A trap for capturing planktonic chironomid larvae

This paper describes the construction and field operation of a trap designed to investigate the movements of larval Chironomidae in the open water of lakes. Although the trap was designed to be multidirectional, with six trapping bottles, only two directional components, vertical and horizontal, could be distinguished. This led to examination of three bottles only during later field studies, namely bottle 1 facing into the current, bottle 5 facing the substrate and bottle 6 facing the surface of the lake. Some results are presented and trap operation and sampling efficiency discussed. A major advantage of the trap is its use as a long term accumulator of planktonic organisms as opposed to traditional spot sampling techniques which tend to miss the less numerous plankters.