Status of mahseer fishery resources: options for development and conservation

Mahseer is a common name given to a group of important cyprinid fishes which are naturally distributed in the highland areas of China, the Trans-Himalayan Region, and South and South East Asia. This group, with its center of diversity in the Indian Sub-Continent, contains 41 known species belonging to three genera: Naziritor (1 species), Neolissochilus (19 species), and Tor (21 species); only eight or nine species are commonly known as “mahseer”. Two species have been introduced in the highland areas of Papua New Guinea, however, the impacts of these introductions are poorly known. Although mahseer is a popular fish for recreational fisheries and an important food source locally, management of the fishery resource and domestication of wild stocks for aquaculture are not well developed and the basic information on status and production are also lacking. There is no official reporting to FAO on the fishery and aquaculture production of this group of fish. However, several country have on-going stocking, recreational fishing, and pilot culture programs in place. There are reports the certain population of mahseer have declined due to illegal fishing, habitat degradation, and introduction of alien species, but only t. yunnanensis is on IUCN red list as an endangered species. No members of this group are listed in the CITES appendices. Little information is available on the parasites, pathogens, and diseases of mahseer. Some domestications programs are being carried out on golden mahseer (T. putitora) in Nepal, Bangladesh, and India and few isolated attempts for three other species tor mahseer (T. tor), Deccan mahseer (T. khudree) and musallah mahseer (T. mussallah) in India, and T. tambroides and T. douronensis in Malaysia. Nutrition and feeding research shows that mahseer requires high protein diet (30-40% protein), and some species breed with and without hypophysation in captivity. Research on golden mahseer in Nepal, India, Bangladesh and Pakistan has generated limited information on broodstock rearing, seed production and nutritional requirement. There are some recent publications on research into T. tambroides and T. douronensis in Malaysia (Sarawak). However, in general, information on members of this group is sparse in the primary literature. Sustainable fishery and aquaculture development of mahseer includes management of wild stocks, protection of habitats, responsible hatchery production, development of domestication and breeding programs, safe trans-boundary movement based on risk assessment and implementation on conservation measures to protect or rebuild vulnerable and endangered stocks. Further, along with development of domestication programs and aquaculture technologies, region-specific habitat management measures deserve special attention to rebuild the stock of this group of species. Enhanced public awareness and people participation in conservation efforts and monitoring and surveillance of implementation of conservation plans will become essential in the future. The 2002 Kathmandu Symposium on Cold Water Fishes of the Trans Himalayan Region emphasised that effective collaboration and networking on a regional basis is imperative to address overall development and conservation of the mahseer fishery and aquaculture. The needs identified include; (a) more research, training and education into the Asia/Himalayan coldwater aquatic systems, (b) improved collection, access to, analysis and synthesis of existing information and experience, (c) better integration of fisheries development within overall ecosystem and rural development approach, (d) better understanding of socio-economic conditions and livelihoods of fisher communities and (e) transfer of experience of upland coldwater aquaculture development between mountainous regions of neighbouring countries. This paper will review and present the history, present status, challenges, opportunities and constrains for future development and conservation of mahseer fishery stocks.