Preface
Briefing description and more.
This briefing catalogs the breadth and severity of the suffering and injustices fish undergo at the hands of humans and also provide slaughter counts.
Share this Briefing
Social Media Sharing Image
This image will be used when sharing the briefing on a social media platform. You can see all social sharing images in the grid view.
How to share this briefing
Click on the icon for the platform on which you wish to share. What happens next depends on the platform, but generally a popup will appear, letting you add your own text as you share.
Briefing Meta
Metrics
Note: We will publish additional briefings after completing flashcards for all briefings and presentation slides for all core briefings.
Counts:
| Main Text | |
| Key Injustices | 8 |
| Supplementary | 3 |
| Further Study | 5 |
| Footnotes | 34 |
| Media & Advocacy | |
| Advocacy Notes | 11 |
| —Socratic Questions | 17 |
Other Meta:
Date Posted:
Last Edited:
Edit Log:
Help Us Improve
Please send your suggestions for improvements, or report any issues with this briefing to team@vbriefings.org
We appreciate that you are taking the time to help up improve. All suggestions and reports will be carefully considered.
Summary
A concise summary of the briefing (see below for citations).
Fish are sentient beings capable of suffering, yet they endure systemic injustices in both commercial and farmed fishing industries. Commercially caught fish suffer through suffocation, crushing, decompression injuries, and slow freezing, while farmed fish face stress from overcrowding, poor water quality, disease, and painful slaughter methods that often fail to ensure unconsciousness. Globally, over a trillion fish are caught annually, and billions more are farmed under conditions that cause physical injuries, genetic issues, and prolonged suffering. Despite their vast numbers and capacity for pain, fish are commodified and exploited without regard for their inherent worth as individuals.
Context
Places this topic in its larger context.
The injustices inherent in exploiting non-human animals stem from seeing them as commodities having only instrumental value, lacking any inherent worth apart from their usefulness to humans.
Key Injustices
This section provides talking points.
Methods of Slaughter: Commercially Caught Fish
Suffocation
Rather than being slaughtered, wild-caught fish are often left to suffocate to death after being hauled onto the fishing boat.1
Crushing and Circulatory Failure
When huge numbers of fish are caught in trawl nets, those at the bottom are inevitably crushed to death.2
Decompression
Fish who are caught at depths of 20 meters or more may suffer decompression injuries when rapidly pulled to the surface causing…
- their internal organs to be forced out of their mouths or anuses (prolapse)
- their eyes to be pushed out of their sockets
- their swim bladders to burst3
Freezing
Any fish who survive being caught and pulled to the surface may still be alive when they are put into freezers on the fishing boat, leaving them to freeze to death slowly.4
Methods of Slaughter: Farmed Fish
Asphyxiation
The most common method of killing farmed fish is asphyxiation, either in air or ice slurry.
Fish placed in ice slurry usually only struggle briefly before becoming immobile, but they can respire for up to 50 minutes.
Fishes can show signs of life for several hours when left to asphyxiate in air.5
Bleeding, beheading, or gutting alive
Some species of fish are bled out to improve the flavor of their flesh.
Bleeding out is often done while the fish is still alive.
Fish may have their heads cut off or be eviscerated without first being stunned.
Fishes’ brains can continue to function for some time even after decapitation.6
Percussive stunning
Percussive stunning (a blow to the head) does not always lead to immediate unconsciousness.7
Fish can continue to be conscious after percussive stunning because of improper technique:
- holding the fish in the wrong position
- stunning them in the wrong location
- not using enough force8
Percussive stunning is not suitable for many types of fish because of.
- their size
- the shape of their skulls9
Electrical stunning
Electrical stunning may be carried out either in or out of the water (known as wet or dry stunning).
Electrical stunning does not always lead to immediate unconsciousness. Complications involve:
- the wrong voltage10
- inadequate contact with stunning paddles (dry stunning on conveyor belts)11
- the conductivity of the water12
Carbon dioxide
Salmon are often killed by being placed in water infused with carbon dioxide.
Carbon dioxide poisoning is slow and has been banned in Norway because it is inhumane.13
Spiking
Some fish are killed by driving a tool into the brain to destroy it.
