3. DISCUSSION AND RECOMMENDATIONS

The present status and the necessary improvements for the two existing hatchery-nursery units are basically similar.

3.1.1 Present methods

A pond based spawning system is operated, using kakabans and hapas. The fertilized eggs are regularly collected and placed in other tanks for hatching and rearing. In the past year, manuring of pond water has been introduced to increase natural production in the ponds. Current methods of breeding technology have considerable limitations in efficiency and productivity. New techniques are therefore justified.

3.1.2 Hatching tanks/ponds

These are about the only facilities provided in the units. They are small in size and are inadequately designed. They are fully brick-lined, thus inhibiting natural food production.

Drainage is from the bottom through a plugged pipe; water level control is therefore practically impossible. Small diameter pipes are used to collect drained water. These are usually choked up. Regular cleaning is labour demanding and difficult.

3.1.3 Water supply

The water supply of the Tarbela unit depends on residential tube wells; supply from which has second priority. Reliable and independent water supply should be established.

3.1.4 Recommendations

While the production potential of the existing hatcheries is not negligible and may be usefully increased by following the recommendations provided in the consultant's first request, the capacity will not be sufficient for the project's overall. These hatcheries together with the newly proposed units can however provide good facilities for different breeding techniques under a well trained farm management.

3.2 The newly proposed hatcheries

In the new units, modern production methods will be introduced to provide better productivity and overall security of operation.

Detailed technical reports are given in the attached annexes: a short summary is provided here.

3.2.1 Technology and production target

The proposed technology is basically that of hormone induced ovulation, artificial egg fertilization and hatching and rearing in funnel type jars.

To increase the security of production, the units would provide facilities for the Chinese system of spawning, hatching and rearing in circular tanks.

In addition, the existing ponds provide further capacity for spawning.

The brood fish are either grown on farm or collected from the reservoir. In the absence of exact data, the fish seed requirements have been estimated by comparing conditions with those of other reservoirs in the region. The following data are considered to be reasonable targets. Thus, the expected (fingerling) production of common carp, Chinese carps and Indian major carps species is:

3.2.2 Ponds

The ponds are earthern with a natural soil base. Their sizes are defined according to the operating requirements.

Each pond can be changed and drained separately. Drainage is through monks or similar structures into a drainage canal. This ensures the control of water level and the automatic release of excess water.

The maintenance of drainage canals is easier and can be more easily kept clean than can drainage pipes, although the latter occupies less site area.

Summary of pond characteristics:

3.2.3 Water supply

The water for the pond components is supplied from irrigation canals (Hub and Mangla) or from tube wells (Tarbela). On each site pumping is necessary to convey the water to the site.

In the case of the Hub supply, permission for using the irrigation canal water must be arranged with the authority involved.

Summary of water supply:

3.2.3 Hatchery system

The hatchery system comprises the facilities for brood fish handling and treatment, and for hatching of eggs and rearing of larvae.

Its production potential is higher than that required for the present, but this allows for future needs, and provides for generous operational capacity.

The water supply is pumped from tube wells with a capacity of 9 l/s. Operational security is ensured by the use of a number of devices, including an emergency reservoir and a standby generator.

3.2.4 Cost estimates

Detailed cost estimates are presented in Annex 3. These are summarised here:

Note: The pond component of the Mangla station is already being implemented. Detailed cost estimates are being prepared by WAPDA staff.