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Thread: No need to fear the pheromones (!?)

  1. #11
    Jumbo jnorth's Avatar
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    Quote Originally Posted by RobF View Post
    Among koi keepers it is the general believed that pheromones are a bad thing. But just what bad thing is it that the pheromones supposed to be doing? Communicating to other koi not to grow? Here is a study, the effect of various pheromone categories are assessed for goldfish and carp. Pheromones may provide information about alarm, about congregation, about reproductive timing, but growth is not on the list of things under pheromone influence. Given otherwise good water quality there is just a much reason to imagine that koi prefer a pheromone filled environment (it smells friendly!) to an austere one (anybody home?)! http://carpbusters.com/documents/Sorensen_Stacey[1].2004.NZJfinal.pdf
    I've heard that before and quite frankly could care less about pheromones. I do water changes because I know from experience that I if I don't then the koi on average will not grow as well as if I do. Besides aren't pheromones something that love potions are made out of?
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  2. #12
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by ricshaw View Post
    Back to my question Mike, why do some Koi exhibit stunted growth and others don't in the same exact environment?

    If some Koi do not exhibit impeded growth to persistent exposure to pheromones/hormones from nitrate and other metabolites... that leaves "genetics" as an explanation.
    First, I'd distinguish between 'stunted' and 'small'. Some koi will not grow beyond a certain size due to genetics. All but one of my koi over 6 years of age exceed 80cm. The exception is around 65cm. I have had her from tosai and know she was not subjected to poor conditions at any point in her life. She is a quality koi, but was sold off as tosai because she was part of a group in her spawning that lagged in growth. She does not have a big fish bone structure. Younger fish have passed her by in growth. I've considered moving her on, but she took an award at a show and has wonderful pigment, so she stays. That's genetics. She just isn't going to grow larger.

    I do not have any stunted koi. I do have stunted guppies... guppies that I know have the genetics to grow much larger, but got stuck at a small size. There are a number of factors that coincide with stunting in guppies. First and foremost is feeding during the first 4 weeks of life. A batch given limited food will become stunted. Another batch from the same brood given baby brine shrimp and a variety of dry feeds multiple times during the day will become comparatively huge. (In the 1960s, these were called 'giant guppies'. They were just well-fed guppies with genetic potential.) Feeding every 45 minutes with extremely high protein food optimizes ultimate adult size. Curiously, the well-fed ones are sometimes slower to mature than those given limited rations. A close second is crowding. In a crowded tank they mature prematurely and cease growth, even if the amount of food fed is the same on a per fish basis and water changes are performed more frequently. Third is water quality. As contaminant levels build, growth slows. (I use nitrate as a marker for all contaminants. DOC could be used also.) Fourth, temperature is a major factor. Cool water, even if fully within an acceptable range, results in smaller fish than warm water at the upper end of the preferred range. Fifth, a calm environment is a factor. If there is a lot of vibration, sudden bumps, etc., they do not grow as well. They will tend to hide and skip food. Feeding increases when they feel safe and secure. Disease/parasite exposure in the early weeks of life does not seem to cause stunting, but, of course, that only applies to survivors.

    Now, guppies are not koi. There are some similarities in that male guppies cease growth upon reaching sexual maturity, while female guppies continue to grow, albeit slowly. Unlike koi, a year-old guppy is an old fish. Very few guppies reach two years of age.

    My take from keeping numerous generations of guppies is that something gets in the water that causes stunting if they are crowded or if water changes are not kept up. It is generally said that it is hormones/phermones. I do not know a scientific basis for such statements. I've never searched for scientific studies on the subject. Whatever it is that causes the stunting, I know the stunting occurs.

