Paper 7 Discussion

The text says that: “this population of fish live in a spring-fed stream with constant year-round temperatures and therefore inhabit a relatively stable environment where the need to rapidly respond to unpredictable and dynamic changes is reduced”. What do you think about this? How much did it actually affect the results of the experiment? Would you choose this population for your research?

6 thoughts on “Paper 7 Discussion

  1. This fish has a long breeding season, so stable environments could help them to carry more on the breeding process. Stable environments seem to maintain their constant baseline GC across time.
    In my case, I would prefer to use the same species population, but to predict possible stress, I would consider manipulating on physical parameters (increasing or decreasing temp., dissolved oxygen concentration, on that level that animal will show the real stress signal).

  2. Exposure to chronic stress can modify the baseline cortisol and the treshold as well, and I think that the variations would be more visible in a population from a more stressful habitat, because the frequent exposure to stressors would bring up the individual differences in coping.
    After this research I would do the experiments wit other populations of the same species as well from more stressful habitats and then compare the results to get a more complete image – this way we could learn more about the heritability and the plasticity of stress response as well. Oh, and I’d even do some paternal half-sibling breeding too. It would be a loooooooong project.

  3. I don’t know the location, but after heavy rain a stream can change drastically, and also predators and parasites can cause disturbances in the homeosthasis, even in calm small ponds.
    In 9-spined sticklebacks there are studies, that in a predator free, calm environment the population can change drastically, there are selection on the ability to adapt via phenotypic plasticity. among many other things. So given enough time, an isolated population can have different responses, and different ability to respond. But in the stickleback studies, they compared multiple populations from different sites.
    I would choose this population, just to see what happens, but later I would compare it to other populations’ physiology.

  4. I think it affected the results greatly, because they used a species that is used to a relatively “calm” environments so the fact that they found no relationship between GCs and reproductive status is understandable, becuase in such environments individuals do not meet with stressors a lot therefore the need to have an elevated baseline during different gestational statuses seems to be insufficient.
    I would not have used this population for the study, but rather one that lives in a more “unstable” environment, where the need for a fast and sufficient response to stressors is more adaptive.

  5. I think it affected the results greatly, because they used a species that is used to a relatively “calm” environments so the fact that they found no relationship between GCs and reproductive status is understandable, becuase in such environments individuals do not meet with stressors a lot therefore the need to have an elevated baseline during different gestational statuses seems to be insufficient.
    I would not have used this population for the study, but rather one that lives in a more “unstable” environment, where the need for a fast and sufficient response to stressors is more adaptive.

  6. They used this as an explanation for why the gestational state did not affect the GC levels. To know how much this affected the results, another study would have to be done, comparing populations from more variable environments to stable ones. The results from such a study would then determine whether this population is suitable for this research.

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