Physiological and behavioral responses of sea lamprey to low frequency sound
Sea lamprey control in the Great Lakes needs devices that selectively pass valued fishes, while blocking or guiding sea lamprey, to address stakeholder desire for increased aquatic connectivity. We conceptualize that sound may be an important component of selective fish passage devices because most fishes detect and respond to sound, but vary in frequencies of greatest sensitivity. Sound propagates through water regardless of water velocity, clarity, and lighting and has been used to reduce impingement of fishes or guide fish a variety of man-made structures. Preliminary work suggests sound could be a useful tool for sea lamprey control but no systematic studies have been done on sound detection ability in this basal vertebrate. We will address two research questions: (i) what sound frequencies do sea lamprey detect, and (ii) what is the behavioral response to detected frequencies. For both objectives we will test juvenile and adult sea lamprey to understand ontogenetic changes in responses, and also to identify potential control stages for downstream migrants and returning adults, the former representing a gap in current control efforts. If results are promising, we will later propose to test results in natural streams and responses of non-target species such as lake sturgeon, walleye, sucker, and salmonids.