In a study that appeared in the Proceedings of the Royal Society B journal, researchers have studied the common features of fish that make them the most likely victims of trawling, reported BBC News.
"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," stuy lead author Shaun Killen, from the University of Glasgow, told BBC News.
The study revealed that fish that were less able to produce fast burst-type swimming to prevent being captured were more likely to end in the nets. The findings of the study could help explain how fishery has brought about certain evolutionary changes in fish populations.
As part of the study, the team carried out simulated trawl fishing on schools of wild minnows (Phoxinus phoxinus).
Writing in their paper, Dr Killen and colleagues observed: "Selective harvest of animals by humans probably represents one of the strongest drivers of evolutionary change for wild animals."
When the team found that there were some fish that were consistently captured by trawling and there were some that were never captured, they considered the question whether this was related to any aspect of the physiology of the fish.
"The fish that were most able to escape a simulated trawl where the ones where really good anaerobic athletes," Dr Killen told BBC News. "If you think about Olympic athletes, sprinters will be the ones that have a really good anaerobic capacity whereas the long-distance runners will be more aerobic.
"We found that the ones that were capable of really fast bursts of movement were the ones most able to avoid capture."
Dr. Killen also revealed that the available body of information indicates that the populations of fish that are exposed to fishing seem to mature earlier and are also smaller in size.
However, he added, "there is a big question as to whether or not that is an evolutionary effect of fishing pressure".
