National Limits
Terrotorial Sea Limits
Initially, Irish fishing limits extended to the old Irish territorial sea limit, i.e. three nautical miles from the baselines. The Maritime Jurisdiction Act declares that the exclusive fishery limit of the State comprises all sea areas lying within the outer limit of the territorial seas.
Legislation allowed the government by statutory instrument to extend the exclusive fisheries limit. The State is authorised to include in the definition of the fishery limits a wider area of sea than that laid down in the Act where any international agreement so allows.
The government having regard to international agreements to which it is party and, if satisfied that it is necessary to do so to maintain the productivity of living resources, prescribes and adopts measures for conservation as they think appropriate to any stock of fish or other marine resources in any area of the high seas adjacent to the exclusive fishery limit. No order was made under this provision as it intended to refer to a conservation convention to which Ireland did not become a party.
Fishing Limits
The Maritime Jurisdiction Amendment Act 1964 was intended to enable Ireland to ratify the European Fisheries Convention and extend fishing limits to 12 miles beyond the three-mile territorial sea. The principle of the Fisheries Convention was that the coastal state would either have exclusivity or priority fishing rights. A 12-mile fishery zone was becoming customary at the time and was recognised by the Convention. Accordingly, the 1964 Act extended the limit to 12 miles.
Sea-Fisheries and Maritime Jurisdiction (Amendment) Act 2019 continues to assert Ireland’s exclusive right to fish within the exclusive fishery limits of the State by maintaining previous provisions but also explicitly provides for access to fish by sea-fishing boats owned and operated in Northern Ireland within 0 – 6 nautical miles of the baseline of the State’s exclusive fishery limits.
It further provides that Northern Ireland sea-fishing boats will be subject to the same obligations as an Irish sea-fishing boat while availing of the access conferred by the Act in keeping with the reciprocal Voisinage arrangements for fishing between Ireland and Northern Ireland and the Government of the United Kingdom.
The European Union has primary powers in fisheries matters. In 1976 Ireland extended its exclusive fishery zone claim to 200 miles in conjunction with EU steps. The zone was defined in detailed in ministerial orders. The 200 miles is measured from the baselines.
The Irish extensive fishery limits extend out in a double arch shape from the western coast of Ireland. This is subtended by a line from the United Kingdom on the northeast and southeast sides.
Rockall & UK /Irish Issues
The United Kingdom purported to declare a 12-mile exclusive zone around Rockall in 1964. In the 1970s, the United Kingdom aimed to assert a 200 mile exclusive economic zone around Rockall.
A 1988 agreement with the UK on the continental shelf does not deal with fishery matter, so the 12-mile exclusive fishery around Rockall remains unaffected/unresolved.
However, the United Kingdom has effectively rolled back its position in relation to Rockall after acceding to the Law of the Sea Convention in 1997, which accepts that Rockall was incapable of generating a 200-mile extensive economic zone. The effect was that some significant areas of British/EU waters reverted to high seas status.
A 2013 Agreement built on the 1988 Agreement between Ireland and the UK that had already established continental shelf boundaries. The boundaries, slightly adjusted to ensure that no waters were lost to the high seas, are also the EEZ boundaries. This created a single maritime boundary between 12 and 200 miles in the water and on the seabed beneath.
Irish 12 Mile Zone
Certain states had rights to fish in the 6 to 12-mile zone for certain species under mutual agreements between Ireland, Belgium, United Kingdom, Germany, Netherlands and Spain.
The European Fisheries Convention phased out states who could habitually fish in the three to six miles zone. Fishing rights in the six to twelve-mile zone were given to states whose fishermen had habitually fished between 1953 and 1962 in certain areas and subject to certain conditions.
Under EU access conditions, Ireland was authorised to restrict fishing within the six-mile zone to vessels which traditionally fished in those waters and operated from ports in that area. At the end of the transitional period after 10 years, Ireland acquired a 12-mile exclusive zone. This remains subject to the pre-existing Fisheries Convention rights of access for certain other states to which the Irish zone is subject. Irish fishermen have corresponding rights in other states’ exclusive areas.
Spanish vessels acclaimed certain customary rights of fishing in Irish waters, including, in particular, the Celtic Sea. For a period of 10 years after Spanish accession to the EU in 1986, a  derogation was allowed excluding Spanish vessels from the so-called Irish Box. This period has now ended.
