A new study shows some fish are learning to swim faster in effort to evade trawler nets. A team from the University of Glasgow in Scotland simulated trawl fishing in schools of wild minnows with a laboratory-based experiment to determine if their behavior was part of an evolutionary process. The study demonstrates how some fish were frequently captured and other fish were never captured.
Study suggests minnows evolve to avoid capture
The study’s lead researcher, Dr. Shaun Killen, wrote in a paper on the observations: “What we were interested in, within a trawling scenario, was whether there was a variation among the fish in terms of how likely they were to be captured. We looked at what role individual physiology played in determining which fish were captured and which ones were not.”
The study demonstrates that the harvest of select species is one of the key factors in evolutionary changes. Older studies show a similar pattern suggesting hunting and fishing of species spark genetic changes in some animals. The team also considered possible physiological changes like swimming abilities or metabolic rate in some fish. Killen explained some of the minnows that successfully escaped the trawl nets exhibited signs of anaerobic abilities.
Fish populations mature faster
There is also evidence of fish populations maturing faster when living in bodies of water frequented by fishermen, possibly indicating an evolutionary response to them. Killen speculates, “Many other factors that need to be considered, but there is a reason why some fish were better swimmers than others. But what will the trade-off be?”
The study raises questions and concerns about whether the fishing industry impacts the environment.