Rainbow trout farming system in Nepal

Source: [FAO Corporate Document Repository] Fish production in Nepal is confined to inland waters including ponds, lakes, reservoirs and rivers. The southern Terai region of the country is the main area for warm water aquaculture. Aquaculture of common carp, Chinese carps and Indian major carps substantially increased from 1 150 tons to 15 023 tons from 1979 to 2000 (DOFD, 2001). However, cold water fish culture in the mid hills is at the very beginnings although a few ventures show that it is a profitable enterprise. Rainbow trout is the best suited exotic fish for growing commercially in mid-hills of Nepal. The culture technology and seed of rainbow trout are available in the country.

Rainbow trout (Oncorhynchus mykiss) was introduced to Nepal for the first time in the late 1960s and early 1970s from UK, Japan and India. It could not survive due to the lack of technical know-how and was re-introduced from Japan in 1988. During this period, the Nepal Agricultural Research Council developed the breeding and culture technology for this species. Rainbow trout is a carnivorous species which requires high protein feed and well oxygenated water. In nature it feeds on aquatic insects, small crustaceans and small fish. It can be cultured using artificial feed of no less than 20 to 30 percent of animal protein.

Rainbow trout is able to live within a temperature range of 0-25°C and it grows at the water temperature range of 10-20°C. The fish reaches commercial size (200-300 g) during the second year (Huet, 1975). In Trishuli, Nepal, it reaches 200-300 g within 14-months from the free-swimming larval stage (FRS, Trishuli), depending on the quality of the feed, adequate supply of water of suitable quality, including a suitable temperature and dissolved oxygen concentration.

Rainbow trout was bred for the first time in Nepal in 1990 and its culture was initiated experimentally in 1993. Present trout production is more than 10 metric tons annually from two government stations, and about 2-3 metric tons from the private sector. Mr. Purna Bahadur Lama from Kakani Village Development Committee-4 of Nuwakot District is the first private trout culturist in Nepal. He started rainbow trout culture in 1998 on a trial basis. Presently, he has been growing 10 000-12 000 fingerlings of rainbow trout each year in an area of 136 m2.

The main objective of this paper is to provide information on the economics of trout production in Nepal and it's potential for future expansion in the private sector.

Two Fisheries Research Stations, Godawari and Trishuli, under the Nepal Agricultural Research Council (NARC) are raising rainbow trout from eggs to adults and vice versa. Both stations are culturing the fish in concrete raceway ponds. As a source of water, spring water at Godawari and river (glacier and snow melt) water at Trishuli are used. The total area of ponds for trout culture at Godawari is nearly 300 m2. Trishuli station has about 2 000 m2 surface water area for trout farming of which about 1200 m2 has been used for grow-out fish and the rest for broodstock of trout as well as for native fish species.

Presently, three private farmers including Mr. Lama from Nuwakot district and one farmer from Parbat culture trout. This is a positive sign in the development of trout aquaculture entrepreneurship. They can produce 4-5 tons of trout annually under present conditions. Some new areas are being surveyed to find out suitable sites for trout aquaculture. Water of the Modi Khola (Parbat), Khimti (Dolakha), Khokundol (Sindhupalchowk), Naubise (Dhading) have been found suitable, but sites for raceway construction still need to be identified.