FISH can be CREATURES of HABIT, TOO
With such an obvious and wide range of differences, what could you or I think we could even possibly have in common with a fish? We breath through different mediums, we travel different paths, live in completely different ecological systems. However different our surroundings may be, fish and people may have more in common psychologically than we have ever thought before. Senior researcher at DTU Aqua Erik Höglund, one of Denmark's leading experts on fish behaviour and fish neuroscience, put out a statement saying fish can be divided into two personality types, proactive and reactive, just like people. Proactive fish were observed to be more aggressive and assertive, while also being more fixed in their ways. Reactive fish were more timid, but also looked to be able to adapt more easily to change.
Two strains of rainbow trout were bred at DTU Aqua in Hirtshals. One line was bred with proactive qualities in mind and the other with reactivity in mind. Each individual fish was contained in their own identical aquaria. Both strains of fish showed similarities in how quickly they initially learned how to find food, however, as the experiment progressed and the locations of the food began to change, the two strains began to show stark contrast. While reactive fish found and ate their food in only 46 seconds on average, it took proactive fish a much longer time of 976 seconds.The reactive fish would span their area in search of the food, while the proactive fish would go straight to where they were used to finding food, sometimes even swimming right over where the new location of the food was. Differentiating even further in their behavior, when a rubber barrier was placed into the aquariums, the reactive fish would attempt to hide from it, while the proactive fish would pay it no attention.
This experiment has showed researchers that not all fish are the same, and conditions for individual fish should be met in hopes of optimizing their commercial value. Further research has shown that fish with these different personalities will react differently when the oxygen content in the water declines, and DTU Aqua is working of a way for fish to communicate what their preferential oxygen density is. DTU Aqua has also demonstrated that fish have the same neurotransmitter that is found in humans' reactions to stress and fear. When the question of whether fish feel pain or not comes up, researchers confirm that physiologically, they possess the same receptors as humans, yet their experience may vary due to their level of consciousness.
The primary results show that reactive fish are more flexible, while proactive fish are more likely to adopt and follow specific routines. These findings and the others aforementioned have sparked an interest in fish behavior that Erik Hoglund believes is due to ethical concerns. Animal welfare plays a big part in the development of fish farming worldwide and as more fish are being used for drug experimentation, this new field of research in fish behavior will provide facts that can be utilized in future decision-making.
Posted by Chelsea Van Thof (6)
I think there may have been a similar post last week about fish personalities? Regardless, I think it is an interesting study to look at the different fish personalities because I don't think many people really think too much about fish. It would be impossible to tell just from a glance that a fish had a certain personality type. Is there any reasoning behind the type of personality a fish developes? When they did this experiment on the rainbow trout, how did they know that one would be reactive and one would be proactive? Also, do you think there are any benefits in the wild of either trait?
ReplyDeletePosted by Caitlin Descovich O'Hare
Hm, fish with different personalities. It seems more like behavior patterns that are genetically passed down than actual 'personalities.' Based on the information you provided, I don't see how being a proactive fish can be more benficial, although the only examples given are in locating food and interacting with an unknown object. Perhaps the proactive fish are better at territory defense and mating? Maybe this will have to remain open-ended if laws and restrictions on animal testing in fish increases. Still, the part about humans and fish having the same neurotransmitters for pain is interesting.
ReplyDeletePosted by Austin Gray
In Response to Caitlin O'Hare,
ReplyDeleteWow, you are right. Reading the posts from last week, I completely missed that this subject had already been explored. After reading that post now, I can see that I expanded more on the other experiments that were done around fish personalities, such as the ones having to do with their stress hormone and pain receptors. I also explained more how all of these experiments are beneficial to fish welfare.
You are also right to say that people do not think as much about fish, relative to other animals, as they should. Fish and commercial fisheries are a hugely important part of the economy and our diets, and we do not do enough in the research field to try to understand them properly.
I think the reason behind the type of personality a fish develops is for natural selection, ultimately. I think more proactive are naturally selected for, because they can better adapt to new living environments with different food resources. I think that is also the benefit of being a proactive fish in the wild, where your living environment can become unpredictable at any moment- that proactive fish is more likely to survive in such a case. I assume that when they decided to do this experiment, they were basing their hypotheses on past research, and that is how they may have known that fish have a tendency to be either proactive or reactive.
Posted by Chelsea Van Thof
This is very interesting. Do you know if these behaviors are genetic and passed down? Could they be influenced by the environment they are in and also do you think they interact differently with their siblings rather than their neighbors just like some plant species? It is pretty cool to think that animals other than humans posses this personality quality about them.
ReplyDeletePosted by Ryan Dulmaine