Current invasive species research being conducted at MSU
Return to MSU Research

Project 2

Project Title: Defining targets for sea lamprey control in the Great Lakes: economic injury levels and fish community goal-based targets.
Investigators: James R. Bence and Michael L. Jones
Contact: James R. Bence (bence@msu.edu)

Abstract:  Economic injury levels (EILs) are defined as sea lamprey control levels above which incremental increases in expenditures on control do not pay for themselves in terms of fishery benefits (increased harvest). These EILs are based on the relationship between equilibrium sea lamprey abundance and expenditures on controls combined with estimates of damages (value of fish killed) caused per sea lamprey. The objectives of this project are: 1. To develop EIL estimates for all five Great Lakes using common methods and assumptions. 2. To review the assumptions, strengths, and limitations of alternative methods for determining appropriate targets for sea lamprey control in the Great Lakes. 3. To evaluate how sea lamprey abundances corresponding to the preliminary damage target of five A1-3 marks per 100 lake trout proposed by the Sea Lamprey Integration Committee compare with EIL sea lamprey abundances. The importance and urgency of this project is reflected by the fact that our proposal responded to a call from the GLFC Commissioners to provide EILs and/or other targets for sea lamprey control in each of the Great Lakes by June 2007. To apply the EIL approach we will use an existing age-structured stochastic simulation model for the entire sea lamprey life cycle to establish how sea lamprey equilibrium abundance varies in response to control budgets for each of the Great Lakes. We will use existing information from a sea lamprey feeding model along with information on the value associated with harvested fish to determine where the EIL falls along the sea lamprey abundance versus control budget curve for each lake. To apply this EIL approach and achieve the other objectives of this project the following tasks will need to be completed: (1) assemble databases necessary to simulate sea lamprey control on each of the five Great Lakes; (2) calibrate the simulation model for each lake using recent control expenditure and lamprey population assessment information; (3) lead a workshop with sea lamprey program biologists to present our models for discussion and refinement based on their experience with sea lamprey populations and control; (4) calculate EILs for each of the Great Lakes; (5) describe the existing damage target method, rationale for its use, and its relationship to EILs; and, (6) summarize the strengths and limitations of these and any other methods proposed during this study.