  3. #13
    Honmei ricshaw's Avatar
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    Quote Originally Posted by MikeM View Post
    First, I'd distinguish between 'stunted' and 'small'. Some koi will not grow beyond a certain size due to genetics. All but one of my koi over 6 years of age exceed 80cm. The exception is around 65cm. I have had her from tosai and know she was not subjected to poor conditions at any point in her life. She is a quality koi, but was sold off as tosai because she was part of a group in her spawning that lagged in growth. She does not have a big fish bone structure. Younger fish have passed her by in growth. I've considered moving her on, but she took an award at a show and has wonderful pigment, so she stays. That's genetics. She just isn't going to grow larger.
    People who show Koi, buy better quality Koi, and tend to get rid of Koi that do not meet their high expectations.

    On the other hand many Koi club members, who buy lesser quality Koi, tend to keep their "pets" even if they start to exhibit 'stunted' body conformation.

    I keep some lesser quality Koi too long. I have Koi that are between 6 - 33 years old that are less than 80 cm (65 cm - 70 cm being the norm). I have one that is 84 cm.

  4. #14
    Daihonmei MikeM's Avatar
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    Quote Originally Posted by ricshaw View Post

    I keep some lesser quality Koi too long.
    It's too long only if you do not enjoy them.

  5. #15
    Daihonmei MikeM's Avatar
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    I'm bringing up this thread because I came across references to a study of direct interest. I have not gotten access to the full study report, so I'm assuming the following is an accurate summary.

    Perimutter, Alfred, Daniel Sarot, Man-Lin Yu, Rocco Filazzoia and Seely, Effects of Crowding on the Immune Response of Fish.

    This study indicates that there are hidden factors at work that are not readily visible or apparent to most koi keepers. Sometimes we simply notice that our koi die without explanation. Perhaps the study by Perimutter et al can throw some light on this phenomenon. Their study may indicate that fish kept in overcrowded conditions suffer impaired immune systems as a result of biochemical agents released into the water by the other fish living in the pond. This may be natures way of reducing a large population to more acceptable levels. The studies suggest that fish can release immune suppressing pheromones (hormones) in overcrowded conditions. This make the other fish in the system less able to fight disease.

    To investigate their suspicions, three separate experiments were set up. These involved different treatment and control groups. The first two experiments had 30, 15, 5 and 5 fish respectively. Four similar control groups were set up. Fish were assigned randomly among the groups. All ponds were the same size. The water in the treatment groups had methylchloroform added to remove organic substances. The control groups were not treated but simply monitored. Ammonia, nitrate, dissolved oxygen, carbon dioxide and pH were monitored regularly.

    The immune systems were challenged with infectious Pancreatic necrosis virus. All fish in the treatment and control groups were injected with the virus two weeks after the experiment began. Two week later they were injected again. The researchers made antibody tests. These antibody measurements showed that maximum antibody reaction occurred three weeks after the second injection of the virus. Fish from the experimental groups had two to four times the antibody levels compared to the fish from the control groups. As the level of crowding increased so the difference between the groups increased. The implication was that the methylchloroform was removing something from the water that affected the fish immune response.

    This unknown factor was directly proportional to the crowding level. The greater the crowding level the greater the immune suppressing effect. The evidence suggested an immune suppressing pheromone was present.

    To check their findings the authors then decided to refine a third experiment. This third experiment was run twice with each of the four treatment and control groups. These being 30, 15, 5 and 5 fish again. The results were as follows:

    1. The groups of fish at low stocking densities had twice the antibody level of the control groups.

    2. The groups with slightly higher stocking densities had four times the antibodies present.

    3. As stocking densities increased the effect of the immune suppressing agent became more pronounced. There were less and less antibodies recorded in the test groups.

    4. It is worth noting that even at low stocking densities there was a lower antibody count. This indicates that even at low stocking densities there is immune response suppression.

    Conclusions: Low stocking densities can help minimize bacterial and viral disease problems. It is presumed that the fewer the fish in the water the less the concentration of pheromone present that suppress the immune system. The lower the stocking density the lower the bacterial load on the pond. The offending pheromone can be removed with proper chemical and physical techniques.

