Brown Trout Have Personality

Canadian (December 16, 2010) We know that it is hard to believe it, but scientists believe that fish are showing personality traits. No, they can’t talk or communicate yet, but researchers at the University of Gothenburg have found that brown trout have individual characters and show different personalities. Over the years, Bart Adriaenssens (Zoology-University of Gothenburg) has studied juvenile trout in the rivers and streams along the west coast of Sweden. He stated that “My results show that it are not just humans and other mammals that exhibit personality. Also brown trout differ among each other in their level of aggression and react differently to changes in their surroundings. The release of a novel object in the aquarium causes very different reactions. Some individuals will immediately explore this object, whereas others will rather hide in a corner and try to avoid every contact.”
“But it are not always the bold and aggressive fish who are most successful. When we marked trout individually and released them back in the wild, it were shy trout who grew most rapidly.”
The fish’s personality may work well in one environment, but not another. In a tank such as an aquaculture facility, the aggressive fish will get more food and grow larger and faster than the shy fish. However, in the wild where its habitat is much more complex, the shy individuals will be more successful.
Bart Adriaenssens also stated that “If a certain personality proves to work well, and individuals with that personality grow rapidly, survive in greater numbers and have more offspring, we would expect all individuals to behave according to that personality. This is not the case, however, and there is still a lot of work to be done in this area to explain why,”
This has raised some interesting questions that we do not agree completely with. We believe that over the short term that this would not have an effect, but over the long term (many generations), it would.
What do you think and why?
Wayne Sheridan