Anglers may be influencing the evolution of bass and the consequences do not look promising, according to a ground-breaking study by the Department of Natural Resources and the Environment (DNRE) at the University of Connecticut.
“This scenario genetically favors the fish with lower metabolisms, the fish that are less likely to be caught by anglers,” said researcher Jason Vokoun. “It suggests that we may be permanently changing exploited fish populations over the long term.”
And what we might be changing them into are the aquatic equivalent of couch potatoes, fish not as likely to be caught because they are less aggressive.
The potential for recreational fishing to act as an evolutionary force is well established as a theory, according to the university. “But this is the first study to identify outcomes of selection from recreational fishing of wild populations using unfished populations as reference,” it said.
In the study funded by the state Department of Energy and Environmental Protection (DEEP), scientists collected young bass from fished and unfished lakes. After being tagged to identify their places of origin, the fish were released into protected waters. A year later, researchers collected them and measured their resting metabolisms.
They found that a significantly higher number of fish taken from the lakes where fishing was allowed had lower metabolic rates than bass from unfished waters. “This results point to a reduction in the type of behavior that is so prized by anglers,” said Jan-Michael Hessenauer, a doctoral student.
Why is this happening? Scientists aren’t as certain about that. Possibly nests guarded by more aggressive males fail more often because those fish are caught, and, as a consequence, the genes of those fish are not passed on. Or maybe more aggressive females that are caught and released suffer physiological stress, resulting in egg resorption and fewer offspring.
In an attempt to learn more, scientists now will interbreed the two populations, with the hope that the offspring will inherit the more aggressive behavior of the fish from unpressured waters.“The findings in this study may be a strong signal that we need to be much more creative in the ways we manage our inland fisheries,” said DEEP’s Robert Jacobs.