One study that analyzed the accuracy in spiking found that the tool misses the brain up to 50% of the time, causing a slow, painful death.14
Other Methods of Fish Slaughter.
Since they are difficult to kill, eels are often killed with cruel methods such as immersion in an ammonia solution, a salt bath, or gutting them alive.
Tuna may be shot in the head while still in the water.
Carp are often sold alive and killed by buyers at home. They are likely to be kept out of water for long periods and are likely to be killed poorly without proper equipment.15
Living Conditions: Farmed Fish
Farmed fish experience several stresses because of their living conditions. Examples:1617
Overcrowding may cause:
- stress
- loss of scales
- lack of oxygen
- possible gill damage
- heart problems (possibly due to insufficient exercise)
Poor water quality can occur because of the amount of feces produced in crowded conditions.
Disease and parasites:
- are rife because of overcrowding, causing irritation and discomfort.
- include sea lice, which can eat the flesh of farmed fish, causing lesions and even exposure of the skull in severe cases.
Health issues are common, including:
- skeletal problems
- cataracts
- soft tissue malformations
Abrasion may occur when fish come into contact with the cage walls.
Transportation can cause stress and increased mortality.
Cannibalism is an unnatural behavior that may occur if large and small fish are kept together.
Rough Handling:
- may cause injury to fish, potentially leading to infection.
- when removed from the water, may result in suffering due to a lack of oxygen and even death because of stress.
Artificial light:
- is used to manipulate fish’s growth and reproduction.
- may cause stress.
Predation:
- occurs when fish are kept in pens or cages in natural bodies of water.
- occurs when animals like seabirds, seals, and otters injure or prey on the fish, who cannot easily escape because they are confined.
Denial of natural behaviors is inevitable on fish farms. Fish who would swim several kilometers a day in the wild are kept confined in small cages where they cannot exercise natural behaviors such as feeding and migration.
Selective Breeding and Reproduction
Genetic Engineering
Genetic engineering of salmon to grow faster has caused:
- enlargement of the head.
- an impaired immune system.
- breathing difficulties.18
Triploidy
Triploidy is a genetic manipulation that renders salmon sterile, prevents farmed fish from breeding with wild ones, improves meat quality, and makes fish grow larger.
Triploidy causes:
- cataracts.
- spinal deformities.19
Hormone Injection
Hormone injection is necessary for some species to allow them to spawn when kept in artificial conditions.
Injected hormones are often obtained by slaughtering other carp to remove their pituitary glands.20
Slaughter for Breeding
Some species are slaughtered so that they can be cut open and their eggs or sperm removed to be used for breeding.21
Treatment and Handling
Hooking
Fish have a similar pain system to mammals and birds, and their mouths contain many sensory receptor cells.
Hooking is painful and stressful and can also lead to entrapped fish being attacked by predators if not reeled in immediately.
In longline fishing, fish may be hooked for hours or even days until the lines are retrieved.22
Forced Fasting
Farmed fish may be deprived of food for several days before slaughter, potentially depressing the immune system and causing hunger.23
Transport and Packing
Crowding
Crowding is the use of a net to encircle all fish in the enclosure prior to transport. The lack of oxygen caused by crowding can cause injury, stress, and even death in some cases.
Pumping
Pumping sucks the fish and water through the tube for a distance ranging from a few meters to over a kilometer, sometimes causing injury by projections or sharp edges in the pipe, or by colliding with one another.24
Brailing
Brailing involves transporting fish in a net called a brail, some of which can hold several hundred kilograms.25
Dry Brailing
With dry brailing the fish come into contact with the net, each other, and other surfaces, causing crushing, bruising, abrasion, and puncture injuries.26
Wet Brailing
Wet brailing, in which fish are submerged, reduces the risk of harm, but fish sometimes fall onto each other or onto a hard surface, causing injury.27
Live Bait
Live fish are often used as bait to catch larger fish, resulting in confinement for days or weeks.
Baitfish are often impaled live on hooks and eaten alive by predators, unable to escape.
Catch and Release
Some recreational anglers prefer to throw fish back into the water alive after catching them.
