Just over a decade ago, the zebra mussel came to the Great Lakes. This rapidly expanding species brought new attention to an issue of great importance to the Great Lakes, Aquatic Nuisance Species (ANS). The term Aquatic Nuisance Species refers to aquatic organisms not indigenous to a particular ecosystem, in this case the Great Lakes, which impose costs on the ecosystem and society. The devastating ecological consequences and the considerable direct economic costs of certain introductions, and the potential for future invaders, give the ANS issue importance and argue for efforts to prevent future threats. This paper provides an introduction to the economics of the ANS issue for the purpose of policy evaluation. The analysis in this paper utilizes a framework for policy evaluation that focuses on two facets of good policy design: the basis, the measure to which the policy is applied, and the instrument, which is the policy tool used. An effective policy will use an appropriate basis and instrument. This paper contains an review of a variety of different policy bases and instrument and explore their strengths and weakness with regard to economic theory and the unique nature of ANS invasions as well as which bases might be appropriate for which instruments.