crustaceans continue to be the most important species landed in in terms of value followed by shellfish and molluscs and tuna the number of people employed in the fisheries sector decreased between and the offshore constitutional settlement ocs is the jurisdictional arrangement between the commonwealth and statesnorthem territory that sets out responsibilities for offshore activities such as fisheries mining shipping navigation and crimes at sea however commonwealth and the statesnorthem territory fisheries legislation allow alternative arrangements to be made for a fishery that override the existing jurisdictional lines set out by the ocs