The boats supplying the fish we eat are killing dolphins so fast that they are heading towards extinction.
By George Monbiot, published in the Guardian 12th March 2020
How many people want dolphins killed?
Apart from the psychopath shooting them in Florida, and the Japanese hunters slaughtering them every year in Taiji Cove, I would hazard a guess at none. They are perhaps the world’s most-loved wild animals. Yet, every day, dolphin killers form an orderly queue, at supermarket checkouts in the UK and around the world. If you are buying fish, and there is no clear and watertight guarantee, you are likely to be complicit in something that would revolt you.
A horrifying report last week shows that dolphin numbers in the Indian Ocean have fallen by some 87% since 1980, as they’ve been drowned in gillnets set for tuna. But the problem is not confined to distant seas, or to tuna fisheries. On average, two dolphins or porpoises are washed up on UK beaches every day. Many of them show the scrapes and indentations caused by fishing nets. Discoveries of dead dolphins around the Bay of Biscay this year are likely to beat the grisly record set in 2019, when 1,100 were found on the French coast. Large numbers are also turning up on the beaches of Ireland.
Not every dolphin or porpoise that washes up dead has been killed by the fishing industry. Infections are more prevalent than they were before, perhaps as a result of persistent synthetic chemicals accumulating in the animals’ tissues and suppressing their immune systems. But in many places, including the Bay of Biscay, Ireland and probably the English Channel, industrial fishing appears to be the biggest cause.
The dolphins found on the shore are likely to be a small proportion of the total killed. Most corpses sink or drift out to sea. Because the slaughter is deliberately unrecorded by European governments, we have only rough guesses about how many might be dying. One scientific estimate suggests that around one eighth of the slaughtered dolphins are likely to appear on beaches. Dolphins are long-lived and reproduce slowly. In the north Atlantic, the common dolphin calves only about once every four years. The unquantified mass slaughter caused by fishing boats, if it is allowed to continue, is likely soon to drive them to extinction.
Almost all commercial fishing presents a threat to dolphins and porpoises. But some techniques are more lethal than others. While gillnets kill large numbers of porpoises, and all kinds of trawling and purse seining endanger dolphins, there’s a particularly strong correlation between dolphin deaths and two types of fishing: pair trawlers catching bass, and supertrawlers pursuing small, midwater fish.
Pair trawlers (two boats pulling a net between them) move much faster than single trawlers. Supertrawlers – ships 100 metres or more in length – tow gigantic nets that scoop up entire shoals, and the predators hunting them.