Coastalshed: A term to facilitate improved management in a large diverse area of the earth's surface

•We critically review terms referring to where water and land meet and interact.•We conclude that the existing terms are an impediment to successful management.•We propose the term “coastalshed” to clarify the geographic area for management.•Coastalshed area includes a nation's coastal subwatersheds, estuaries and the EEZ.•The coastalshed area is that area that logically requires management.•A test case for Canada is presented to examine the coastalshed concept.

Since the publication of the World Commission on Environment and Development (WCED) Report in 1987, managers, scientists and citizens have struggled to effectively describe and communicate the geographic area of interest with regards to integrated coastal and ocean management (ICOM). In the WCED report, under the section “Oceans: the balance of life”, it is stated: “Five zones bear on this management: inland areas, which affect the oceans mostly via rivers; coastal lands – swamps, marshes, and so on – close to the sea, where human activities can directly affect the adjacent waters; coastal waters – estuaries, lagoons, and shallow waters generally – where the effects of land-based activities are dominant; offshore waters, out roughly to the edge of the continental shelf; and the high seas, largely beyond the 200-mile exclusive economic zones (EEZs) of coastal states' control.” The authors focus on the first four of the five zones as these fall within national jurisdictions and have been the focus of ICOM for decades.It has been a struggle to develop commonly accepted terms that refer collectively to these four zones. Phrases such as “coastal and ocean”, “coastal zone”, etc., have been used. None of these terms, however, adequately capture the linkages among the land, freshwater, estuarine and marine ecosystems – the geographic extent and purview of ICOM. The word “coastal” has the connotation of being associated with “salty” water. It doesn't adequately take into account land-based activities such as farming, forestry, hydro-power generation, etc. which have an impact on, and are affected by, the coastal and marine environment.To address this challenge, the authors propose a new term, “coastalshed”, to recognize and communicate the area of the globe that is comprised of the ocean area under the jurisdiction of a national government, the adjacent coastal and estuarine area, as well as the land and freshwater in the subwatersheds feeding into this marine area. Essentially we wish to extend the concept of “watershed”, as a drainage basin, from the freshwater, downstream through the estuaries and out into the open ocean. The purpose is to clearly delineate a geographic area that would be subject to integrated and collaborative management, namely ICOM.The coastalshed concept is applied to Canada as a means of introducing the term and concept for management purposes.