Does it hurt?
A study into the pain experienced by prawns whose eye was sliced open and crushed or ligated found that both procedures caused prawns to become disoriented, flick their tail (an escape reflex) and rub the traumatised area — all behaviours associated with pain. The ablated prawns were also less likely to seek shelter following the procedure, which researchers believe to indicate a degree of stress amongst these animals. The study concluded that:
“These procedures are traumatic not only because of the surgical treatment or ligation but also due to the subsequent discomfort and hormonal changes.”
Scientist Dr Robert Elwood has also studied the way prawns react to negative stimulus and concluded that their behaviour was “consistent with the interpretation of pain experience.”
What’s more, studies have found that prawns and other crustaceans are able to see polarized light, which humans can’t. This superior vision helps them with navigating through water, seeing transparent or silvery prey, and avoiding predators. Destroying a prawn’s eye not only destroys the hormonal gland moderating their reproduction, but impacts their vision as well. In a crowded farm environment, impaired vision is likely to increase the stress on these animals.