10. RECOMMENDATIONS

From the present report it may be deducted that only in a few cases adequate data series exist to produce annual yield figures or potential yield estimates. It was observed that if data collection took place, this was only for a limited period. Various types of data are crucial for stock assessment purposes as well as for fisheries management purposes. Therefore the following recommendations are presented. It should be noted that ambitious recommendations have been omitted and that only realistic ones are considered here:

• annual frame surveys be conducted (if this cannot be realized every year then at least every second year);
• a minimum of hydrological and limnological parameters be monitored, such as oxygen contents, temperature, pH and conductivity; as should the water level of the lake, depth and retention time;
• surveys be undertaken to confirm occurrence of small pelagics (in case of their absence introduction from nearby lakes or reservoirs may be considered);
• existing and developing small pelagic fisheries be monitored and their potential estimated;
• minimum statistical monitoring be organized;
• species and size composition data be collected for various mesh sizes used in the fishery;
• studies be carried out to determine changes in species composition over time;
• with the available information a model be determined with respect to water level control and optimal use of both the reservoir and the area downstream.

In order to decide on the minimum requirements for data collection it is recommended a workshop be organized to bring together those persons who are involved with the lakes in the study area. It is recommended that all literature as mentioned in the present report as well as in the Source Books (Vanden Bossche and Bernacsek 1990a, 1990b and 1991) be brought together in order to study existing data. All working group participants should present descriptions of their studies. Comparisons should be made and relationships established between various limnological, hydrological or morphometric parameters and fish yields.