The goal of habitat classification is to provide a language through which data and information regarding habitats can be communicated and managed. This report provides background information on marine habitat classification, as well as information on current research efforts. By doing so, we hope it will facilitate a discussion on marine habitat classification in the Gulf of Maine region in which all stakeholders are able to participate.

Classification frameworks can be simple or complex, depending on the nature of the questions being asked. In general, a classification scheme covers a broad range of information and should be flexible and adaptable enough to evolve along with improvements in the science and understanding of habitats. Furthermore, a shift to ecosystem-based management requires a greater understanding of how habitats relate to each other and the environment around them. Classification schemes are important tools for studying these relationships.

There are a number of considerations and issues with classifying marine habitats in the Gulf of Maine region:

• The nature of the scheme chosen—whether developing a standard scheme for the region or selecting schemes on a case-by-case basis—can impact future conservation and management efforts.
• Habitat classification is scale dependent. Because of this, an appropriate scale should be selected, before starting the classification process, that addresses the relevant research or management questions. In the absence of a single appropriate scale, however, the scheme should be adaptable to various scales as needed.
• There is a shared responsibility between researchers and managers when it comes to communicating findings and research needs. This communication is important to ensure that a classification scheme meets both sets of needs.
• Classification and mapping efforts have the potential to greatly improve management decisions. These efforts can provide a better understanding of the cumulative effects and ecosystem impacts of seemingly isolated actions. But to increase the usefulness of such efforts, managers and researchers should communicate regarding what information is required to make effective management decisions.
• At their most basic level, classification schemes are rooted in either the physical or biological characteristics of the environment. Deciding on which type of approach to pursue will greatly affect the resulting structure and function of the classification scheme.

To help ensure that classification schemes can fulfill their potential, this report presents background information, methods, and current research—a primer of sorts—to serve as a foundation for an open, multi-stakeholder dialogue. Finally, some of the issues that could be addressed in such a dialogue are summarized as a starting point to the conversation.