Euthanasia Of Freshwater Fish

[LauraFrog]

This is again opinion and I worry that I'm letting too much of it into the scientific section, but I also believe it's a valid argument and belongs in this topic.

There is no way to know for certain whether or not fish feel pain. You can't just go and hack off half a fish's fin and then ask it whether that hurt. So wouldn't it be right, for the sake of the general care, medical treatment and/or euthanasia of tropical fish, to ASSUME that they feel pain, because the consequences of getting it wrong are sort of like Pascal's Wager?

I mean, if you assume that fish feel pain, treat them as though they feel pain, and do your best to prevent them from being in pain, and you are wrong and fish do not feel pain, you have not lost anything. If, on the other hand, you assume fish don't feel pain and you are wrong, then you may have caused a large amount of suffering. So if the evidence is even either way and you can't come to a definite conclusion on whether or not fish feel pain, in my opinion it would make sense to be 'on the safe side' and assume that they do feel pain in order to prevent pain if they can experience it.

 

[andywg]

This is again opinion and I worry that I'm letting too much of it into the scientific section, but I also believe it's a valid argument and belongs in this topic.

You are not basing your opinion in science though.

Scientists have conducted scans of the brain when a human is feeling pain and have identified the area of the brain which deals with pain (I cannot recall the exact area but I believe it is the Anterior cingulate cortex). The area of the brain which deals with pain in mammals is not present in fish meaning that they do not have the requisite biological means to process pain in the way that mammals do; hence the opinion that the fish do not feel pain, much like someone missing the area of the brain that makes you want to sleep will not feel drowsy.

Thus, the belief that fish do not feel pain is not based on an assumption, but on observations.

If you can prove that fish do feel pain (perhaps by processing it in a completely different way from what has been shown) then I believe the sport of fishing may have some problems.

 

[LauraFrog]

Okay, here is some (considerably more scientific) evidence that I came across recently. I can quote the direct source if you want me to... one of my teachers apparently did a fairly advanced thesis on the topic of fish feeling pain.

They took some fairly big fish, I believe they were gropers. They injected an irritant into the lower lip of the test group and a saline solution (same quantity, same location) into the control group. The fish in the control group behaved normally. The fish in the test group scraped their lips along the substrate, refused food, and were generally agitated. They bashed their lips on objects and behaved as though distressed.

Then they took half the fish that they had injected the irritant into and injected morphine. These fish behaved normally. The untreated fish continued to act as if they were in some distress.



Also, it has been proven by radical epilepsy surgery that it is possible to remove an entire hemisphere of somebody's brain and still have them function relatively normally. Studies of people who have had strokes, tumours and brain surgery abound, and many demonstrate that it IS possible for other parts of the brain to take over the function of areas that have been removed or damaged. I see no reason why the absence of the parts of the brain that process pain in mammals means that there is not another part of the fish brain that can process pain. At any rate, for the purposes of 'rather safe than sorry' I will continue to treat fish as though they do experience pain until it is conclusively proven otherwise - because the debate's still out.

 

[andywg]

Okay, here is some (considerably more scientific) evidence that I came across recently. I can quote the direct source if you want me to... one of my teachers apparently did a fairly advanced thesis on the topic of fish feeling pain.

They took some fairly big fish, I believe they were gropers. They injected an irritant into the lower lip of the test group and a saline solution (same quantity, same location) into the control group. The fish in the control group behaved normally. The fish in the test group scraped their lips along the substrate, refused food, and were generally agitated. They bashed their lips on objects and behaved as though distressed.

Then they took half the fish that they had injected the irritant into and injected morphine. These fish behaved normally. The untreated fish continued to act as if they were in some distress.

However, one must be careful not to confuse nociception (the reaction to an adverse stimulus) with pain (the psychological treatment of such signals within the brain). The research you are talking about is that carried out by Dr Sneddon and was discussed at posts 6, 13, 23 and 24 of this very thread.

Also, it has been proven by radical epilepsy surgery that it is possible to remove an entire hemisphere of somebody's brain and still have them function relatively normally. Studies of people who have had strokes, tumours and brain surgery abound, and many demonstrate that it IS possible for other parts of the brain to take over the function of areas that have been removed or damaged. I see no reason why the absence of the parts of the brain that process pain in mammals means that there is not another part of the fish brain that can process pain.

