Defining sediment handling practices to limit negative impacts to larval lampreys

Sediment manipulation activities such as dredging and restoration efforts (e.g., culvert install/repair) may disturb habitats where larval lampreys live burrowed in stream sediments. Sediment added on top of larval lamprey burrowing areas results in ‘overburden’, which poses risks of mortality from respiratory distress, reduced movement, and crushing injuries or may have sublethal effects such as changes in growth or burrowing activity. To avoid negative outcomes, larvae must be able to vertically migrate through the overburden to reach areas near the new (elevated) sediment-water interface. Current guidance on how to limit negative impacts to lampreys during sediment handling activities is limited by a lack of information on how lampreys respond to overburden. The goal of this study was to evaluate larval lamprey responses to variable overburden depths and exposure durations using two sediment types: fine (