Brain test shows crabs process pain

Nov. 26 () –

Researchers from the University of Gothenburg have shown for the first time that painful stimuli reach the brain of sea crabs, further proof that crustaceans suffer pain.

EEG (electroencephalogram) type measurements show clear neuronal reactions in the brain of crustaceans during mechanical or chemical stimulation, according to this study, which is published in the journal Biology.

In the search for greater welfare of the animals that humans kill for food, researchers at the University of Gothenburg have chosen to focus on decapod crustaceans. This includes seafood delicacies such as prawns, lobsters, crabs and crayfish that we catch both wild and farmed. Shellfish is currently not covered by animal welfare legislation in the EU, but this could be about to change. For good reason, according to researchers.

“We need to find less painful ways to kill shellfish if we want to continue eating them. Because we now have scientific evidence that they experience and react to pain,” he says. in a statement Lynne Sneddon, zoophysiologist at the University of Gothenburg.

Several research groups have previously carried out a series of observational studies on crustaceans, which have been subjected to mechanical impacts, electrical shocks or acids on soft tissues such as antennae. These crustaceans have reacted by touching the exposed area or trying to avoid the danger in repeated experiments, which has led researchers to assume that they feel pain.

Researchers at the University of Gothenburg are the first to conduct neurobiological studies by measuring activity in the brain of a common sea crab (carcinus maenas), through an EEG-style measurement.

“We could see that the crab has some kind of pain receptors in its soft tissues, because we recorded an increase in brain activity when we applied a potentially painful chemical, a form of vinegar, to the soft tissues of the crab. The same thing happened when we applied external pressure to various parts of the crab’s body,” says Eleftherios Kasiouras, a doctoral student at the University of Gothenburg and lead author of the study.

In the crab, the activity of the central nervous system of the brain was measured when the soft tissues of the claws, antennae and legs were subjected to some type of stress. The answers show that shore crabs must have some type of pain signaling to the brain from these parts of the body. The response to pain was shorter and more powerful in the case of physical stress than in the case of chemical stresswhich lasted longer.

“It is a fact that all animals need some type of pain system to cope with danger, thus avoiding danger. I do not think it is necessary to carry out tests on all species of crustaceans, since they have a similar structure and, therefore, Therefore, similar nervous systems We can assume that shrimp, crayfish and lobsters do too. can send external signals about painful stimuli to your brain, that will process this information,” says Kasiouras.

Researchers say we need to find more humane ways to handle and even kill crustaceans. Today, it is allowed to cut a live crustacean, unlike the mammals we eat.

“We need more research to find less painful ways to kill shellfish,” says Sneddon.