A recent report by the ocean charity Blue Marine Foundation has highlighted significant declines in several key fish populations around the British Isles, attributing the trend to fishing quotas set above scientifically recommended levels. The findings raise concerns about the sustainability of UK fish stocks nearly a decade after Brexit, a period some had viewed as an opportunity to improve fishery management.

The report analyzed stock assessment data from the International Council for the Exploration of the Sea, comparing mature fish biomass estimates in British waters from 2016 to 2025. Among the steepest declines, Irish Sea plaice saw an 88% drop, falling from approximately 20,952 tonnes to 2,590 tonnes. Celtic Sea cod experienced a 98% decrease in mature biomass over the same period. Additional species such as herring in the West of Scotland and mackerel in the northeast Atlantic also showed substantial population drops, recorded at 93% and 78% respectively.

In contrast, some species demonstrated population increases. Sole, seabass, and boarfish have risen in certain areas, as has haddock in the North Sea and Rockall, though haddock stocks have declined in the Irish Sea. Overall, the report indicates that the UK government has consistently set catch limits that exceed scientific advice, raising concerns from conservation groups about the long-term viability of these fish populations.

Since Brexit, the UK has had greater autonomy in negotiating fishing quotas, which it does annually in coordination with the European Union, Norway, and other neighbouring nations for up to 80 fish stocks. Despite this increased control, Blue Marine Foundation contends that not a single year since the UK's departure from the EU has seen the majority of catch limits align with sustainability guidelines.

Jonny Hughes, fisheries policy lead at Blue Marine Foundation, criticized the continued disregard for scientific advice, suggesting that political considerations have influenced quota decisions at the expense of marine ecosystems and the fishing industry’s future. The foundation asserts that the ongoing management approach prioritizes short-term interests over essential long-term recovery goals.

UK authorities have expressed commitments to maintaining a sustainable fishing industry alongside a healthy marine environment. However, critics argue that measures implemented thus far have been insufficient to halt or reverse the trends of declining fish populations, calling for stricter adherence to scientific recommendations in quota-setting to safeguard marine biodiversity and fishing livelihoods.