A METHOD FOR IMMOBILIZING OR KILLING SWIMMING LARVAE IN A MASS OF FRESH WATER, AND AN ELECTRIC TRAP FOR PRACTISING SUCH A METHOD

摘要

A trap for swimming larvae in fresh water is constituted by two capacitor plates for influencing a mass of fresh water between the plates. An alternating current flowing in the interior of the larvae is able to kill the larvae, and the power dissipation of the trap is limited substantially thereto, while the effect of heating up the mass of water is avoided, since fresh water is a poor conductor. Therefore, it is sufficient with a voltage generator which supplies a relatively low power, i.e. a relatively high voltage but a limited current. In a method where the trap is used, a concentrated electric power dissipation of an immobilizing or killing magnitude is caused in the interior of the larvae. The interior of the larvae is constituted substantially of an electrically highly conductive liquid, and when an alternating electric field is established in the water between the capacitor plates, there will be an alternating polarization of both water mass and larvae, and an alternating current is caused inside the larvae.