Monitoring the aquatic fauna in the western extension area

loc/Ycu ftryBTol85.8 MONITORING THE AQUATIC FAUNA IN THE I^]ESTERN EXTENSION AREA The team in charge of aquatic monitoring in the Western Extension area became truly operational only at the beginning of October 1984 so far as routine monitoring is concerned. Consequently, the report presented covers only the last three months of 1984. It is thus evident that none of the results presented can be interpreted as yet because of the sti1l too scattered nature of the sampling, particularly since most of the work done consistedin numerous reconnaissance missions with a view to choosing the most repre- sentative sites in the upper basins of the Niger and the Senegal. During these 3 months, in entomology as well as in ichthyology, 26 stations were investigated once or several times. Among them, a certain number seem tobe representative and could be chosen as sites for posslble regular visits. A provisional list is given in this report. A definitive list, however, eould not reasonably be drawn up until an annual cycle of visitg especially duringthe rainy season has been completed,particularly with a view to making surethat the sites are accessible at all seasons. In the zone under consideration the work is to be done in two types of environment that are somewhat differentfrom each other. In Mali the headwaters of the Senegal are typical savanna rivers that flow for just a short time. For example, this yeai flow stoppedin some rivers from December 1984 onwards. However, it would seem that in a normal year flow is spread over a longer period. The 1984 high-water 1eve1s were the lowest since 1903, reaching onty 1/l of mean high-r^rater 1eveI in theNiger and 1/5 in the Senegal. outside Ma1i, on the other hand, studies areto be done on the headwaters of the Niger in the Kankan region in Guinea.There, it seems that most of the watercourses are permanent. The team is also responsible for the training of future members of the national teams. At the present time, 4 people, two Guineans and two Malians, are being given a training courses that began in November 1984 and will continue to the end of 1985. In Apri1, 4 others will join them for six months. 0n the whole, the monitoring protocol the same as the one at Dresent in force.laid on entomology, sttrdy of the colonisat tlre use of nets of larger mesh at cer[ain team is coltecting data on the biology of to be applied in this zone will be llowever, particular stress will beion of artificial sub-strata, and stations. As regards fishes, the the main species.