USE OF ELECTRICAL-STIMULATION IN THE AUTOMATIC SEPARATION OF SOFT-SHELL CRAWFISH

Red swamp crawfish (Procambarus clarkii) were evaluated for their elec trical resistance, recovery time, and response to DC and AC fields. In a DC field, crawfish were forced to move toward the anode. Crawfish i nitially facing the cathode displayed forced backward walking, rapid b ackward escape by tail-flipping actions. and immobilization as the app lied voltage was increased. Crawfish facing the anode exhibited forced forward walking and immobilization as voltage increased. Crawfish pla ced in an AC field displayed actions similar to those observed for the crawfish initially facing the cathode in the DC field. The use of beh avioral response in an electric field to inhibit crawfish movement was evaluated with an electrical inhibition gate. The inhibition gate red uced the number of crawfish that escaped from a culture tray by approx imately 80%. Increasing voltage or extending the duration of electrica l stimulation prolonged the recovery period. The results indicated tha t an electrical inhibition gate can be successfully used for soft-shel l crawfish separation. The proper voltage is lower than 20 V for DC an d lower than 12 V for AC.