Crustaceans continue to be the most important species landed in 2012 in terms of value, followed by shellfish and molluscs and tuna. ( The number of people employed in the fisheries sector decreased 19% between 2011-12 and 2012-13. ( The Offshore Constitutional Settlement 1983 (OCS) is the jurisdictional arrangement between the Commonwealth and states/Northem Territory that sets out responsibilities for offshore activities, such as fisheries, mining, shipping, navigation and crimes at sea. However, Commonwealth and the states/Northem Territory' fisheries legislation allow alternative arrangements to be made for a fishery that override the existing jurisdictional lines set out by the OCS.