However we are not talking about people being able to develop doing something that the brain was never designed to do. For example, we do not have an ability to process electrical signals received through a lateral line system. Therefore, though it might be possible for other areas of a fish's brain to take over the interpretation of these signals we have never had the capability to do so and as such your anthropomorphisation with regards to studies on the human brain (which is regarded as one of the most developed) would not seem to be the best of

At any rate, for the purposes of 'rather safe than sorry' I will continue to treat fish as though they do experience pain until it is conclusively proven otherwise - because the debate's still out.

That is your choice, however it is not entirely relevant to a discussion on the science of whether a fish feels pain or not.

 

[mike os]

However, one must be careful not to confuse nociception (the reaction to an adverse stimulus) with pain (the psychological treatment of such signals within the brain). The research you are talking about is that carried out by Dr Sneddon and was discussed at posts 6, 13, 23 and 24 of this very thread.



Personally I am not convinced the two are separable except as words, i.e. prove that humans experience "pain" rather than "nociception" described in "non scientific" terms. ie that "pain" is simply "nociception expressed in words".

 

[andywg]

Personally I am not convinced the two are separable except as words, i.e. prove that humans experience "pain" rather than "nociception" described in "non scientific" terms. ie that "pain" is simply "nociception expressed in words".

Wiki is quite well resourced on this:

"For scientific and clinical purposes, pain is defined by the International Association for the Study of Pain (IASP) as 'an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage'."

This often quoted definition was first published in 1979 by IASP in Pain journal, number 6, page 250. It is derived from a definition of pain given earlier by Harold Merskey: "An unpleasant experience that we primarily associate with tissue damage or describe in terms of tissue damage or both." Merskey, H. (1964), An Investigation of Pain in Psychological Illness, DM Thesis, Oxford.

In The Kyoto protocol of IASP Basic Pain Terminology by Loeser JD, Treede RD. (2008) Pain 137 (3) nociception is described as "the neural processes of encoding and processing noxious stimuli"

One should avoid using pain and nociception as synonyms. The International Association for the Study of Pain states "Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause"


So, basically, nociception is the unconscious workings of the body whilst pain is the mental suffering often associated with injury. How often do you not notice how much a cut hurts until you see it, or that you have already moved your hand away from the iron by the time you notice you have burned yourself? That is the best way I can find in more lay terms for the difference between pain and nociception.

 

[Schmill]

So based on this, (and please excuse if I am wrong, as I am a beginner to all this );

If the fish were injected with an irritant that caused a physical reaction, that is not neccasarily pain, (it could be sub-conscious reaction).
However if this irritant was then 'removed', and you were to then later approach the fish with the same needle/syringe that was recognisable (by the fish) as the irritant, and the fish made an effort to avoid the reapplication of said irritant, would that constitute 'pain', as it is then a conscious mental reaction by the fish to avoid the 'feeling' that the irritant provided last time it was applied?

 

[Schmill]

<double post>

 

[mike os]

Personally I am not convinced the two are separable except as words, i.e. prove that humans experience "pain" rather than "nociception" described in "non scientific" terms. ie that "pain" is simply "nociception expressed in words".

Wiki is quite well resourced on this:

"For scientific and clinical purposes, pain is defined by the International Association for the Study of Pain (IASP) as 'an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage'."

This often quoted definition was first published in 1979 by IASP in Pain journal, number 6, page 250. It is derived from a definition of pain given earlier by Harold Merskey: "An unpleasant experience that we primarily associate with tissue damage or describe in terms of tissue damage or both." Merskey, H. (1964), An Investigation of Pain in Psychological Illness, DM Thesis, Oxford.

In The Kyoto protocol of IASP Basic Pain Terminology by Loeser JD, Treede RD. (2008) Pain 137 (3) nociception is described as "the neural processes of encoding and processing noxious stimuli"

One should avoid using pain and nociception as synonyms. The International Association for the Study of Pain states "Activity induced in the nociceptor and nociceptive pathways by a noxious stimulus is not pain, which is always a psychological state, even though we may well appreciate that pain most often has a proximate physical cause"


So, basically, nociception is the unconscious workings of the body whilst pain is the mental suffering often associated with injury. How often do you not notice how much a cut hurts until you see it, or that you have already moved your hand away from the iron by the time you notice you have burned yourself? That is the best way I can find in more lay terms for the difference between pain and nociception.

