Should we still be eating fish?

We cannot easily see the destruction beneath the waves, but our once-abundant oceans are a scene of appalling wreckage.

The dawn of industrial fishing and ecologically destructive techniques such as dredging, bottom trawling and pulse fishing mean we have caught and killed about 90 per cent of the sheer weight of marine life that used to swim in the seas around Britain, according to the Marine Conservation Society.

The organisation is currently calling for a ban on bottom trawling, the main method used for catching fish including cod, haddock, plaice, monkfish, skate, hake and turbot.

Even with the most advanced fish detection technology imaginable, we now cannot find the fish we could easily harvest a century ago – the seas are barren.

A 2010 study published in the journal Nature found annual landings per unit of fishing power – a measure of the commercial productivity of fisheries – had collapsed by 94 per cent in the UK since 1889.

Seven years before that study, in 2003, a similar paper in the same respected journal warned: “Globally, 90 per cent of large fish are gone.”

The authors described their findings as “a grim global mosaic that demands immediate action”.

Despite countless warnings of this type, humanity has been unable to curb its inexhaustible desire for fish, and fishing efforts in the 21st century have only ramped up.

Boats have become bigger, demand has soared and the impact on the seas has grown to become a nightmarish industrial extermination programme.

The result today is a wave of supertrawlers capable of netting fish and pumping them on board through pipes for processing and freezing. These huge vessels, over 100 metres in length, may not have to land for months at a time and are now common around British coasts, even in the so-called “Marine Protected Areas”.

These ships can pull hundreds of tonnes of fish out of the sea each day, and with nets up to a mile long, the associated bycatch is of biblical proportions.

Supertrawlers spent 3,000 hours fishing in UK marine protected areas in 2019, during which more than 1,000 porpoises were accidentally caught and killed in their nets.

Boris Johnson has suggested these vessels – many of which are EU-registered – could be banned from UK waters after Brexit, although according to the terms of the deal this measure would also have to include UK-registered supertrawlers.

However, such a ban has not yet been confirmed and the Marine Management Organisation has already granted temporary licences to at least seven supertrawlers to continue fishing in UK waters.

It is not only the supertrawlers which represent a significant threat to biodiversity. Scallop dredging is a uniquely damaging process, worse to affected habitats even than bottom trawling.

In European waters, scallop dredging is almost always for king scallops which bury deep into the sand and sediment and have to be literally dredged up from the seabed with chains.

This process obliterates the delicate reefs resplendent with life, including other shellfish, corals, sponges, seaweeds and the vital nurseries where fish of innumerable variety lay their eggs.

So what about farmed fish? In 2018, the very last wild salmon fishery in Scotland, on the River Spey, closed because there were so few fish left to catch. With that closure, all Scottish salmon is now farmed.

One reason why there are now so few salmon in Scottish rivers is the modern prevalence of sea lice, which have flourished in farms and are easily transmitted to wild populations.

The fish farming industry is now under huge pressure to deal with surges in the lice affecting their stocks while mass mortality events have also become common because of algal blooms in warming waters.

Last year the world’s largest salmon farming company, Mowi, revealed the amount of gutted salmon it produced from Scottish waters had fallen by 36 per cent in a year, with infestations of sea lice and disease blamed.

What’s more, farmed fish still have to be fed – largely with other fish. This fishmeal, as it is known, is usually made up of rendered down low-value fish and, increasingly, processing offcuts from the fishery industry after the fish oil is pressed out of the same fish and other, more specialised high-value protein ingredients are removed.

Fish farmers are now increasingly turning to vegetable substitutes such as soy and rapeseed oil to replace the lost proteins and oils.

The farming process would naturally leave the flesh of salmon a dull grey colour, but in order to maintain the tantalising deep orange the human market desires, the fish are fed supplements designed to enhance their appearance on the supermarket counter.

Despite the grim overall picture, Sam Stone, head of fisheries and aquaculture at the Marine Conservation Society, told The Independent it is still possible for consumers to make seafood choices which have a low impact on the environment.

“The Good Fish Guide lets consumers make an informed choice and gives them the power to decide. To have the lowest impact, consumers should look for seafood that is rated 1 (out of 5) ‘Best choice’ on the guide,” he said.

“This includes farmed shellfish like mussels, oysters and scallops, and some very well managed wild capture fisheries like Marine Stewardship Council-certified hake and cod, and coley from Iceland, plus many more.”

He added: “Consumers can also keep an eye out for seafood that has been caught with certain techniques which have a lower impact on other species, like handline, pole and line, pot or trap or dive caught.”

Though there are glimmers of effort from some parts of the industry hoping to keep parts of the British fishing industry sustainable, and not all farms have the same problems outlined above, demand is still far beyond anything these more responsible factions can offset. The seas are emptying, many of the farms are appalling. How long are we going to keep demanding fish on the table?