Intense fishing compels fish to learn faster swimming to stay safe from the trawler netsMd Noman Siddique (Author) Published Date : Aug 06, 2015 22:58 IST
Based on experiments in the laboratory researchers have noted the common characteristics of fish that most vulnerable to be caught by the trawler nets. They noticed that fish that could not use the burst type swimming were more likely to end up in the trawlers nets. The data obtained is expected to be helpful in finding answers to questions about evolutionary change in different species of fish that were induced by fisheries.
Lead author of the study, Shaun Killen from University of Glasgow explains that the researchers were interested in examining the likelihood of the fish being captured and the variation among different varieties of fish in a trawling scenario. The researchers also examined the individual physiology that determined the fishes that were captured and the ones that escaped the trawler nets. Dr. Killen and colleagues noted that selective harvest by humans possibly represented one of the strongest drivers for evolutionary changes in wild animals. They added that according to previous studies, there was a suggestion that fishing and hunting could trigger genetic changes within various wild populations. In experiments conducted within the laboratory environments, the team simulated trawl fishing on schools of fish. They noticed significant variation and they were repeatable also. There were certain types of fish that were captured consistently by the trawlers while there were also some that either gave the slip always or were never targeted.
The next question that came up was whether there was a relationship between the physiology of the fish like their swimming or metabolic rate. It was noticed in simulated environments that fish which exhibited excellent anaerobic athletic qualities almost always escaped the nets.
If we turn our thoughts to the Olympic athletes, sprinters exhibit a good anaerobic ability while the long distance runners are more aerobic.
Back to the fish, it was observed that those capable of fast bursts of mobility also avoided capture almost always.
Researchers also explained that evidence to show that fish population experiencing increased fishing pressured appeared to be maturing sooner and becoming smaller although the question of whether this represents an evolutionary effect from fishing pressure remain to be answered.
It was also observed that some fish were better swimmers compared to the others. However, when fish is chosen to be better swimmers, they will need additional energy to live and it is likely that their basic metabolic rates edge up. They could possibly experience lesser reproductive output and their growth itself could be slower. These are perhaps the trade offs for the fish becoming better swimmers and we need to wait for some of these answers.
Intense fishing compels fish to learn faster swimming to stay safe from the trawler nets