  6. #16
    Daihonmei MikeM's Avatar
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    The summary of the study refers to pheromones. But, I am not aware of any method for determining whether pheromones or hormones are the causative factor. Chemicals released by an organism to 'communicate' externally with other organisms are labeled as 'pheromones'; and chemicals released to 'communicate' internally with organs/body parts are labeled as 'hormones'. [Chemicals emitted by organisms to 'communicate' with other species get labeled as allomones, kairomones, synomones and elsewise when they 'communicate' with other species either for the benefit of the emitter, the benefit of the receiver or mutual benefit.] There are all sorts of chemicals emitted by living creatures. We humans have a need to categorize these chemicals to study them, but I'd not get hung-up on whether pheromones or hormones are involved in affecting the immune system. It is enough to know that some chemical or combination of chemicals has an immune suppressant impact.

    From that tidbit of 'fact', it is not difficult to assume there are many other impacts... including on growth, maturation and development in general. Aquatic creatures are heavy users of chemical communication tools. Perhaps it is because water is a friendlier medium than drying air. Whatever the reason, there are numerous chemicals released by aquatic creatures. In open water, no doubt many would have negligible or no effect beyond a small area in close proximity to the emitting creature. In our closed ponds, it is a very different world.

    While the study indicates that the substances can be neutralized with methylchloroform, I certainly would not recommend use of such chemicals. Rather, it is the old dull, boring rant… perform large, frequent, regular water changes; or, a continual flow-through system. Dilution is the solution. If water shortages limit water use, consider a foam fractionator as a way to reduce DOC (which includes pheromones/hormones) and thereby allow somewhat less water use.

  7. #17
    Jumbo Appliance Guy's Avatar
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    Quote Originally Posted by MikeM View Post
    I'm bringing up this thread because I came across references to a study of direct interest. I have not gotten access to the full study report, so I'm assuming the following is an accurate summary.

    Perimutter, Alfred, Daniel Sarot, Man-Lin Yu, Rocco Filazzoia and Seely, Effects of Crowding on the Immune Response of Fish.

    This study indicates that there are hidden factors at work that are not readily visible or apparent to most koi keepers. Sometimes we simply notice that our koi die without explanation. Perhaps the study by Perimutter et al can throw some light on this phenomenon. Their study may indicate that fish kept in overcrowded conditions suffer impaired immune systems as a result of biochemical agents released into the water by the other fish living in the pond. This may be natures way of reducing a large population to more acceptable levels. The studies suggest that fish can release immune suppressing pheromones (hormones) in overcrowded conditions. This make the other fish in the system less able to fight disease.

    To investigate their suspicions, three separate experiments were set up. These involved different treatment and control groups. The first two experiments had 30, 15, 5 and 5 fish respectively. Four similar control groups were set up. Fish were assigned randomly among the groups. All ponds were the same size. The water in the treatment groups had methylchloroform added to remove organic substances. The control groups were not treated but simply monitored. Ammonia, nitrate, dissolved oxygen, carbon dioxide and pH were monitored regularly.

    The immune systems were challenged with infectious Pancreatic necrosis virus. All fish in the treatment and control groups were injected with the virus two weeks after the experiment began. Two week later they were injected again. The researchers made antibody tests. These antibody measurements showed that maximum antibody reaction occurred three weeks after the second injection of the virus. Fish from the experimental groups had two to four times the antibody levels compared to the fish from the control groups. As the level of crowding increased so the difference between the groups increased. The implication was that the methylchloroform was removing something from the water that affected the fish immune response.

    This unknown factor was directly proportional to the crowding level. The greater the crowding level the greater the immune suppressing effect. The evidence suggested an immune suppressing pheromone was present.

    To check their findings the authors then decided to refine a third experiment. This third experiment was run twice with each of the four treatment and control groups. These being 30, 15, 5 and 5 fish again. The results were as follows:

    1. The groups of fish at low stocking densities had twice the antibody level of the control groups.

    2. The groups with slightly higher stocking densities had four times the antibodies present.

    3. As stocking densities increased the effect of the immune suppressing agent became more pronounced. There were less and less antibodies recorded in the test groups.

