Do SHELLfish feel pain?

Written by on January 17, 2013 in Fish, Marine Life

We knew it couldn’t be the end of the “do fish feel pain” debate…

New research reveals that crabs, previously known to respond to pain, may actually feel it.

Common shore crab (Carcinus maenas).

Common shore crab (Carcinus maenas). Photo credit: Hans Hillewaert.

Professor Bob Elwood and Barry Magee from Queen’s School of Biological Sciences subjected common shore crabs to small electrical shocks and monitored their response and their behavior after the shock.

“The experiment was carefully designed to distinguish between pain and a reflex phenomenon known as nociception,” said Professor Elwood. “The function of pain is to aid future avoidance of the pain source, whereas nociception enables a reflex response that provides immediate protection but no awareness or changes to long-term behavior.

“While nociception is generally accepted to exist in virtually all animals the same is not true of pain. In particular, whether or not crustaceans experience pain remains widely debated.”

Note: This is what we wrote about earlier in the week–fish respond to pain because they have nociceptors, but the most recent study found that this is only a reflex and they do not actually feel any pain.

The crabs in this experiment were given a tank with two dark shelters. Crabs value these dark “hideaways” because they can hide from predators. After “two rounds of shocks, the crabs learned to avoid the shelter where they received the shock. They were willing to give up their hideaway in order to avoid the source of their probable pain,” Professor Elwood said.

He notes that this research should be considered in the food industry.

“Billions of crustacean are caught or reared in aquaculture for the food industry. In contrast to mammals, crustaceans are given little or no protection as the presumption is that they cannot experience pain. Our research suggests otherwise.”

“On a philosophical point it is impossible to demonstrate absolutely that an animal experiences pain. However, various criteria have been suggested regarding what we would expect if pain were to be experienced. The research at Queen’s has tested those criteria and the data is consistent with the idea of pain. Thus, we conclude that there is a strong probability of pain and the need to consider the welfare of these animals.”

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Copyright © 2013 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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