"Some Members of Congress (among many others) are interested in considering limiting human activity in some areas of the marine environment as one response to mounting evidence of deteriorating conditions and declining populations of living resources. The purposes of proposed additional limits would be to both stem the decline and permit the rehabilitation of these environments and populations. One method of implementing this concept is to designate areas where activity would be limited, often referred to as marine protected areas (MPAs). Translating the MPA approach into a national program, however, requires resolution of many economic, ecological, and social debates. The complexity of creating a program is compounded by controversy over the uses that would be allowed, curtailed, or prohibited in MPAs; the purposes of a system of MPAs; and the location, size, and distribution of MPA units. One possible way to get past some of these complexities is to think of MPA designations as a form of zoning in the ocean. Experiences in using the MPA designation in other countries may be instructive. However, questions have been raised about the effectiveness of administration and enforcement and about changes in living resources at some of these sites."
CRS Report for Congress, RL32154
National Agricultural Law Center http://www.nationalaglawcenter.org/crs/