School of Fish Underwater-Photo by Engin


Fish are too often forgotten when it comes to treating animals kindly, but more people are realising that eating fish and other sealife means supporting cruelty and environmental disaster.

Until fairly recently humankind considered fish such an inexhaustible resource that we did not even count how many we were catching. The first such attempt to do so came about in a 2010 study,Worse things happen at sea: the welfare of wild-caught fish. Using the reported tonnage of caught species, and dividing by the average weight of each species, author Alison Mood estimated the global capture of wild fish at 1 to 2.7 trillion per year. This does not even account for the number of fish caught illegally or as bycatch, and in the case of the latter, estimates indicate that fully 40% of fish caught worldwide are actually caught unintentionally, which would add significantly to the total.[1]

The above number also does not include the millions of fish who suffer on fish farms, which are in and of themselves an environmental travesty responsible for ocean dead zones and rampant disease in wild marine life.

Learn about all these issues--and more--below.


'The claim that fish "do not have the right sort of brain" to feel pain can no longer be called scientific.'

--Professor John Webster of the University of Bristol



Despite what public perception might indicate, there is no longer any debate in the scientific community as to whether fish feel pain. They produce the same opioids that mammals do, and their brain activity during injury is the same as that of terrestrial vertebrates; stick a pin behind the fin of a fish and the brain regions associated with conscious sensory perception (as opposed to reflex and impulse) respond. The pain system of fish is very similar to that of birds and mammals, and in fact, fish respond to pain in the same manner as birds and mammals do: they behave in ways suggestive of pain, act differently for hours afterwards, and even learn to avoid places or situations that have caused them pain in the past.[2] Dosing the fish with painkillers, however, reduces these responses.[3]

In a series of studies requested by the European Commission, the Animal Health and Welfare panel reported that the stress response in fish is "directly comparable to that of higher vertebrates" and that "responses of fish... suggest that they are able to experience fear." These studies, which measured physiological variables such as cortisol, a steroid hormone naturally released in response to stress, demonstrated that fish do experience stress and fear when caught and when killed.[4]


No fish gets a good death. Not a single one. You never have to wonder if the fish on your plate had to suffer. [They] did.

Jonathan Safran Foer, Eating Animals



Traditional methods of slaughter were chosen purely on the basis of cost and ease; simply removing fish from water, for example, causes them to suffocate. They struggle desperately, showing 'violent escape behaviors accompanied by maximum stress responses' as their gills collapse.[5] One study, which focused on several species of wild fish, including cod, herring, and sole, found that it took anywhere from 55 minutes to over four hours for the fish to die once removed from water.[6]

When wild fish are not simply left to suffocate or be crushed under the bodies of other fish, they are commonly eviscerated, or gutted, whilst still alive. This reduces the duration of their suffering, but not as much as we might expect: one study carried out on several species found that it was still 25 to 65 minutes before the gutted fish became 'insensible.'[7]

And according to an account from Juliet Gellatley, director of Viva!, it can take much longer:

To find out about fishing I once sailed on a trawler...worst of all was what happened to a big orange-speckled flat fish—a plaice. It [sic] was tossed into a bin with other flat fish and four hours later I literally heard it croaking. I pointed out to one of the deckhands who, without even thinking about it, clubbed the fish... Six hours later I noticed that its mouth and gill covers were still opening and closing as it struggled for oxygen. Its misery had lasted ten hours.

Wild fish may suffer in an additional way before they are taken from the water. For example, long-line fishing is a popular method of capture which uses hundreds or thousands of hooks on a fishing line that can be anywhere from 50 to 100 kilometres in length. Fish and other animals who take the bait are likely to remain caught and dragged along for hours before the line is hauled in.

Bottom trawling, the other main method of catching wild fish, entails dragging a heavy, weighted net along the ocean floor that simply scoops up everything in its path. It is incredibly destructive in its efficiency and like longline fishing, wholly indiscriminatory as to who--or what--it catches.  Not surprisingly, bottom trawling is responsible for significant damage to the sea floor.

It is also important to note that just like slaughterhouse work, the fishing industry is rife not only with animal abuse but human exploitation.



Some people claim that farming fish is a solution to our rapidly depleting oceans. Farm-raised fish, however, has been described in the New York Times as 'the cage-raised chickens of the sea' and 'as much a part of the industrial food chain as a fast-food burger'.[8],[9] What's more, it now accounts for more than half of the fish people eat.[10]

Take salmon, which is no longer fished commercially in the UK; it all comes from Scottish farms. They've been praised as being environmentally sustainable, but how true is this claim? (First, let's note that in the case of carnivorous fish like salmon, it takes three to four pounds of wild-caught fish meal to produce just one pound of farmed fish: about one-fifth of the fish we catch in the wild goes to feed farmed fish.)[11],[12] More than 200 farms in Scotland and the Northern Isles contain hundreds of thousands of these fish, who swim around in enclosed pens, fed processed foods and medicines in an attempt to curb the constant threat of parasitic sea lice and diseases.

