Management inferences from a demographic analysis of sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes

Abstract

We use matrix models incorporating uncertainty in values of life history traits and density-dependent survival to assess pest management strategies implemented by the Great Lakes Fishery Commission to control nonnative sea lamprey (Petromyzon marinus) in the Laurentian Great Lakes. The primary method of sea lamprey control has been treatment of rearing tributaries with chemical lampricides, but release of sterilized males and deployment of migratory barriers and traps are important components of the management plan. Uncertainties in the effectiveness of alternative control remain, however. Our models demonstrated that the management target of reducing lampricide use by 20% while maintaining current levels of control could be achieved if alternative methods are used to suppress current lake-wide fecundity rates by 49%–65%, assuming equal lampricide efficiency on larvae and metamorphosing individuals, or by 42%–55% when lampricide mortality on larvae is assumed to be half of that on metamorphosing individuals. At current levels of lampricide use, reduction to 72%–88% of current fecundity rates is recommended to ensure long-term control of sea lamprey populations in the face of uncertainty in current estimates of population growth rates. New control options targeting additional vital rates, such as survival of the parasitic life stage, could further reduce reliance on lampricides while maintaining effective sea lamprey control.