One of the most dramatic impacts on marine life came from the advent of bottom trawling. In 1376 a complaint was made to King Edward III about the destruction it caused:

“Where in creeks and havens of the sea there used to be plenteous fishing, to the profit of the Kingdom, certain fishermen for several years past have subtily contrived an instrument called ‘wondyrechaun’. . . the great and long iron of the wondyrechaun runs so heavily and hardly over the ground when fishing that it destroys the flowers of the land below water there, and also the spat of oysters, mussels and other fish up on which the great fish are accustomed to be fed and nourished. By which instrument in many places, the fishermen take such quantity of small fish that they do not know what to do with them; and that they feed and fat their pigs with them, to the great damage of the common of the realm and the destruction of the fisheries, and they prey for a remedy.

Anger greeted the trawls where they were used, for the local fishermen could see the damage that they caused to their favourite areas. Bans were introduced to try to stop their use, and in 1583 two fishermen were executed for using metal chains on their beam trawls (today these are standard issue).

But the new method spread, for it was brutally efficient in the short term, even if unsustainable. Over generations fishermen began to accept the new status quo and forgot what the seas had once been like.

A Royal Commission in 1863 was established to investigate the accusations against trawling, among other complaints. One of the arguments presented by the defence was a witness who, when asked what food fish eat, replied:

“There is when the ground is stirred up by the trawl. We think the trawl acts in the same way as a plough on the land. It is just like the farmers tilling their ground. The more we turn it over the great supply of food there is, and the greater quantity of fish we catch.

The same reasoning is argued today. “Because the ground is being turned over, food is there for them,” the owner of two beam trawlers in Brixham, Devon, told me last year. The concept was appealing enough to influence the 1863 Royal Commission to abandon more than 50 Acts of Parliament and open the seas to unrestricted fishing.

The stirring up of the seabed provides nutrients for certain bottom-dwelling fish. But the ocean is not a farm with grazing cows, it is a wilderness filled with fish. The Royal Parks were established to maximise the size and profusion of wild game for the King and his consorts. They were not ploughed but left alone to encourage the full, three-dimensional productivity of the forest.

With the arrival of trawlers powered not by sail but steam, then diesel, their destructive potential became magnified. As a result, the delicate structure of life on many, deeper and more distant areas of the seabed is a distant memory.

But as the Census of Marine Life shows, history is powerful. May it lead us back to the seas of days gone by.

- This case study is drawn from The Unnatural History of the Sea by Professor Callum Roberts (Gaia 2007).

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