IMPROVING ZOOPLANKTON SAMPLERS WITH SIMPLE ELECTRONICS

The addition of simple, inexpensive electronic circuitry to plankton nets and traps can significantly improve their performance. It is often difficult, particularly at great depth on windy days, to determine the exact depth at which the doors of a plankton trap close. The addition of a magnet to the trap door, and a magnetic switch to the trap housing allows delivery of a telemetered signal to the operator indicating that the trap doors have closed. Commercially available tow nets cannot detect changes in filtration efficiency during the course of a haul. A telemetered net is introduced that can detect such changes, allowing the operator to determine if efficiency changes due to clogging have occurred during the tow.