Hooking is painful—the mouths of fish contain pain receptors.28
Hooks of catch and release fish sometimes puncture the throat or internal organs, causing death in anywhere from 3 percent to 86 percent depending on the species and the type of hook and bait used.29
Counterclaims
Responses to some yes but retorts.
No counterclaims are addressed in this briefing.
Supplementary Info
Additional information that may prove useful.
Globally, over one trillion fish are caught each year, and over 50 billion are farmed.
Global fish counts30
- Caught Fish: .79-2.3 trillion
- Farmed Fish: 51-167 billion
Note: It is difficult to say how many fish are pulled from the oceans each year, as the catch is measured by weight rather than the number of individuals.
In the United States, over 6 billion fish are caught each year, and over 200 million are farmed.
United States fish counts31
- Caught Fish: 6.29-13.51 billion
- Farmed Fish: 244-583 million
Of the over 34,000 species of fish, only a few are used for food.
Further Study
Sources providing a deeper understanding of the topic or related topics.
Advocacy Resources
Information to help with outreach and advocacy.
Note: We will publish additional briefings after completing flashcards for all briefings and presentation slides for all core briefings.
Share this Briefing
Social Media Sharing Image
This image will be used when sharing the briefing on a social media platform. You can see all social sharing images in the grid view.
How to share this briefing
Click on the icon for the platform on which you wish to share. What happens next depends on the platform, but generally a popup will appear, letting you add your own text as you share.
Socratic Questions (17)
Socratic-style questions are embedded in the Advocacy Notes below, and shown in italics.
These are open-ended, thought-provoking questions designed to encourage critical thinking, self-reflection, and deeper understanding. They are inspired by the Socratic method, a teaching technique attributed to the ancient Greek philosopher Socrates, who would ask his students probing questions rather than directly providing answers.
The goal is to help people examine their beliefs, clarify their thoughts, uncover assumptions, and explore the evidence and reasoning behind their ideas.
Advocacy Notes (11)
Tips for Advocacy and Outreach
General Tips
Many people do not consider fish in their ethical thinking. Your goal is to challenge assumptions, expose the brutality of the fishing industry, and make people rethink their perception of fish as mere commodities.
Reframe the conversation. The issue isn’t just how fish are killed—it’s whether we have the right to kill them at all.
Have Them Acknowledge That Fish Suffer
People often assume fish do not feel pain or experience suffering. Shift the focus to their ability to experience harm.
- “If fish do not feel pain, why do they struggle desperately to escape hooks, nets, and handling?”
- “Why do fish show stress responses when injured, just like land animals do?”
Why? This forces them to recognize fish as sentient beings rather than objects.
Expose the Reality of Commercial Fishing Slaughter
Wild-caught fish experience prolonged and agonizing deaths, yet most people never think about how they are killed.
- “What does it say about an industry when suffocation, crushing, and bleeding out while fully conscious are the standard methods of slaughter?”
- “If fish are pulled from deep water so fast that their internal organs rupture due to pressure changes, can we really say they are killed humanely?”
Why? This reveals how violent and painful commercial fishing is for fish.
Show That Farmed Fish Suffer in Overcrowded, Polluted Conditions
Many assume that farmed fish have better lives than wild-caught fish, but they endure horrific conditions.
- “How do fish benefit from farming when they are packed so tightly that they suffer from deformities, infections, and oxygen deprivation?”
- “If disease and parasites are rampant in fish farms, often eating fish alive, how can the industry claim this is humane?”
Why? This exposes the myth that fish farming is a humane alternative to commercial fishing.
Challenge the Notion That Fish Slaughter Is Humane
Fish are killed in some of the most brutal ways imaginable, often remaining conscious for long periods.
- “Would we accept any other animal being clubbed repeatedly or left to asphyxiate as a humane method of killing?”
Why? This makes them question whether fish slaughter is ever ethical.
Expose the Brutality of Recreational Fishing
Many people see catch-and-release fishing as harmless, but it inflicts serious pain and injury on fish.
- “How can fishing be just a ‘harmless sport’ when the hook pierces a fish’s face, rips their tissue, and leaves them vulnerable to infection?”
- “What happens to fish thrown back into the water with torn mouths and internal injuries—how many of them actually survive?”
Why? This forces them to reconsider the ethics of sport fishing.
