Life and Death of a Decapod

by Shona Spray

When it comes to the subject of animal welfare and protection, there are many animals and causes which first come to mind. Most of you might immediately think of your pet cats and dogs, which hold a special place in our hearts and could never imagine another human harming them. Second might be cows, pigs and sheep, animals we view as cute, intelligent, sentient beings worth protecting from stress and pain. 

There is one group of animals, however, which is often overlooked and suffers silently. These animals are not stereotypically thought of as cute and cuddly, but they are no less deserving of our protection and respect. These animals are currently being provided little to no protection by our government and are continuously exploited and treated with extreme cruelty and zero regard to their health or wellbeing (4).

Decapods, a class of crustaceans including lobster, crabs, prawns and shrimp, have become a staple in the British diet, with some crustaceans, particularly the lobster, being labelled a “delicacy”(2,3,9). Large numbers of crustaceans are caught by creel fishers or grown by aquaculture to meet demand(7,8). Seafood in general is a food source that many take for granted due to its abundance, especially on a small island like Britain surrounded by a fishable ocean(8). 

Global consumption of crustaceans has increased, with the number of individuals killed each year estimated to be in the billions(3). In 2023, it was calculated that the number of shrimp and prawns killed each year could even be in the high trillions(4). As a result, crustaceans continue to be mistreated in ways which could, and should, be labelled as torturous.

Compared to livestock raised in the UK, such as cows, chickens, pigs, and even fish, crustaceans have little to no protection with regard to their welfare(4). With no legislation in place to protect crustaceans from commonplace practices, which can only be described as cruel, these animals are treated in ways which would be illegal if they were carried out on any cattle, sheep or chicken farm(4).

Historically, crustaceans have been treated this way due to the presumption that they were unable to feel pain, suffering or experience negative emotions such as stress(1,3). However, multiple studies have presented overwhelming evidence to suggest that this is not the case(2,3). 

The criteria for determining whether an animal can experience pain are generally when they show behaviours that help prevent future harm, allowing time to heal and recover after an encounter with a pain-inducing event(1,5). These behaviours include the avoidance of anything which has previously caused pain, bodily reactions, defensive actions, and an indication that pain is alleviated when treated with painkillers(1,2).

One such study conducted by Patterson et al. (2007) investigated the experience of pain and stress in crustaceans and found that de-clawing live crabs caused the crabs to exhibit a stress response, which was measured by increased lactate levels, and could be seen in both short (1-10 minutes) and long (24 hours) time periods(1,3,4). It was also noted that the rate of deaths increased with the size of the wound after claw removal, suggesting that the more severe the injury, the higher the number of deaths(1,4).

Other studies have obtained similar results, and parallels can be drawn between the behaviour of mammals and crustaceans in response to painful stimuli(1,5). When mammals encounter something painful, they often rub, lick or groom the area which is in pain(1). Similarly, Glass prawns, upon having one antenna exposed to acetic acid, exhibited a significant increase in the grooming and rubbing of the affected antenna(1,3). This behaviour was not as extreme if the antenna had been treated with a local anaesthetic beforehand(1).

Studies with both crayfish and hermit crabs showed that upon being subjected to electric shock, both species displayed prolonged signs of anxiety(1,3). Hermit crabs even left their shells to avoid the area(1,3,4). Again, these avoidance behaviours were reduced if they were prescribed a drug which reduces anxiety in humans(1,3).

Not only does the previously described evidence strongly suggest that crustaceans experience pain and stress, but a review of the brain structure of decapods by Crump et al. (2022) determined that decapod brains are complex enough to facilitate complex behaviours and possess a lot of the elements to make pain a possibility(4).

Yet crustaceans continue to be widely mistreated, with farmers and restaurant workers using commonplace and barbaric practices(5). Crustaceans, which are produced for the food industry, have no respite from the pain and stress they endure, all the way from the fisheries where they are hatched to the restaurants where they die

In some fisheries, crabs will have their claws pulled or twisted from their bodies whilst the crab is still alive and conscious(3,4). Their bodies are then thrown back into the sea, where they will most likely die without the use of their legs(4). Lobsters also have to endure this process, but unfortunately, do not have the luxury of being thrown back to the sea afterwards, but are impaled on a spike so that the tail meat can be taken, all whilst still alive(3,4). It takes several minutes for the lobsters to die(3,4).

