Whenever we ask what else you would like to buy from Riverford besides veg, the answer is always ‘fish’. So, with Brixham (England’s biggest fishing port) just 15 miles away, we started asking for a definition of sustainable fishing. After meetings with fishers, traders, environmental organisations and marine biologists, the only method all could agree on was line-caught fish from day boats under 10m long.

Fishing with lines from a static boat avoids the damage to the sea floor caused by beam trawling, and allows you to target sustainable species (unlike indiscriminate nets), as well as reducing pollution and saving on fuel. This method accounts for a fraction of UK fish, and is highly weather and season dependent, which is why we have such a limited offer. Anyone offering you a continuous range of fresh, day boat-landed fish is lying, but don’t be surprised; this is a murky industry, where regulation has failed, and lying and illegality are endemic.

Last night I watched Seaspiracy (the Netflix documentary on the impact of fishing). Despite hating the film’s out-of-context quotes, misleading statistics and generalisations, I found it hard to disagree with the main conclusion: that there is almost no sustainable fishing, and the labels claiming sustainability fall a long way short of delivering it. Beam trawling destroys the sea bed, causes more CO2 emissions than the entire global aviation industry, and contributes to the 10-50 per cent (depending on where/how you measure it) of marine plastic that is derived from fishing tackle.

Drift nets are too often lost, entangling and killing wildlife. And this is all before you consider the effect on the target fish, and the by-catch, including marine mammals. Who could possibly argue that this is sustainable? Although, I am painfully aware that a fisher could say the same about 99 per cent of agriculture.

So should we just not eat fish, as the film says? I would argue that, just like in farming, we need effective, enforceable, national and international regulation – not misleading labels and uncontrolled market forces. We need marine reserves where all commercial fishing is banned. Disturbance of the sea bottom should be illegal. Quotas need to be redistributed to smaller, local boats. Plundering of fish stock in the developing world by large foreign boats must stop, and fossil fuels must be taxed. If that is politically undoable, then yes, we should stop eating fish.

On a brighter note, it seems you can eat as many (non-dredged) mussels as you like.