Largemouth bass are evolving slower metabolisms. They're becoming less aggressive.
The idea that fishing for fun at your favorite lake could change how a fish evolves is relatively new, but Jan-Michael Hessenauer says it's real. He says fish seem to be developing slower metabolisms. That means they're less hungry, and less eager to take the bait from a fisherman.
It all begins with the idea that fish have different "personalities if you will," Hessenauer said. "Some fish, just like people, are more aggressive, some fish are more exploratory."
Hessenauer, a PhD candidate at UConn, said the current theory is that "personality" is tied to metabolic rate. Fish with higher metabolisms need more energy than those with low ones.
"To maintain the same basic functions: growth, reproduction, survival, etc., a high metabolic rate fish is going to need to consume more prey," Hessenauer said. "As a result -- because angling is sort of a predatory act, the fish thinks it's eating something when it gets captured -- a high metabolic rate fish is going to be exposed to angling more frequently than a low metabolic rate fish."
That means fish with higher metabolisms might be less likely to survive in lakes where there's angling.
To test this, Hessenauer analyzed largemouth bass in Connecticut. In a study published this month in the journal PLOS One, he compared fish from public lakes frequented by recreational fisherman to "unexploited" ones from private drinking-water reservoirs, which have been undisturbed for almost a century.
"What we found was that the unexploited individuals did indeed have a higher metabolic rate than the exploited fish," Hessenauer said. Or, put another way, largemouth bass are evolving slower metabolisms. They're becoming less aggressive.
Largemouth bass are predators, so Hessenauer said if they're less aggressive, that could allow lesser-prey species in a lake to flourish.
Hessenauer said state fishery managers may need to consider cross breeding fish to preserve lake ecology.
The work was supported by the state Department of Energy and Environmental Protection and Jason Vokoun, Hessenauer's faculty advisor at UConn.
Going forward, Hessenauer said state fishery managers may need to consider cross breeding fish with higher metabolisms with ones with a lower metabolism -- to preserve lake ecology and make it more likely that the bass will take your bait the next time you go fishing.
