The Irish fishing industry will lose €43m worth of quota share by 2026 under the EU-UK free trade agreement, according to preliminary figures published by the Government.
This will amount to a 15% reduction in the overall value of Irish fish quotas compared to 2020.
Figures show that of the eight EU coastal states which have historically fished in UK waters, Ireland and Germany will be hit hardest by the Brexit deal, in terms of the proportionate loss of quota share to the UK.
The mackerel sector, which is the most valuable to the Irish fleet, will be hardest hit, with a 26% cut in Ireland's quota share, worth €28.6m.
The share in prawn stocks will be cut by 14% by 2026, a loss of €8.2m.
Irish vessels fishing whitefish in the Celtic Sea will lose €3.4m and €0.5m in the Irish Sea, while off western Scotland there will be a loss of whitefish stocks worth €2.2m.
There will be a 96% cut in the herring quota in the Irish Sea, while several smaller whitefish quotas in the Donegal/west of Scotland area have seen sizeable quota share reductions, according to the figures, which were compiled by the Department of the Marine with support from the Marine Institute and Bord Iascaigh Mhara.
The deal struck on Christmas Eve between British and EU negotiators foresees an overall cut to the value of fish caught by EU boats in UK waters worth 25%, with a phasing in period of five and a half years.
Some 60% of the reduction will come between 2020 and 2021.
The figures show that both Ireland and Germany will lose 15% of the value of their quotas once the shares have been ceded to the UK by 2026.
The Netherlands will lose 10%, France will lose 8%, Denmark and Belgium will lose 7%, and Spain will lose 4%.