A basic principle is that the coastal state has jurisdiction over its territorial seas. It has a right to explore, exploit and conserve and manage fishing in any EEZ and EFZ it may claim. Beyond this and in the high seas, fishing is open to all, subject to the jurisdiction of the flag state.
Overfishing has been a major problem in recent decades. Many important stocks are endangered. A number of regional fisheries bodies and management organisations have been formed to conserve, manage and develop fishing stocks. There have been controversies, when some states have sought to push out their enforcement rights to 200 nautical miles and sought to enforce jurisdiction over vessels of another flag.
The vast majority of fishing takes place within EEZs. Under the Law of the Sea Convention, the coastal state does not enjoy a monopoly or unlimited right to exploit fishery resources. The Law of the Sea requires states to determine the allowable catch. They must ensure a proper conservation and management of living resources. They must ensure that they are not endangered by overexploitation.
The measures must maintain and restore population of harvested species which can produce the maximum sustainable yield. They must promote the objective of optimum utilisation of living resources of the EEZ. The coastal states must determine the capacity to harvest the resources. Where this is short of the allowable catch, the coastal state must give other states access to the surplus.
They must have particular regard to the circumstances of developing states as well as the interest of landlocked and geographically disadvantaged states in determining to whom access should be granted. In practice, however this is not limited the control of the coastal states over the EEZ fishery resources.
The freedom to fish in the high seas is not unlimited. The Convention on Fishing and Conservation of Living Resources of High Seas recognises the special interest of the adjoining coastal state in fishing in areas adjoining its territorial waters. Conventions provide specific rules for certain categories such as salmon, which spent much of their time at sea but spawn in freshwaters.
The Law of the Sea Convention provides that the freedom in relation to the high seas is subject to the interest of the coastal states in certain classes of species set out in the Convention. It provides a general obligation to preserve the living resources of the high seas by placing caps on the allowable catches on the basis of sustainability.
The Law of the Sea Convention requires that states whose nationals exploit living resources in the same area are to enter into negotiations with a view to taking measures necessary for conservation of the living resources concerned. They must cooperate to establish regional and sub-regional fisheries organisations for this purpose. The North Western Atlantic Fisheries Organisation and the Commission for the Conservation of Antarctic Marine Resources have been established.
The Convention calls for cooperation in relation to certain highly migratory species and straddling stocks which can move to many different zones and the high seas. The UN Agreement on Straddling Stocks and Highly Migratory Species obliges states whose nationals fish for stocks to become members of fishery management organisations or agree to take measures in accordance with those established by the organisation. The states may not fish for stocks outside of the framework established by the organisation.
Where regional fisheries management organisations exists, inspectors of any states are authorised to go on board and inspect fishing vessels flying the flag of other states to the Convention to ensure compliance with the conservation and management provisions established by the organisation. Where there are clear grounds for suspecting that serious violations have occurred, the vessel may be taken to the appropriate port. This enforcement action may only be taken by the flag state or with its consent.