    4. It is worth noting that even at low stocking densities there was a lower antibody count. This indicates that even at low stocking densities there is immune response suppression.

    Conclusions: Low stocking densities can help minimize bacterial and viral disease problems. It is presumed that the fewer the fish in the water the less the concentration of pheromone present that suppress the immune system. The lower the stocking density the lower the bacterial load on the pond. The offending pheromone can be removed with proper chemical and physical techniques.
    While the names sound foreign, the US government must have had a role in this. Why else would there be a study for what every basic fish keeper knows....

    Out of curiousity, Mike, what fish was used as subjects?

  8. #18
    Honmei ricshaw's Avatar
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    How do you know where this study was conducted?

  9. #19
    Daihonmei MikeM's Avatar
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    I have not found the study in a publication. I've only found the information I quoted. So, I cannot add anything about the study.

  10. #20
    Oyagoi yerrag's Avatar
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    Quote Originally Posted by MikeM View Post
    I'm bringing up this thread because I came across references to a study of direct interest. I have not gotten access to the full study report, so I'm assuming the following is an accurate summary.

    Perimutter, Alfred, Daniel Sarot, Man-Lin Yu, Rocco Filazzoia and Seely, Effects of Crowding on the Immune Response of Fish.

    This study indicates that there are hidden factors at work that are not readily visible or apparent to most koi keepers. Sometimes we simply notice that our koi die without explanation. Perhaps the study by Perimutter et al can throw some light on this phenomenon. Their study may indicate that fish kept in overcrowded conditions suffer impaired immune systems as a result of biochemical agents released into the water by the other fish living in the pond. This may be natures way of reducing a large population to more acceptable levels. The studies suggest that fish can release immune suppressing pheromones (hormones) in overcrowded conditions. This make the other fish in the system less able to fight disease.

    To investigate their suspicions, three separate experiments were set up. These involved different treatment and control groups. The first two experiments had 30, 15, 5 and 5 fish respectively. Four similar control groups were set up. Fish were assigned randomly among the groups. All ponds were the same size. The water in the treatment groups had methylchloroform added to remove organic substances. The control groups were not treated but simply monitored. Ammonia, nitrate, dissolved oxygen, carbon dioxide and pH were monitored regularly.

    The immune systems were challenged with infectious Pancreatic necrosis virus. All fish in the treatment and control groups were injected with the virus two weeks after the experiment began. Two week later they were injected again. The researchers made antibody tests. These antibody measurements showed that maximum antibody reaction occurred three weeks after the second injection of the virus. Fish from the experimental groups had two to four times the antibody levels compared to the fish from the control groups. As the level of crowding increased so the difference between the groups increased. The implication was that the methylchloroform was removing something from the water that affected the fish immune response.

    This unknown factor was directly proportional to the crowding level. The greater the crowding level the greater the immune suppressing effect. The evidence suggested an immune suppressing pheromone was present.

    To check their findings the authors then decided to refine a third experiment. This third experiment was run twice with each of the four treatment and control groups. These being 30, 15, 5 and 5 fish again. The results were as follows:

    1. The groups of fish at low stocking densities had twice the antibody level of the control groups.

    2. The groups with slightly higher stocking densities had four times the antibodies present.

    3. As stocking densities increased the effect of the immune suppressing agent became more pronounced. There were less and less antibodies recorded in the test groups.

    4. It is worth noting that even at low stocking densities there was a lower antibody count. This indicates that even at low stocking densities there is immune response suppression.

    Conclusions: Low stocking densities can help minimize bacterial and viral disease problems. It is presumed that the fewer the fish in the water the less the concentration of pheromone present that suppress the immune system. The lower the stocking density the lower the bacterial load on the pond. The offending pheromone can be removed with proper chemical and physical techniques.
    This is interesting. How can offending pheromones me removed with chemical and physical techniques? Would help to know as an alternative to frequent water changes. The Cali drought makes this question more relevant.

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