In aquaculture systems, prawns have their eyestalks removed to encourage egg production(4,5). Transport can take days, and live crustaceans are often kept in tanks with their claws bound with zip-lock ties and/or mutilated to prevent them from being used in defence(4). Upon slaughter, the most common practices include being chilled in a freezer before being boiled alive and carbon dioxide gassing, which suffocates the animals, if, that is, the animals have not died from extreme stress and pain before then(2,3,5).

In 2022, a bill on the sentience and welfare of animals (Animal Welfare (Sentience) Act (2022)) was put in place to aid the protection of animals by recognising that animals are sentient beings who feel and should be valued and protected(5,6). While invertebrates (animals without backbones) were not originally included in the first draft, the final draft officially recognises decapods to be sentient beings(4,6,7).

This act would suggest that change would be imminent and drastic, considering the conditions many crustaceans currently experience(4,7). However, despite this definitive law, no legislation is currently in place in the United Kingdom to specifically provide decapods more protection(4).

It has only been in the last decade that animal welfare organisations have recognised that this is an important problem that needs to be tackled(4). Since 2013, People for the Ethical Treatment of Animals (PETA), has been standing against the dismembering and mutilation of live lobsters and crabs and has been urging the public to avoid eating them in restaurants in protest of these practices(4). 

The UK-based foundation, Crustacean Compassion, was founded in 2016 specifically to tackle the need for change and to improve the welfare of decapods, and played a big part in making sure decapods were included in the Animal Welfare (Sentience) Act (2022)(4). While these organisations are doing great work educating people on this topic and campaigning for the rights of crustaceans, I believe that we still have a long way to go before any permanent change can be made. 

Sources

[1] Carder, G., (2017) A preliminary investigation into the welfare of lobsters in the UK. Animal Sentience, 16(19), pp.1-9. https://www.wellbeingintlstudiesrepository.org/cgi/viewcontent.cgi?article=1262&context=animsent 

[2] Yue, S., (2008). The Welfare of Crustaceans at Slaughter. Agribusiness Reports, 2008(5), pp. 1-10. https://www.wellbeingintlstudiesrepository.org/cgi/viewcontent.cgi?article=1011&context=agreports 

[3] Conte, F., Voslarova, E., Vecerek, V., Elwood, R. W., Coluccio, P., Pugliese, M., and Passantino, A. (2021). Humane Slaughter of Edible Decapod Crustaceans. Animals, 11(4), p. 1089. https://doi.org/10.3390/ani11041089.

[4] Elwood, R. W., (2025). A History of Pain Studies and Changing Attitudes to the Welfare of Crustaceans. Animals, 15(3), p. 445. https://doi.org/10.3390/ani15030445.

[5] Birch, J., Burn, C., Schnell, A., Browning, H. and Crump, A. (2021). Review of the evidence of sentience in cephalopod molluscs and decapod crustaceans. The London School of Economics and Political Science. Available at: https://www.lse.ac.uk/News/News-Assets/PDFs/2021/Sentience-in-Cephalopod-Molluscs-and-Decapod-Crustaceans-Final-Report-November-2021.pdf. 

[6] Lobsters, octopus and crabs recognised as sentient beings. Gov.uk. Available at https://www.gov.uk/government/news/lobsters-octopus-and-crabs-recognised-as-sentient-beings 

Open Government License https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ 

[7] Wuertz, S., Bierbach, D., and Bögner, M., (2023). Welfare of decapod crustaceans with special emphasis on stress physiology. Aquaculture Research, 2023(1), pp. 1-17. https://doi.org/10.1155/2023/1307684.

[8] Harrison, L.O., Engelhard, G.H., Thurstan, R.H., and Sturrock, A.M., (2023). Widening mismatch between UK seafood production and consumer demand: a 120-year perspective. Reviews in Fish Biology and Fisheries, 33(4), pp. 1387-1408. https://link.springer.com/article/10.1007/s11160-023-09776-5 

[9] Freire-Paz, E., (2023). Galician shellfish: sustenance in poverty and a delicacy in affluence. International Journal of Gastronomy and Food Science, 31, p.100654. https://doi.org/10.1016/j.ijgfs.2022.100654 

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