Laboratory Testing of a Modified Electroshocking System Designed for Deepwater Juvenile Lamprey Sampling

A submersible sled with the ability to electroshock and detect larval lampreys via an optical camera was developed to sample deepwater rearing habitats (>1 m). Three trials, each with 10 juvenile western brook lampreys Lampetra richardsoni (70-150 mm), were conducted in a laboratory setting to determine the effective shocking area and detection efficiency of the device. Electroshock was delivered for 30 s, and lamprey responses were observed. The detection efficiency ranged from 40% to 70% for the three trials (mean detection efficiency = 60%). Mean postshock emergence time was 4.4 s, and the maximum was 13 s. The device detected juvenile western brook lampreys without the need to transport them to the surface, thereby increasing sampling volume per unit time and reducing the potential for injury caused by handling. The system was developed to determine juvenile lamprey presence in regions where backpack electrofishers are unable to survey due to water depth.