**The title, authors, and abstract for this completion report are provided below.  For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**

Sea lamprey population dynamics: updating demographic models and application to a novel control strategy

Michael L. Jones ¹, Gretchen J. A. Hansen¹, Weihai Liu¹, Brian Irwin¹, Andrew J. Treble^1,2, and Heather A. Dawson^2,3

 ¹ Quantitative Fisheries Center, 13 Natural Resources Bldg., Michigan State University, East Lansing, MI 48824-1222

²Current address: Department of Fisheries and Oceans, Sea Lamprey Control Centre, 1 Canal Drive, Sault Ste. Marie, ON P6A 6W4

 ³Current address: U.S. Fish and Wildlife Service, Marquette Biological Station, 3090 Wright Street, Marquette, MI 49855

Abstract

Integrated management of sea lampreys requires the use of population models to compare the outcomes of a variety of management strategies. The reliability of decisions made based on population models is directly related to the accuracy of the parameters describing population processes contained within them. In an attempt to update current sea lamprey population models, larval growth, recruitment, metamorphosis, and survival parameters were estimated using data from quantitative assessments carried out since 1995 as well as additional data collected to directly measure these demographic rates. Results suggest that sea lamprey growth is non-linear, contrary to previous assumptions used in population models of sea lamprey growth. High levels of density-independent variation in sea lamprey recruitment were observed, indicating that environmental factors may play a large role in determining year-class strength. Models of sea lamprey metamorphosis were developed with higher predictive power than existing models. It was not possible to estimate larval survival accurately using quantitative assessment data, and surveys specifically designed to measure larval survival should be used if an accurate measure is desired. An operating model of the entire sea lamprey management process was developed, which included updated estimates of larval demographic rates generated through this study. This model has been used to evaluate the outcome a variety of sea lamprey management decisions. A variation of this model has also been used to explore the potential consequences of genetic manipulation for sea lamprey control, and has demonstrated that skewed sea lamprey sex ratios could increase the potential effectiveness of a genetic manipulation of sex determination. Results also indicate that such a genetic manipulation could be maintained in the sea lamprey population indefinitely, increasing the risk of unintended and irreversible consequences. The operating model of sea lamprey management developed and refined through this study represents a powerful tool for examining the outcomes of management decisions, and refinements of larval demographics have greatly improved the predictive power of this model.