The Massachusetts Supreme Judicial Court (SJC) ruled on February 18 that the Massachusetts Division of Fisheries and Wildlife's (DFW) longstanding regulations for mapping and regulating development within DFW designated "Priority Habitat" of state listed species are a reasonable implementation of the Massachusetts Endangered Species Act (MESA) and within their authority under the statute. The SJC's decision in Pepin v. DFW upheld an earlier Superior Court ruling that MESA authorized DFW to review projects in Priority Habitat and to limit or require mitigation for impacts that may threaten species' survival by causing what is known as a "take" under the statute. The SJC opinion is a strong affirmation of the authority exercised by DFW in implementing MESA.

In the lawsuit that resulted in the SJC decision, William and Marlene Pepin challenged DFW's 2006 delineation of their property in Hampden as Priority Habitat for the Eastern Box Turtle and also sought an order striking down all of DFW's Priority Habitat regulations as beyond DFW's authority under MESA. In April 2010 the Superior Court ruled for DFW. The Pepins appealed these Superior Court rulings to the Appeals Court, and the SJC, on its own initiative, took the case from the Appeals Court. The SJC strongly affirms the previous Superior Court decisions in DFW's favor.

In evaluating the Pepins' arguments, the SJC noted at the outset that duly promulgated agency regulations are presumptively valid and must be accorded all the deference due a statute. Quoting from its recent decision in the Entergy case, the SJC stated that "a regulation?need not necessarily find support in a particular section of [the enabling statute]; it is enough if it carries out the scheme or design of the chapter and is thus consistent with it."

The SJC noted that the purpose of MESA, which includes preventing illegal take of state-listed species, is unambiguous. DFW's broad authority under the MESA statute extends to its use of the Priority Habitat regulatory approach, which "equips [DFW] with the capacity to preempt otherwise irreparable harm to habitats, a central objective of MESA embodied in the take prohibition." Consistent with DFW's own views, SJC characterizes the Priority Habitat regulatory approach as "ultimately a flexible one that gives guidance to landowners on structuring their projects to avoid committing takes, and, in doing so, ensures them a safe harbor from liability under the statute." In short, the SJC found that DFW's Priority Habitat regulations "serve to implement the existing statutory provision prohibiting takes of State-listed species, which is critical to the operation of MESA as a whole" and are "designed to facilitate property development, albeit in an environmentally sensitive manner."

The SJC decision leaves completely intact the DFW regulatory framework that has been developed by working closely with both the development and environmental communities for over a decade. The case drew broad national interest with briefs being filed supporting the DFW by Defenders of Wildlife, The Nature Conservancy, National Wildlife Federation, Massachusetts Audubon Society and others. The National Association of Home Builders and the Pacific Legal Foundation and others filed briefs to support the Pepins.