhardia spicata, Euphorbia royleana, Juglans regia, Persicaria hydropiper, and Sapium insigne.
Table 1. Piscicidal plants of Nepal.
Strategies for Sustainable Management
The following strategies are recommended for sustainable management of useful plant diversity.
<![if !supportLists]>1. Inventory, Chemical Screening and Documentation of the Species
Many parts of the biogeographical areas of the country have still remained unexplored. Hence, it is strongly recommended that major thrust should be given to an intensive inventory and documentation of piscicidal plants and their products. Emphasis should also be given to analyse chemical components of the plants and the parts which are used to stupefy fishes. A more systematic investigation of some of these plants may lead to the discovery of new economically useful products.
2. Documentation of Traditional information, methods and practices
The rural people have developed unique indigenous knowledge related to the uses of plant resources due to constant association with the forests. These existing valuable information are needed to be documented before lost or disappeared. As there is lake of the documentation system, priority should be given to develop a system for the systematic recording of the information related to the ethnobotanical uses and indigenous knowledge of the species.
3. Conservation of useful species and their habitats
Though forests, scrubs, grasslands and waste lands are the major habitats of the pecicidal plants, most of them appear to be restricted only to shaded forest habitats. An obvious conclusion that can be drawn from this picture is that deforestation and habitat destruction due to land use change would pose a serious threat to the species. Even without tree-removal, extensive grazing of domestic animals in the forests can be damaging to some species. When questioned about the changing status of the existing plants, our respondents listed some important species such as Coriaria nepalensis, Sapium insigne and Zanthoxylum armatum which have also declined in abundance during the last decade. The trend of decline of abundance of the useful species shows that action for conservation is urgently needed. Hence, efforts should be directed to formulate and implement appropriate strategies and programs related to the conservation and sustainable uses of these plants and their products taking consideration of the needs of the people.
The authors are thankful to the inhabitants of the study areas for their kind cooperation and help during the field survey. Thanks are due to Dr. John F. Edington, University of Wales, U.K. for his guidance and encouragement, and to Dr. S. K. Jain, Founder and Ex-Director, Institute of Ethnobiology, Lucknow, India for encouragement.
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