Our government could stop supertrawlers from fishing in allegedly protected marine areas.
A "blue belt" of zones should be created around the UK to protect endangered fish species and help support sustainable fishing, according to scientists.
Researchers at the University of Southampton say that the opportunity for new fishing policies created by the Brexit negotiations combined with reduced fishing during the Covid-19 pandemic offers the chance to restore fish levels.
The study, which was carried out jointly with the GEOMAR Helmholtz Centre for Ocean Research and the University of British Colombia, shows that the reduction in fishing activity during the pandemic has seen pressure on some threatened species fall to levels not seen since the Second World War.
The researchers highlight that as the UK will no longer be bound by the EU's Common Fisheries Policy it has a chance to develop a new policy focused on sustainability.
Lead author Professor Paul Kemp, from the University of Southampton, said: "Several stocks targeted by UK fishers are in a degraded and precarious state, with around 40% that will continue to be over-fished when normal activity resumes.
"One of the reasons for this is that fishing quotas - or how much of each species can be caught in a certain area by each country - are set by the EU at levels higher than those that would enable the recovery of the populations."
The researchers propose fishing targets should be set to levels in which fishers leave more fish in the water than the minimum required to generate maximum sustainable yields.
And they suggest the creation of the "blue belt" of Marine Protected Areas to further protect vulnerable fish populations.
Co-author Daniel Pauly, from the University of British Columbia, said: "The opportunity to do this is now because of the slowdown caused by Covid-19.
"After Brexit, the UK will be in a position to insist in its negotiations with the EU that fishing quotas advised by scientists not be exceeded."
He added: "The establishment of MPAs is one of the most cost-effective ways to restore over-exploited stocks and habitats on which fish depend, to the mutual benefit of the fishing industry who experience increased catches in grounds immediately outside of MPAs."
Professor Kemp added: "UK politicians have the chance to bring people together over a common goal that supports fishing communities, wider society and environmental sustainability.
"The opportunity is there but it will require political vision; with the necessary strength of character, the negotiators can deliver a positive outcome from the combined systemic shocks of Brexit and Covid-19."
Chris Thorne, an oceans campaigner at Greenpeace UK, said: "Our departure from the Common Fisheries Policy provides our government with a unique opportunity to fix the broken system of marine paper parks, most of which are protected on a map but not in reality.
"A blue belt of properly protected marine areas would give marine life a chance to recover and ensure that the UK's oceans can thrive, which will help support our struggling coastal communities by boosting fish populations.
"Our government could start by stopping industrial supertrawlers from fishing for thousands of hours every year in allegedly protected marine areas."
Ben Mitchell is a reporter with PA.