Despite this, a startling 9.5 million salmon--or a full 20%--die in these pens every year, the most common cause being illness: amoebic gill disease, salmon gill pox virus, proliferative gill disease, cardiomyopathy syndrome, pancreas disease, anaemia and fungus. In 2018, Marine Scotland, responsible for monitoring the welfare of farmed fish, visited Vacasay, a farm on Loch Roag, and rated parasite growth as 'satisfactory'. Inspection reports seen by the BBC, however, had showed significant lice damage to fish, so two weeks later, photographer Corin Smith went out for another look to film above and inside the pens and discovered a severe sea lice infestation.

'...what I saw was an incident of severe sea lice infestation, and the fish were being essentially eaten alive by the parasites. I couldn't believe what I was seeing, I couldn't believe the numbers and the damage.'[13]

When these photos became public, inspectors Marine Scotland returned within days. This time, they reported high levels of the parasite and four farms were sent warning letters. They claimed that sea lice grow quickly and boasted that the problem was already under control.[14]

This far from the only such instance; in June 2019, Don Staniford of Scottish Salmon Watch filmed in three farms in Loch Shieldaig. He filed a welfare complaint for what he saw, lice-infested cages with 'salmon gasping for air at the surface and covered in white lesions with visible damage to snouts, eyes, tails, fins and flanks...Such damage has occurred over a sustained period and has not just happened overnight – this is clearly as case of prolonged suffering and months of ongoing agony.' Upon seeing the footage, Compassion in World Farming backed his complaint; chief executive Philip Lymbery described himself as 'shocked anew', despite having worked on fish welfare issues for 30 years. '[This] reinforces my view that industrial salmon rearing is little more than factory farming at sea. Confined in vast numbers, these natural ocean wanderers have little choice but to swim in small circles liked caged tigers, all too often becoming diseased, riddled with parasites and wearing themselves sore in the process.”[15]

And the latest numbers are even worse: more than ten million fish died prematurely in 2019, higher than in any previous year but part of a larger pattern of increasing death rates in fish farms.[16] (The salmon fishing industry responded to this pattern, incidentally, by no longer reporting these numbers routinely as they had been, complaining that doing so was damaging their business.) 70% of these farms are certified 'RSPCA Assured', but their salmon standard advisory boards are staffed mainly by figures from the aquaculture industry itself--a clear conflict of interest. (Learn more about why 'RSPCA Assured' isn't all it's cracked up to be.)


All this disease and suffering affects more than just the caged salmon. Wild salmon, too, whose numbers continue to drop despite no longer being commercially fished, swim through the same waters as their caged counterparts. This decline is attributed in part to climate change, but fish farms are another culprit: as wild fish swim past and around them, they can pick up the infectious diseases and pathogens that kill so many farmed fish prematurely, as well as sea lice--and they do. In 2018, biologist Paul Hopper was alerted to an epidemic of dead and dying salmon making their way back to their spawning grounds in the Outer Hebrides. While wild fish always have 'background levels' of sea lice, Hopper explained, an epidemic like this in a wild population was 'really quite unusual'.[17] The dead fish were found close to several fish farms on Loch Roag.

It isn't just the fish who suffer: the seabed does too. David Ainsley is a marine biologist and a diver. By 2019 he had filmed the seabeds next to a Loch Shuna fish farm for eight years. Only fellow divers are aware of how bad the damage is, he reported: 'We found large areas of bacterial mat, we found lots of dead things on the seabed. In fact, there's very little left alive.' This should come as no surprise: fish farms use a great deal of chemicals and produce an enormous amount of food waste and faecal matter, all of which falls to the seabed below. According to marine ecologist Dr Sally Campbell, '...most people who choose salmon off their supermarket shelves have no idea of the waste that's going into our marine environment as a result of that. And they would be appalled.'[18]


In 2021, Animal Equality released footage from a salmon slaughterhouse operated by The Scottish Salmon Company, which supplies major UK supermarkets as well as many international retailers. Their investigation revealed fish clearly conscious and suffering after a failed stunning, being clubbed multiple times, having their gills torn and being thrown to the floor to suffocate, among many other abuses.[19] 

Mark Borthwick, Head of Research at the Aquatic Life Institute, was 'alarmed' by the footage, stating that 'A significant number of salmon are clearly conscious when their gills are cut, which could result in extreme pain for as long as seven minutes.'[20]



The fishing industry is the largest source of ocean plastics, littering the oceans with nets, fishing line and much more. In fact, 70% of the macroplastics in the ocean is fishing-related; a study of the Great Pacific Garbage Patch found that 86% of microplastics were from the fishing industry as well.[21] Macroplastics like nets and fishing line, known as 'ghost gear', entangle and kill an estimated 650,000 marine animals a year, many of whom are endangered----seabirds like albatrosses, whales and dolphins, sharks, sea turtles and more.[22] 

