By Philip Lymbery

WE have heard much of cruelty to farmed fish in recent times. Take, for example, the incident reported in November of last year, where 175,000 Scottish farmed salmon died after a treatment designed to rid them of sea lice — which latch on to fish and eat away at the skin and scales — proved fatal.

The procedure involves plunging the fish into heated water, so you can imagine the shock to the system this would entail for creatures who are accustomed to the ice-cold sea. This embarrassing blunder put the fish farming industry under the spotlight for their failure to find an effective solution to the sea lice problem which is plaguing it.

As if the suffering endured by these complex and under-valued animals wasn’t enough, there is another grim force at play in the farmed fish industry. In 1883, the great British scientist Thomas Huxley declared that ‘all the great sea fisheries are inexhaustible’ and that ‘nothing we do seriously affects the numbers of fish’.

We now know that this is crushingly untrue. Scientists are currently predicting that the world’s fisheries will have depleted by 2048. How far we’ve come, in just a hundred years or so. The cause, in no small part, is the commercial fishing industry.

Very few consumers are aware of this, but vast swathes of wild fish are caught around the world to feed intensively farmed animals here in the UK – in particular fish such as salmon, but also pigs and chickens. They are ground down to produce what’s called “fishmeal”.

A large part of the global fishmeal catch is made up of small, pelagic fish such as anchovy, sardine, and sand eel. Being the primary source of food for many species, these fish are crucial to the ocean ecology.

Seabirds, for example, depend on pelagic fish. Puffins from Shetland and penguins from South Africa, Peru and the Galapagos Islands, to name but a few, survive on fishmeal species. Annually, over 17 million tonnes of them are removed from the ocean by fisheries worldwide — an estimated 90 billion individual animals.

Peru is the single biggest player in this game, producing a third of the world’s total fishmeal for export. Much of it goes to feed industrially reared farm animals in Europe and China. The UK alone imports up to 100,000 tonnes of fishmeal a year, about a third from Peru. Fishmeal amounts to a staggering 27 per cent of the total global fish catch.

Take that in for a minute: nearly a third of the fish we catch goes to feed the fish we farm, among other animals.

I had long dreamed of visiting Peru — one of the most species-rich places on the planet — and the opportunity to turn dream into reality came a few years ago. My anticipation would sour into despair as I discovered the devastating impact of commercial fisheries on wildlife there.

The Humboldt penguin, which breeds in Peru, has suffered a shattering decline in numbers, from a million birds to fewer than 30,000 now. Other seabird numbers in Peru have plummeted by 90 per cent.

The problem is, anchovies in Peru — which Humboldt penguins feed on — are being gravely overfished. It’s upset the long-standing balance between predator and prey. Now there’s a new kid on the block, and he doesn’t play nice. Put simply, there’s not enough food left for the penguins. We’re stealing it to fuel our cruel factory farms.

The puffins of Scotland suffer a similar fate. They feed mainly on sand eels – a small fish which is the puffin chicks’ daily bread. Sand eels have been heavily overfished in the North Sea and are now in very short supply. Between 1994 and 2003, some 880,000 tonnes were removed. There has been an approximate 20 per cent decline in the number of chicks fledged per puffin pair in the decade leading up to 2016, which correlates with a decline of around two-thirds in the weight of fish loads brought to puffin chicks on Fair Isle, Shetland, during the same period.

Europe’s puffins are now classified as globally “endangered” by the IUCN Red List and are predicted to decline by nearly 80 per cent by 2065. There are clear links between the intensity of sand eel fishing in the North Sea and the decline in seabird populations.

As the commercial fishery prospered, so seabirds and other marine life dwindled. Nothing was a match for the hungry new competitor hoovering up the same little fish other creatures rely on for food. It’s a disaster for the sand eels and puffins alike.

The ecosystems of this world are delicate and balanced phenomena. For years the food chain remained relatively stable, but with the arrival of massively industrialised farming technologies and human greed to match, a collapse was inevitable.

When you remove or damage just one element of this intricate chain of links, the repercussions are endless. They may not be immediately visible, but they are there. And eventually, we will have messed things up so much, the chain of repercussions will reach the human race itself. And then, perhaps, we will begin to take notice. But will it be too late?

Seabirds are far from the only victims of the reckless looting of the world’s oceans to feed factory farms: human food supplies also suffer. In the last half-century, about 90 per cent of the world’s big fish – those we put on our plates – have been taken for food or discarded, leaving oceans close to collapse.

When there are so many other varieties of food available to us which don’t involve this senseless destruction, what gives us the right to keep on harvesting the sea and snatching food away from wildlife?

Where the Wild Things Were by Philip Lymbery, pictured above, is published by Bloomsbury, priced £12.99 and is available on March 9.