Vulnerability to Fishing Predicted by Fish Personalities

Written by on November 10, 2014 in Fish, Marine Life

A few weeks ago, we learned that sharks have individual social personalities that influence how they interact with each other. Now, new research shows fish personalities reflect how vulnerable an individual is to fishing.

Brown trout. Photo credit: via photopin cc.

Brown trout. Photo credit: via photopin cc.

The study completed at the University of Eastern Finland and the Finnish Game and Fisheries Research Institute revealed that individual differences in “moving activity” are linked to differences in angling vulnerability. Using long-term observations of individual behavior of brown trout (Salmo trutta) in groups, the researchers found that fishing modifies the behavioral traits that are passed down to the next generation by favoring more cautious fish.

The researchers found that “exploratory behavior” was closely linked to fishing vulnerability in experimental, semi-natural stream environments. So, the more willing the trout were to explore new environments, the more vulnerable they were to fishing. The researchers also note that body size or differences in swimming activity were not linked to fishing vulnerability.

The study aimed to determine whether the vulnerability of fish raised in a hatchery could be predicted by “rearing method” (standard or enriched) or by behavioral variations. In enriched environments, the ponds had shelter, and water levels, current speeds and feeding times changed at irregular intervals. In standard environments, everything, including feeding time, was regulated. The brown trout reared in enriched environments were less likely to explore than those raised in standard hatcheries. Standard-rearing resulted in fish that were more vulnerable to fishing.

These findings could have major implications for successful stock management if hatchery-raised fish are released in an attempt to boost wild populations.

Brown trout. Image credit: NOAA.

Brown trout. Image credit: NOAA.

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Copyright © 2014 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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