What's more, a full 40% of what the fish industry catches--and kills--is unintentional. These victims are known as bycatch, and as in the case of ghost gear, they are made up of multiple species, many of which are endangered. Up to 320,000 seabirds and at least 50 million sharks are killed as bycatch annually, for example, and sustainable seafood labels like 'Dolphin Safe' or 'Marine Stewardship Council' have proven to be unreliable.[23],[24],[25] In fact, when asked whether products labelled as 'dolphin safe' were guaranteed to have involved no dolphin deaths, Mark J Palmer of the Earth Island Institute (which manages the label) responded: 'Nope. Nobody can. Once you’re out there in the ocean, how do you know what they’re doing? We have observers on board but observers can be bribed and are not out on a regular basis.' [26]

Meanwhile, the United Nations FAO states that 87% of fish stocks are overexploited or fully exploited.[27]

The oceans have been the victims of a 'giant Ponzi scheme' thanks to the fishing industry, explains marine ecologist Daniel Pauly. In his landmark study, Fishing Down Marine Food Webs, Pauly found that the industry was responding globally to the decimation of larger species like cod by simply redirecting their fishing efforts further down the food chain.  Faulty record-keeping and poor science kept population counts local, and playing with the numbers a bit--simply removing certain species from counts once they were entirely depleted, for instance--helped further the deception. (For example, when the Hudson River sturgeon disappeared, it wasn't counted as having been overfished. It was simply removed from the equation entirely.)[28] It was only once the numbers were examined on a global basis that the devastating scale of the destruction was uncovered. 

The industry also renamed fish if their current names might make them less appealing to diners, and thus continued to fish down the food chain by targeting new species. One example of many is the Chilean Seabass, which was known as 'Patagonian Toothfish' until 1977. That's when an enterprising fish wholesaler, finding that populations of preferred species were no longer large enough to be profitable, decided to try to introduce the toothfish to the market.[29] (Incidentally, toothfish--or Chilean Seabass, if you like--are now at risk of extinction as a result of this successful marketing attempt.)


'...eating a tuna roll at a sushi restaurant should be considered no more environmentally benign than driving a Hummer or harpooning a manatee.'

Marine Ecologist Daniel Pauly



  1. Sulis Kim, Elizabeth, The anti-plastic straw campaign is helpful – but if we want to save marine life, we need to stop eating fish, 2018-9-2, The Independent

  2. Jabr, Ferris, It’s Official: Fish Feel Pain, 2018-1-8, Smithsonian Magazine

  3. Fish are Sentient,,uk, 2019

  4.  ibid.

  5. Yue, Stephanie, Ph.D, An HSUS Report: The Welfare of Farmed Fish at Slaughter

  6. Mood, Alison, Worse things happen at sea: the welfare of wild-caught fish,, 2010

  7.  Humane Slaughter,, 2019

  8. Bittman, Mark, Loving Fish, This Time With the Fish in Mind, 2009-6-9, The New York Times

  9. The Seafood Eater’s Latest Conundrum, 2009-6-9, The New York Times

  10. Guilford, Gwynn, The future is here: People are now eating more farmed fish than wild-caught fish, 2016-6-14,Quartz

  11. Pauly, Daniel, Aquacalypse Now, 2009-9-28, The New Republic

  12. Until the Seas Run Dry: Report, Changing Markets Foundation, 2019-4

  13. Adams, Lucy, Is there a problem with salmon farming?, 2019-5-28, BBC

  14. Edwards, Rob, ‘Sick’ salmon film prompts government probe into Scottish fish farm, 2019-6-13, The Ferret

  15. Adams, Lucy, Is there a problem with salmon farming?, 2019-5-28, BBC

  16. Edwards, Rob, Farmed salmon deaths from disease reach record high, 2020-7-13, The Ferret

  17. Adams, Lucy, Is there a problem with salmon farming?, 2019-5-28, BBC

  18. ibid.

  19. Webster, Ben, Waitrose salmon supplier Scottish Salmon Company ‘let fish die on the floor’, 2021-2-13, The Times

  20. INVESTIGATION: Fish Killed While Fully Conscious in Scottish Salmon Slaughterhouse, 2021-2-15, Animal Equality

  21. Laville, Sandra, Dumped fishing gear is biggest plastic polluter in ocean, finds report, 2019-11-6, The Guardian

  22. World Wildlife Fund, Bycatch: a sad topic

  23. McVeigh, Karen, Industrial fishing ushers the albatross closer to extinction, say researchers, 2019-1-31, The Guardian

  24. Animal Welfare Institute, Shark finning, 2020

  25. Sessa-Hawkins, Margaret, International Seafood certification scheme needs to step up action on bycatch, 2018-2-18, Birdlife International

  26. Gallagher, Sophie, Seaspiracy: The 7 biggest claims from the new documentary, 2021-3-30, The Independent

  27. FAO Fishing and Aquaculture Department, The State of World Fisheries and Aquaculture, 2012

  28. Pauly, Daniel, Aquacalypse Now, 2009-9-28, The New Republic

  29. The Invention of the Chilean Sea Bass,