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Bottom trawling: how to empty the seas in just 150 years

Fishing Trawler in North Sea

A trawler on the North Sea between Scotland and Norway. Even with modern technology, catches are just 6% of what they were 120 years ago. Photograph: Tina Norris/Rex


Powered by article titled “Bottom trawling: how to empty the seas in just 150 years” was written by Robin McKie, for The Observer on Monday 10th February 2014 09.00 UTC

“I believe there is not a portion of the ground but what the trawl destroys,” explained G Cormack, a fisherman from Torry, Aberdeen. “I have dragged 50 miles off Aberdeen. I have got fast there and brought up coral about 2.5ft in circumference, lumps of soft coral, and I am prepared to say that whatever is in the way of the trawler will not escape.”

It is a stark description of the damage inflicted by “bottom trawling”, the practice of dragging heavily weighted nets across the seafloor to sweep up fish – like cod and haddock – that thrive there. And it is all the more alarming for having been voiced almost 150 years ago. Cormack was giving evidence in 1866 to a royal commission on the impact of bottom trawling, which expanded massively in British waters from the beginning of the 19th century. Traditional fishers opposed bottom trawling, not just because they thought it damaged the seabed by ripping up coral, oyster beds and sponges, but because they believed it wiped out fish stocks. “Twenty years ago, we used to get 600 or 700 a head of fish a day,” said another commission witness, B Simpson, a line-fisherman who worked off Spurn Point, Grimsby. “Now they cannot get above 20 head, or three or four score at the outside.”

At the hearings, hundreds of others gave evidence, most of them damning in their views of bottom trawling, as is revealed in a recent paper by York University’s Ruth Thurstan, Julie Hawkins and Callum Roberts in the journal Fish and Fisheries. The evidence was to no avail, however, for the commission decided Britain could not afford to block bottom trawling and so decreed that “unrestricted freedom of fishing should be permitted”. The fishing industry lobby in Victorian times was clearly no less powerful then than it is today. These 150-year-old tales of ruined fish stocks and wrecked seabeds have a special irony for modern marine biologists and ecologists – for just as the 1866 royal commission turned its back on trying to protect the UK’s marine environment, so the government today stands accused of allowing our coastal seas to be degraded to an even greater extent. Indeed, the marine devastation of the 19th century looks relatively minor compared with that of today. In the 19th century, and even in the early 20th century, bottom trawling was done by fisherman sailing 40ft wooden boats – usually owned by a single family – which dragged nets with mouths a few metres wide across the seafloor, sweeping up shoals of cod, haddock and herring. “It would have been a very tough existence,” says Angela Benn, of the National Oceanography Centre, at the University of Southampton. “You were going out in all sorts of weather. It took incredible bravery and the loss of life was grim.”

And it caused considerable damage to the seabed and triggered significant depletions of stocks, as the commission heard. The trouble is that these relatively modest-sized trawlers have been replaced by far, far bigger ships operated as industrial concerns by business conglomerates. They use vast, 30-tonne nets that have metal doors and chains to hold them down and are dragged across the seabed with effects that far outstrip those described by Cormack, Simpson and other 1866 commission witnesses.

“Imagine if you used a fleet of tractors to drag 30 tonnes of gear over a 150-metre wide swath of land for most days of the year,” says Brian Bett, another marine researcher at the National Oceanography Centre. “You would wipe out the New Forest in a few months and the rest of the countryside not long after that. Yet that is what we are doing to the seabed round Britain. Even worse, the boats keep going over some key areas. The seafloor gets no chance to recuperate. It is tragic.”

Not surprisingly, the impact on reefs, sponges and shellfish has been savage. The Firth of Forth was once home to vast beds of oysters, for example. None remains. Similarly, the Firth of Clyde once abounded with fish, shellfish, whales and porpoises. Today its seabed is barren and its fish stocks have disappeared. “Nothing worth catching is left,” states Callum Roberts in his book, Ocean of Life. “The Firth of Clyde gives us a stark vision of a life without fish.”

And as bottom trawling and dredging continues, such a fate awaits most other UK inshore fisheries. “Trawlers have transformed life on the seabed, converting three-dimensional, complex habitats rich in coral, sponge and sea fan to endless monotonous expanses of shifting gravel, sand and mud,” adds Roberts. Nor is the damage confined to the seabed. Stocks of fish – robbed of any hiding places on the seafloor – have suffered correspondingly. Common skate, angel shark, halibut and wolfish, once plentiful, have virtually disappeared from British waters while bottom fish – which cling to the seabed – such as cod, haddock and turbot, have suffered drastic declines in numbers.


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