For fish culture and the fisheries in Lake Phewa, Begnas and Rupa, it is important that the water quality does not deteriorate. Two potential reasons exist for changes in water quality: (a) siltation filling up the lakes, and (b) organic pollution from fish feed. Further, the lake level changes at Lake Phewa due to the dam could influence the water quality. Therefore it is recommended to monitor the water quality in Lake Phewa, Begnas and Rupa. Monthly measurements at one point in each lake of temperature, dissolved oxygen and transparency could be sufficient. By taking two dissolved oxygen profiles with about three hour intervals, an estimate of the primary production can also be obtained. (This exercise is of particular interest when cage culture expands.
The natural fishery will be influenced by changes in water quality, by regulations on fishing and by stocking of the lakes. To evaluate these effects it is recommended to monitor the catch results of the Podhe fishermen. A monthly round of interviews as done in 1977 would be enough. Changes in total catch, as well as per lake, per gear type, and per species can be followed.
In relation to this it is also recommended to survey the types and numbers of fishing gear owned by the fishermen. This could be done every 12 or 18 months to assess changes in the gear used (quantity, mesh size). The first survey of early 1977 can be used as a comparison.
A tool for monitoring the actual fish population itself would be useful. Therefore it is recommended to fish at monthly intervals with a multipanel gillnet in Lake Phewa, Begnas and Rupa. This could be supplemented or replaced by electro-fishing if equipment becomes available.
As the present licensing system does not cover all gear of the private fishermen, a change seems useful. It is recommended to have licences covering all gear of one fisherman, e.g., (a) a big licence allowing for up to 600 m2 of gillnets, plus two castnets, plus several hooks; (b) a small licence allowing for two castnets; (c) a small licence allowing for several hooks. For control purposes, it could be easier to allow for 11 gillnets on a big licence, although an area measurement seems more fair.
From catch records as well as fishery biology studies, it seems that the potential of the lakes for a natural fishery is fairly well exploited. In the first instance, it is doubtful if stocking will contribute to a higher fish production. Thus, it is recommended not to start any large-scale fish stocking. It would be most economical to evaluate first the effect of the release of 10 000 (or less) good sized carp fingerlings. On the basis of the returns of this, further decisions can be taken.
The Fishery Section's catches have declined. Probably the Section competes partly with the fishermen for a small amount of fish. Thus, it is recommended to stop fishing operations by the Fishery Section (except data collection as indicated above).
The Pokhara Valley lakes have a multi-species fishery. This makes any regulations tailored to one species difficult. They will not allow for optimum exploitation of another species. Thus it can be recommended: (a) to allow only gillnet meshes of 30 mm and above (this would basically be as at present); (b) to allow only gillnet meshes of 125 mm and above, This would be tailored to a better management of the sahar stock. However, it would in first instance, decrease the overall catches and would probably not result in an overall increase in the long run.
The choice between 8(a) and 8(b) is a matter of socioeconomic considerations.
As the breeding seasons of the fish are very spread out, regulations to protect breeding fish do not seem feasible.
The indigenous fish species do not seem under any threat of extinction by exploitation, although some stocks might be diminished, therefore, it could be useful to declare either or all of the small lakes (Maidi, Kaste, Deepang) a sanctuary for fish. This might be combined with a bird sanctuary.
Lake Maidi, Kaste and Deepang are likely to disappear quite fast through peat formation by aquatic plants. It is recommended to start some dredging operation to counteract this if it is desired to keep some water in these lakes.
As the riverine fishery is difficult to assess and to manage and as its potential is probably quite small, it is recommended to not spend time on the riverine fishery but rather to concentrate on fish culture in lakes and ponds as more promising areas of activity.
Referring to para. 3.4 above it is recommended:
to allow local people to fish in Lake Rara freely until such time as they are removed from the national park;
not to introduce any exotic fish species into Lake Rara.
Referring to para. 3.5 above, it is recommended:
to start a detailed study on the fishery possibilities of the Karnali River Reservoir as soon as this project is approved;
to assess fishery potential of any new hydro-electric projects.
