1. offshore safety zone: the area around an offshore installation within which vessels are prohibited from entering without permission; special regulations protect installations within a safety zone and vessels of all nationalities are required to respect the zone. (IHO Dictionary, S-32, 5th Edition, 4471)
  2. nature reserve: a tract of land managed so as to preserve it's flora, fauna, physical features, etc.
  3. bird sanctuary: a place where birds are bred and protected.
  4. game reserve: a place where wild animals or birds hunted for sport or food are kept undisturbed for private use.
  5. seal sanctuary: a place where seals are protected.
  6. degaussing range: an area, usually about two cables diameter, within which ships' magnetic fields may be measured; sensing instruments and cables are installed on the sea bed in the range and there are cables leading from the range to a control position ashore. (IHO Chart Specifications, S-4)
  7. military area: an area controlled by the military in which restrictions may apply. (Hydrographic Service, Royal Australian Navy)
  8. historic wreck area: an area around certain wrecks of historical importance to protect the wrecks from unauthorized interference by diving, salvage or deposition (including anchoring). (IHO Chart Specifications, S-4)
  9. navigational aid safety zone: an area around a navigational aid which vessels are prohibited from entering.
  10. minefield: an area laid and maintained with explosive mines for defence or practice purposes.
  11. swimming area: an area in which people may swim and therefore vessel movement may be restricted.
  12. waiting area: an area reserved for vessels waiting to enter a harbour.
  13. research area: an area where marine research takes place.
  14. dredging area: an area where dredging is taking place.
  15. fish sanctuary: a place where fish are protected.
  16. ecological reserve: a tract of land managed so as to preserve the relation of plants and living creatures to each other and to their surroundings.
  17. no wake area: an area in which a vessels' speed must be reduced in order to reduce the size of the wake it produces.
  18. swinging area: an area where vessels turn. (Service Hydrographique et Océanographique de la Marine, France)
  19. water skiing area: an area whitin which people may water ski and therefore vessel movement may be restricted.
  20. Environmentally Sensitive Sea Area (ESSA): a generic term which may be used to describe a wide range of areas, considered sensitive for a variety of environmental reasons. (IHO Chart Specifications, S-4)
  21. Particularly Sensitive Sea Area (PSSA): an area that needs special protection through action by IMO because of its significance for regional ecological, socio-economic or scientific reasons and because it may be vulnerable to damage by international shipping activities. (IHO Chart Specifications, S-4)