Electrofishing for fish larvae and 0+ juveniles: equipment modifications for increased efficiency with short fishes

Efficient use of electricity to collect fish larvae and 0+ juveniles can be achieved by reducing anode size relative to the cathode, demonstrated on two portable backpack-style electroshockers: the Martin Pecheur II and the Deka 3000. The effective field of galvanotaxis/narcosis of the anode was defined through technical tests, and the frequency distributions of samples from three floodplain ecosystems demonstrated a wide range of 0+ fishes collected: from 5 to 20mm for larvae, and from 9 to 200 mm for O+ juveniles. Advantages of collecting 0+ fishes with electrofishing by point samples are reviewed.