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Commercial Fishing



Fish stock could collapse if there is no Brexit deal. Fish stocks in British waters could suffer or even collapse if forthcoming negotiations between the UK and the EU fail to reach an agreement, according to research at the University of Strathclyde.

The study found that unilaterally-set fishing quotas could also lead indirectly to declines in the numbers of cetaceans – including dolphins and porpoises – and seabirds.

Fisheries will be one of the central themes of the talks aimed at securing agreement following the UK’s withdrawal from the Union and, consequently, the EU’s Common Fisheries Policy (CFP). Among the issues to be addressed will be quota arrangements for fish stocks. These will need to govern the sharing of Total Allowable Catch (TAC) between the EU and the UK, some of which are also shared by other nations such as Norway. TACs are based on independent scientific advice from the International Council for the Exploration of the Sea (ICES) and are designed to ensure that stocks remain at sustainable levels into the future.

The EU has asserted that preserving existing fishing quota arrangements will be essential to securing an overall post-Brexit deal. However the UK Government has identified the issue as a ‘red line’ in negotiations, maintaining that British boats must have increased quotas and priority in UK waters.

Researchers at Strathclyde used mathematical modelling to assess the possible consequences for fish stocks and marine wildlife of the UK and the EU both setting their own quotas – and the combined total exceeding the sustainable limit recommended by scientists. They found that unilateral quota setting would lead to around a 70% risk of North Sea herring and cod stocks falling to unsustainable levels within five years. The models also showed that whales and seabirds would be likely to decrease due to the reduction in their food supply.

Professor Michael Heath and Dr Robin Cook, both of Strathclyde’s Department of Mathematics and Statistics, co-produced the study.

Professor Heath said: “Our report shows the importance of observing scientific guidance on catch limits. It is vital that an agreement is reached between participants that preserves co-operation on fisheries, even in the face of political pressure to act independently for short-term gain.

“Otherwise, the outcome will be overfishing, eventual collapse of key stocks and declines in seabird and cetacean numbers, placing further pressure on the UK’s coastal communities that rely on a healthy marine environment to survive.

Dr Cook said: “Seabird populations are already under pressure from climate change and a diversity of human activities, so it would be detrimental to add further pressure from overfishing.

“The findings highlight the need for the UK to follow effective and auditable standards to ensure fishing limits are set at sustainable levels.”

Professor Heath and Dr Cook analysed data on fishery landings around the UK, particularly from the North Sea, since 1903. The distributions of landings across UK and non-UK zones in the North Sea were then compared with estimates for various species of ‘zonal attachment’ – the proportion of a shared stock which could be said to be ‘owned’ by a nation, based on the distribution of fish relative to its exclusive economic zone.

The assessments predicted that the greatest risks from talks breaking down, followed by unilateral arrangements, would be to plankton-eating pelagic fish, particularly herring. While risks to demersal fish as a whole would be lower, there would still be significant risk to cod.

The study sets out two plausible courses of events in a unilateral UK approach following breakdown of talks. One is based on TACs for individual species in the North Sea, in which the UK’s quota claims would rise by 72% for herring, 37% for saithe, 26% for sole, 16% for cod and 14% for whiting.

The other concerns a scenario in which the UK denies access to its waters to EU nations and Norway and the measure is reciprocated. In these cases, fishing would rise by 58% for pelagic species by trawling and netting, 20% for mackerel by long-line fishing and 6% for sandeel and sprat by trawling.

Cod and herring both have a history of stock depletion and are known to be vulnerable to collapse and the risks, particularly for cod, are even higher.

The study also notes that quotas for some species, especially shellfish, may not be affected by the UK’s departure from the EU since they are not covered by the EU Common Fisheries Policy but are instead already under national jurisdictions.