Do oysters feel pain?

Marine biologist Helen Scales took this on...

Helen - It's a great question and something that stirs up seafood lovers a lot. You've got your oyster there; you're shucking it away, adding a squeeze of lemon juice, and they say you should see the oyster twitching if you put lemon juice on it; this shows they can sense chemicals and they can sense things going on.

Do they feel pain? Great question. I think the answer has to be probably not, but we don't really know.

Oysters have a nervous system; they can respond. They have no brain as such; they have two ganglia - or masses of nerves - around their body, but not a central brain like ours.

I don't think anyone can possibly claim that oysters are conscious, that they have awareness like higher mammals (not just ourselves but other creatures like dolphins and things).

I certainly think there shouldn't be a big problem with oysters.

There's still debate going on about far more advanced creatures, like fish. Is it cruel to go fishing for fun? Do they feel pain? That's the sort of thing where the debate goes on.

Scientists have found a lot of very sensitive receptors in the faces of fish that we think probably mean they can detect damage to their skin. But whether that's actually translated into pain is the big question we haven't go to the bottom of yet.

Is it pain as we feel pain because they go 'ouch.' Or is it, 'I know that's going on: that's something that's not good and I need to do something about it,' But not necessarily, 'That really hurts.'

There was one study that does sound rather cruel but we do need to understand these things so they did it. They took freshwater trout (this is scientists from the University of Edinburgh) and they actually injected bee venom into their lips to see what that did.

What they found was that these fish, compared to ones that just had water injected into their lips, rubbed their lips on the bottom of their tank and on the gravel. They didn't go back to feed as quickly as the ones that just had water and they rocked.

In zoos sometimes or in older zoos when they weren't designed to keep animals to keep them interested and stimulated they could develop a rocking motion to show that they're not enjoying themselves. A similar thing is happening with these fish. Something is going on and I think they can sense pain.

It's still a question we haven't answered.