Economics Analysis and Research Branch. The National Survey on Recreation and the Environment provided the base data for EPA s model of participation, though only ocean-related activities were covered in its report. The 2000 U.S. Census will include an improved recreation survey. It is impossible to make direct comparisons between states or to assess trends over time based on this closure data. Standards, monitoring, and closure practices vary from state to state, making it difficult to know, for example, whether a state with many closings has vigilant health officials or more coastal pollution.
Classification is based on surveys of water quality and pollution sources.
Individual growing areas are classified either as approved for harvest or as one of several restricted categories. All harvest must be prohibited unless sanitary surveys indicate that water quality meets specific NSSP standards for the other categories. Harvesting is permissible in approved areas year-round. Some potentially productive growing areas remain prohibited for harvest because of inadequate state resources to conduct the requisite sanitary surveys. The primary basis for harvest restrictions is the concentration of fecal coliform bacteria associated with human sewage and with organic wastes from livestock and wildlife.