Scientists have disclosed genetic changes that cause rapid fish evolution due to intense harvesting for the first time – changes that beforehand had been invisible to researchers.
Over recent decades, many commercially harvested fish have grown slower and matured earlier, which can interpret into lower yields and a decreased resilience to overexploitation. Scientists have long suspected fast evolutionary change in fish is caused by intense harvest pressure.
“Most people consider evolution as a very slow course of that unfolds over millennial time scales, but evolution can occur very quickly,” stated lead creator Nina Overgaard Therkildsen, professor of conservation genomics at Cornell University.
The paper, “Contrasting Genomic Shifts Underlie Parallel Phenotypic Evolution in Response to Fishing,” was published in Science.
In closely exploited fish shares, fishing almost always targets the most significant individuals.
“Slower-rising fish will be smaller and escape the nets higher, thereby having a higher chance of transferring their genes on to the next generations. This way, fishing could cause a rapid evolutionary change in growth charges and different traits,” Therkildsen said. “We see many indications of this effect in wild fish stocks, but nobody has known what the underlying genetic changes have been.”
After only four generations, the harvesting had led to an evolution of an almost two-fold difference in adult size between the teams. Therkildsen and her staff sequenced the total genome of nearly 900 of those fish to examine the DNA-level changes liable for these striking shifts.
Surprisingly, these significant shifts only occurred in a number of the populations, based on the new paper. This means there were multiple genomic options for the fish in this experiment to get both more substantial or smaller.
Research like this may assess human impacts and enhance humanity’s understanding of “the speed, consequences, and reversibility of complex adaptations as we continue to sculpt the evolutionary trajectories of the species around us,” Therkildsen mentioned.