Electric field-induced detachment and vibration analysis for Sea Lamprey
Objective: Sea lamprey Petromyzon marinus , a known ecological threat to native fish populations in the Great Lakes, use their oral suction disc to navigate challenging environments when moving upstream to spawn. This study investigated the physiological response of adult sea lamprey to detach under pulsed direct current electric fields. Methods: Adult sea lampreys in an attaching position were exposed to pulsed direct current electric fields at four different field strengths (0.7, 1.1, 1.3, and 1.9 V/cm). Behavioral responses, including detachment and vibration, were observed and analyzed. Fast Fourier Transform analysis was applied to vibration data to quantify the frequency of vibration exhibited by non-detached sea lamprey. Statistical correlations between detachment rates and vibration responses to sea lamprey sex, weight, and length were evaluated to determine influencing factors. Results: The highest detachment rate (91%) was observed at 1.1 V/cm, with the detachment rate above 70% for other field strengths. Fast Fourier Transform analysis revealed that the vibration frequencies closely matched the signal while stronger fields elicited a more pronounced vibration amplitude without significantly increasing detachment. Non-detached sea lampreys exhibited “twitching” behavior synchronized with the electric field frequency. Sex, weight, and length had minimal influence on detachment rates and vibration responses. Conclusion: This study provided insights into the behavioral responses of sea lamprey under electric fields, highlighting the potential for optimizing electric deterrents for selective control. While not all sea lampreys detach during electroshocking, understanding their behavior can be crucial in maximizing detachment rates and contributing to improved management strategies for this invasive species.