I would not trust wiki to give me the time of day LOL.....


ergo "pain" in the sense of this discussion is a myth..... an individual psychological response to a specific stimuli or situation, not a "special" or "advanced " area of the brain or a specially developed response in an "advanced animal".

Pain in this sense is a "learned response" or a "perception" rather than a reality then, nociception is the actual "pain response", otherwise injury=pain irregardless of the observation.

 

[andywg]

I would not trust wiki to give me the time of day LOL.....

Then, to put it bluntly, you are ignorant of a very good source of information. When wiki provides links to scientific journals which can be checked it is just as reliable as any source. Wiki provides a fantastic first point of call to then show where to get peer reviewed information.

ergo "pain" in the sense of this discussion is a myth..... an individual psychological response to a specific stimuli or situation, not a "special" or "advanced " area of the brain or a specially developed response in an "advanced animal".

It is a personal psychological treatment of a stimulus which is handled in mammals in an area of the brain which is not present in fish; that is scans of people who state they are experiencing pain shows areas of the brain working that have not developed in fish.

 

[mike os]

i would agree with wiki being good for links, but then so is google, a lot of the info there is very poor.

 

[andywg]

i would agree with wiki being good for links, but then so is google, a lot of the info there is very poor.

So poor it was found to be as accurate as the Encyclopaedia Britannica in a comparison

 

[Bignose]

I would not trust wiki to give me the time of day LOL.....

It doesn't matter if it comes from wikipedia, fishlopedia, the Flat Earth Society, or your Great Aunt Maggie -- if the citations are solid, then it should be respected. To dismiss something out of hand just because it is stored on a certain person's or group's server or webpage is just ridiculous.

Judge each work on it's own merit and it's own citations.

 

[LauraFrog]

I don't know whether this is anything more than 'brain droppings', but it *might* be relevant:

Firstly, why do we assume that just because a certain part of the brain has a certain function in a mammal, it must have the same function in a fish? I would be very interested in some accurate studies of the working of the fish brain (ie is sensory information from the eyes processed in the same location as in the mammalian brain?)

Also, has anybody considered species differences? I would suggest it's very likely that a mouse experiences pain very differently to the way a human experiences pain, the latter being far more intelligent. There is no doubt to my mind that there is a notable difference in intelligence between, say, a guppy and a large cichlid. So if fish can experience pain, is it possible that the more intelligent of the fishes would experience it more intensely or suffer more?

If you touch a hot iron, as andywg said, you automatically jerk your hand away before you have time to consciously register pain. BUT it is very likely you will then hop around on the spot clutching your burned hand and swearing loudly. The unconscious movement of your hand from an unpleasant stimulus is nociception. The jumping around is because you are in pain. Is there any evidence of this in fish?

Also, for the purposes of this thread is there any difference between discomfort and pain? I am sure that fish are aware of discomfort when their water is the wrong temperature, too salty, contains ammonia, or when their tank is too small, etc. If you dig your thumb very hard into my arm, it's not painful and you aren't actually causing tissue damage. But it's uncomfortable and I'd want you to stop. Don't fish deserve this consideration as well?

 

[mike os]

I would not trust wiki to give me the time of day LOL.....

It doesn't matter if it comes from wikipedia, fishlopedia, the Flat Earth Society, or your Great Aunt Maggie -- if the citations are solid, then it should be respected. To dismiss something out of hand just because it is stored on a certain person's or group's server or webpage is just ridiculous.

Judge each work on it's own merit and it's own citations.

how about when it is just plain incorrect then? events that i have been part of factually deficient or politically biased? Some of the info is good, some bad, ergo it cannot be trusted, especially when you are not already reasonably knowledgeable in a particular subject. The base problem is unfortunately also one of it's potential strengths, public editing, especially by those who really do not know enough about the subject or who have their own agenda