EVALUATION OF THE EVERY DREDGE FOR DETERMINING UMBERS OF SNAILS IN TROPICAL RESERVOIRS

摘要

Since control of the acuities snails which transmit schistosomes can be very expensive in large hydroelectric and irrigation reservoirs, it is important to understand precisely the dynamics of these snail populations in order to plan efficient programs for their control. Thus sampling methods are needed to measure the numbers of snails in the reservoirs and this report concerns the use and evaluation of the Emery dredge in nine reservoirs in Puerto Rico. The results showed that the hosiery dredge could be utilized under certain conditions to accurately estimate numbers of snails in these reservoirs.