Many definitions of the term Marine Protected Area (MPA) exist, most of which connote different levels of protection for the marine environment. Probably the most widely accepted definition is the one developed by the International Union for the Conservation of Nature (IUCN). It states that MPAs are "any area of intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, which has been reserved by law or other effective means to protect part of all of the enclosed environment." Levels of protection can vary from site to site as can reasons for protection. Examples include: 1) areas closed to fishing for one or more species, or 2) areas closed to all human activity, including non-consumptive use.