The result of the above is that the Irish fishermen have exclusive rights in the six-mile zone, and certain foreign fishermen from the above Convention states have restrictive customary rights in the 6 and 12-mile zone derived from traditional fishing.
There is a de facto arrangement between the Republic of Ireland and Northern Ireland (but not the rest of the United Kingdom). Northern Ireland fishermen are permitted to fish in all areas of the Republic of Ireland’s limits subject to Republic of Ireland laws. Specifically, Republic of Ireland fishermen are permitted to fish in Northern Ireland waters on the same terms.
Fisheries Enforcement
Ireland is obliged under EU fishery enforcement rules and internationally to enforce fishery regulations within its own jurisdiction. This allows boarding, inspection, arrest and prosecution to ensure compliance. The matter of enforcement of EU law is a matter for the EU states in the waters under its jurisdiction under the conservation rules, which are harmonised within the EU.
The Fisheries Amendment Consolidation Act allows fishery protection officers who may be, in effect, members of the  Naval Service the right to stop and arrest fishing boats. After giving a warning shot, it may take action against a boat which is disobeying a lawful order. This is subject to the rules of international law, which require proportionality.
EEZ Minerals Research Pollution
In the exclusive economic zone, the coastal state has jurisdiction in relation to minerals, navigation, scientific research, and pollution. The Law of the Sea Convention contemplates rights, including rights of exploration, exploiting, conserving and managing the national resources, including living and non-living on the seabed and subsoil in adjacent waters and other activities for the economic exploitation and exploration of the zone, such as energy production from water, currents or wind.
The rights include setting up installations for scientific purposes, weather forecasts, and other purposes. The rights in the EEZ are subject to the remaining rights of other states in the EEZ, including freedom of navigation, oversight, freedom to lay cables, pipelines and other international lawful uses.
EEZ & Fishing
Under the EEZ regime, third-party states have access to surplus stocks of the allowable catch. The coastal state is obliged under the Convention to decide its capacity to harvest the living resources of the area and give access to such surplus to another state where it does not have the capacity to harvest the entire allowable catch.
The EU supports the Law of the Sea Convention position, which allows landlocked and disadvantaged states to participate in the exploitation of surplus fish, but not other non-living resources in the EEZ area if the coastal state does not have the capacity to harvest its allowable areas.
The Common Fisheries Policy provides for the exploitation of the natural resources waters in accordance with the Law of the Sea Convention as a single unit.
The EEZ places an obligation on the coastal state to preserve natural resources, whether living or non-living. There is an obligation to protect the general and marine environment.
Certain marine species are protected under the Habitats Directive so that the duty to protect them evolves on the states.
The nationals of other EU states within the EEZ were subject to conservation measures and other terms and conditions of the coastal state. The coastal state may take measures, including arrest and proceedings, to ensure compliance with the laws and regulations adopted by it in conformity with the Conventions.
The coastal state is empowered to provide legislation to regulate good order in relation to fishing activities. The provisions of the Fisheries Consolidation Act are available and applicable if they were so extended to the EEZ zone.
North Atlantic Convention
The Convention on Conduct of Fisheries in the North Atlantic applies to seas around Ireland. Its purpose is to ensure good order and conduct in fishing grounds. Ireland signed but has not ratified the treaty. The Fisheries Amendment Act 1970 allows for ratification and for the making by the Minister of the requisite regulations thereunder.
The Convention provides that in the area where the coastal state has jurisdiction over fisheries, the implementation and enforcement of the Convention is the responsibility of the coastal state.
The duty to enforce and implement requires the prescription of offence within the fisheries jurisdiction and enforcement. This may include provisions requiring registration and markings of fishery gear subject to compliance with commission regulations.
Vessels must conform with the provisions of the Convention. State parties are allowed to make provisions subject to compatibility with international collision regulations.
Marine Research
The UN Convention on the Law of the Sea provides that all coastal states have the exclusive right to regulate, authorise and conduct marine scientific research in their territorial seas and exclusive economic zones and on their continental shelves.
Requests for authorisation by foreign vessels are considered by the Marine Institute in consultation with relevant agencies and Departments. Applications for research cruise authorisation should be submitted through the diplomatic channel by the flag state of the vessel from which it is proposed to conduct research.