Crustaceans (including crayfish, lobsters, crabs, and prawns), are invertebrate animals with hard exoskeletons.

Studies show that crayfish, lobsters, crabs, and prawns have complex social interactions and the ability to recognise individuals.

Lobsters can live for over 100 years, but are commonly captured and killed at just 5-7 years of age. 

Globally, billions of crustaceans are captured, farmed, and killed for human consumption every year.

The RSPCA states, "Crustaceans show responses consistent with signs of pain and distress​. They also have the cognitive capacity to remember and learn to avoid unpleasant stimuli."

Despite scientific evidence that crustaceans experience and respond to pain and distress, these sentient beings endure processes that would be considered torture if done to other animals.

The most common methods for killing crustaceans around the world, particularly for commercial purposes, include:

Boiling alive

"Spiking" for crabs, where the worker uses a pointed spike to "rapidly destruct both nerve centres by piercing both ganglia from the underside of the crab".

"Splitting" for lobsters, where the worker uses a knife to "rapidly cut through the centre-line of the head, thorax (chest) and abdomen to destroy the nerve centres". 

Spiking and splitting are both inherently difficult to perform accurately and can easily result in the crab or lobster remaining conscious, and thus feeling the pain of being boiled alive.

Sometimes stunning is used prior, which can include chilling, electrical stunning, or carbon dioxide gassing. These stunning methods can cause extreme pain. 

The RSPCA says "It is possible that chilling in dry air or in ice is painful and, once chilled, that it does not render the crustacean insensible to further pain from spiking, splitting, or cooking."

Ineffective stunning is commonplace, resulting in many crustaceans remaining fully or partially conscious, enduring the pain and stress of both ineffective stunning, and being boiled alive. 

There are welfare concerns associated with all stunning and killing methods. 

Crustaceans are also commonly dismembered (a process in which workers cut or tear parts of the crustacean's body off) while conscious, causing unimaginable agony. A common form of dismemberment is tailing (separation of the abdomen from the thorax, or separation of the head from the thorax). 

According to invertebrate zoologist Jaren G. Horsley, Ph.D., "The lobster does not have an autonomic nervous system that puts [them] into a state of shock when [they are] harmed. They probably feel themselves being cut. ... I think the lobster is in a great deal of pain from being cut open ... [and] feels all the pain until [their] nervous system is destroyed [during cooking/boiling alive]." 

Dr. Horsley also states, "As an invertebrate zoologist who has studied crustaceans for a number of years, I can tell you the lobster has a rather sophisticated nervous system that, among other things, allows [them] to sense actions that will cause [them] harm. ... [Lobsters] can, I am sure, sense pain." 

The stress behaviours observed in crabs and lobsters include trying to escape, thrashing, and autotomy. Autotomy is a behavioural response in which animals shed their own limbs or other body parts, in response to damage, capture, or to stop the spread of potentially harmful stimuli to the rest of their body. 

Legal protection status

The legal protection of crustaceans varies between states and countries.

Crustaceans are invertebrates, and South Australia, Queensland, Tasmania, and Western Australia do not consider invertebrates as animals, meaning that in these states, crustaceans have no legal protection at all. 

In the ACT, New South Wales, Victoria, and the Northern Territory, the definition of "animal" includes crustaceans "in particular circumstances". 

The UK government commissioned the London School of Economics and Political Science (LSE) to conduct a comprehensive review of over 300 scientific studies, reviewing the evidence of sentience in two groups of invertebrate animals: cephalopod molluscs (including octopods, squid, and cuttlefish), and decapod crustaceans (including crabs, lobsters, prawns, and crayfish). 

The LSE reported that all cephalopod molluscs and decapod crustaceans are sentient animals, defining sentience as the capacity to have feelings such as pain, distress, harm, suffering,  pleasure, hunger, thirst, warmth, joy, comfort, and excitement. 

As a result of this comprehensive review of over 300 scientific studies, in 2021, the UK government extended the scope of the Animal Welfare (Sentience) Bill to recognise all decapod crustaceans and cephalopod molluscs as sentient beings.

The LSE recommended a ban on boiling alive, slowly raising the temperature of water, tailing and any other form of live dismemberment, and freshwater immersion (osmotic shock), due to the pain, distress, and suffering the animals feel during.  

While the UK government's decision could be considered a positive step, it does not affect any existing legislation or industry practice, meaning that all of the above practices that the LSE recommended banning are still legal, and countless lobsters, crabs, prawns, and crayfish in the UK are still in pain and suffering, being boiled alive, and being subject to numerous other horrifically painful procedures. Even if made illegal, this would likely still be the case due to difficulty with enforcement, especially in non-commercial settings.