Reveal the Suffering Behind Live Bait and Other Cruel Practices
Live bait and other ignored aspects of the fishing industry cause immense suffering.
- “How can impaling live fish on hooks or cutting them into pieces while they are still conscious be considered humane?”
- “If baitfish are kept in confinement and then discarded like trash, do their lives matter any less?”
Why? This highlights an overlooked aspect of fish cruelty.
Expose How Fish Are Treated as Disposable Commodities
Because fish are killed in such high numbers, their suffering is dismissed.
- “When billions of fish are discarded as ‘bycatch’—thrown back into the ocean to die—what does that say about how little their lives are valued?”
- “If fish were counted as individuals rather than by weight, would people think differently about how many are killed?”
Why? This makes them see fish slaughter as a mass atrocity.
Challenge the Notion That Fish Matter Less Than Land Animals
Some people dismiss fish suffering because they are different from mammals. Help them rethink this bias.
- “Why should the ability to blink or vocalize determine whether an animal’s suffering matters?”
- “If fish could make sounds like cows or pigs when they were killed, do you think more people would care?”
Why? This challenges the idea that fish are less worthy of moral concern.
Leave Them With a Thought-Provoking Question
If they resist, don’t argue—leave them with something to consider.
- “If an industry kills billions of animals every year using methods that cause extreme suffering, is there any way to justify supporting it?”
- “When so much of the fishing and aquaculture industry involves suffering, is there any ethical way to consume fish?”
Why? A strong question stays with them long after the conversation ends.
Footnotes
Our sources, with links back to where they are used.
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- .Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Gregory, Neville G., and Temple Grandin. Animal Welfare and Meat Science. Oxon, UK ; New York, NY, USA: CABI Pub, 1998. 209-10. ↩︎
- Stevenson, Peter, Compassion in World Farming (Organization), and World Society for the Protection of Animals. Closed Waters: The Welfare of Farmed Atlantic Salmon, Rainbow Trout, Atlantic Cod and Atlantic Halibut. Godalming, Surrey: Compassion in World Farming, 2007. ↩︎
- Mood, A, and P Brooke. “Estimating the Number of Farmed Fish Killed in Global Aquaculture Each Year,” July 2012. ↩︎
- Stevenson, Peter, Compassion in World Farming (Organization), and World Society for the Protection of Animals. Closed Waters: The Welfare of Farmed Atlantic Salmon, Rainbow Trout, Atlantic Cod and Atlantic Halibut. Godalming, Surrey: Compassion in World Farming, 2007. ↩︎
- “FAO Fisheries & Aquaculture Hypophthalmichthys Molitrix.” ↩︎
- Rottman, RW, JV Shireman, and FA Chapman. “Techniques for Taking and Fertilizing the Spawn of Fish.” Southern Regional Aquaculture Center, November 1991. ↩︎
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Lines, J.A., and J. Spence. “Humane Harvesting and Slaughter of Farmed Fish: -EN- Humane Harvesting and Slaughter of Farmed Fish -FR- Le Respect Du Bien-Être Des Poissons Lors Des Prises et Des Opérations d’abattage -ES- Recolección y Sacrificio Incruentos de Peces de Cultivo.” Revue Scientifique et Technique de l’OIE 33, no. 1 (April 1, 2014): 255–64. ↩︎
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Mood, Alison. “Worse Things Happen at Sea: The Welfare of Wild-Caught Fish.” fishcount.org.uk, 2010. ↩︎
- Estimates are from United Nations FAO data compiled by Fishcount UK. Fish Count UK: “Estimated Numbers of Individuals in Annual Global Capture Tonnage (FAO) of Fish Species (2007 – 2016)“. ↩︎
- Estimates are from United Nations FAO data compiled by Fishcount UK. “Estimated numbers of individuals in aquaculture production (FAO) of fish species (2017).” ↩︎
- Fish Base version 02 2022 ↩︎
- Kapoor, B. G., and Bhavna Khanna, eds. Ichthyology Handbook. Berlin: Springer, 2004. 1. ↩︎
- Kapoor, B. G., and Bhavna Khanna, eds. Ichthyology Handbook. Berlin: Springer, 2004. 1. ↩︎
