Posted on 06/17/2015 7:53:48 PM PDT by nickcarraway
A study of lakes in Connecticut reveals that recreational angling pushes largemouth bass to evolve.
Fishing a lake may, over time, make the fish in that lake harder to catch. A new studysuggests that recreational fishing, aka angling, causes evolutionary changes over the course of decades. Largemouth bass living in waters popular with anglers have been adapting to become less active. New generations of increasingly timid fish may eat less and be less likely to bite.
“When your grandfather told you the fishing was better back in his day, it’s possible he was right,” says Jan-Michael Hessenauer, who reported the finding online June 3 in the journal PLOS ONE.
Now a graduate student at the University of Connecticut in Storrs, Hessenauer caught his first fish as a child, using a wooden pole his dad made. He spent his youth fishing for fun at his uncle’s cottage on a lake and in the cold streams of northern Michigan.
In the fall of 2012, a year after coming east, Hessenauer went fishing for largemouth bass in Connecticut’s Amos Lake and Gardner Lake — for the sake of science, not sport. In the early part of the 20th century, people ate their catches, but recent decades have seen the rise of catch-and-release, and now most fish are thrown back.
Curious about how this activity has affected the bloodlines of the fish in those two lakes, Hessenauer captured some baby bass using nets and electric stunners. For comparison, he also collected babies from two reservoirs owned by water companies that have long prohibited fishing. After raising fries from both sites in an isolated pond for 10 months, he and his team then measured how much oxygen the fish consumed when at rest. This provides a proxy for metabolic rate, which relates to how active a fish is.
The lake-born bass had slower metabolisms. Animals tend to inherit their metabolisms from their parents, so this discrepancy between reservoir and lake fish could be an example of evolution in action.
For a fish living in a placid reservoir undisturbed by anglers, having a high metabolism — and thus a more aggressive demeanor — would be a good thing. Bolder males are better at defending their nests from other males and critters intent on gobbling up their eggs or newly hatched young. Their protected offspring would be more likely to survive and grow into bold males that are themselves more likely to pass on their DNA to their offspring.
But for a fish trying to get by in waters teeming with sportsmen, being aggressive could actually be a bad thing. A pugnacious fish would be more likely to strike an angler’s hook and disappear — leaving its progeny defenseless for a short time or forever, depending on whether the fish gets thrown back into the water and whether it survives the ordeal. Such fish would also be more likely to go after a wriggling worm on a hook in pursuit of food outside of the spawning season. In short, fishing pressure allows the meek to inherit the lake.
“The fish adapt in the face of a new predator, humans, and evolve to become less aggressive,” said David Philipp, an angler-turned-biologist who chairs the board of directors for the Fisheries Conservation Foundation in Champaign, Illinois.
Philipp spent decades showing that fish can be bred to become more or less aggressive. In the 1980s he invited anglers to cast in ponds he had seeded with bass. When fish that were caught three or more times were mated, generation after generation, their family line gained a higher metabolism. Fish that were caught once or not at all gave rise to another lineage with a lower metabolism. The new study is the first to suggest this change in metabolism under natural conditions–though Hessenhauer can’t be 100 percent sure that differences between the lakes and reservoirs other than fishing levels could be to blame.
What the change means for the lifestyles of bass remains an open question. Creatures born with slower metabolisms tend to mature and give birth at a younger age.
Like lions or eagles or crocodiles, bass are apex predators at the top of their environments, so changes in the diets of bass could also have a trickle-down effect on the other inhabitants of their ecosystem. Hessenhauer and his colleagues calculated that a 2-pound (0.9-kilogram) fish from one of their angled lakes would eat about 0.5 fewer Calories per day of the fishing season than reservoir-born fish. That means more of the bass’s prey can survive. Which means less of the prey’s prey can survive. And so on, and so forth.
“Although this change in caloric consumption might seem small, once you multiply it by the number of individuals in the food web it has the potential to make some relatively substantial changes,” said John Post, a biologist who studies trout at the University of Calgary in Alberta, Canada, and wasn’t involved in the new study.
Whether other kinds of large fish in other lakes in other places are evolving is unknown. Bass in New England may experience more pressure to adapt than their peers elsewhere. Species inhabiting lakes in the South, for instance, can have a longer breeding season that provides more chances to reproduce. They also tend to live in larger populations that dilute the impact of fishing on each fish.
“We need more research to see how things differ by location,” said Hessenhauer. But even though the impacts of evolution on lake fish remain far from definitive, he encourages managers of lakes to consider how much pressure is being put on their fish. The big catch-and-release tournaments popular with anglers may, in the long run, have repercussions on the tournaments themselves.
Its not a stupid study because fishermen spend money. And the taxpayer dollars that pay for it come out of the pockets of fishermen(licenses and excise taxes on fishing equipment and supplies).
They have known about this a long time and most states use a largemouth breeding program to counter the this phenomenon.
“Timid” and “Aggressive” genes existed in the bass and were not added due to mutation.
Indeed, as you said, it’s not “evolution” when the aggressive ones are caught and don’t pass on their traits. It’s an environmental “forcer” that allows the less aggressive bass to reproduce more.
It is a form of selection, albeit “unnatural”. But it’s not evidence of “evolution”.
I have a lot of experience fishing smallmouth in the Ouachitas and I will tell you that the streams in AR are better fishing than the ones in OK. The Cossatot is the best but there are places on the Little Missouri that are good.
The first thing you need to do is look at the USGS river guages on the river that intend to fish(found on the internet). Tropical storm Bill probably has the river running high which will kill the fishing.
As some suggested, inline spinner baits always work well. Mepps and Panther Martins are the highest quality. The Rooster tail is a cheapy that often malfunctions(won't spin). Floating/diving crank baits 2-3 inches long work very well and can be twitched as well. But they have to be shallow running because you will be fishing shallow water.
It is best to wade fish them as boats/canoes spook the fish. If needed, use a boat as transportation down river, but fish on foot. Wear light weight pants made of polyester that don't hold a lot of water and wear good booths made of synthetics. Thick soles will protect your feet. Be careful because the bottom of those rivers are slicker than owl shit; don't walk on flat rocks. Also be careful because the cottonmouths are aggressive.
The best seasons are Feb 15- April 1 and Oct 15-Dec 15. Its gets damn hot down on those rocky rivers in May, June, july, Aug, and Sept.
Catch and release.
Those monies derived from licenses go into a 'general fund',
and are not identified nor directed to go into fisheries expenses or maintenance.
Well , that's not how it is here , behind enemy lines.
Micro-manager Andy Cuomo considers the 'general fund' as his personal piggey-bank of goodies to be distributed among the government elite as re-election favors.
Congrats on being in a reasonable state ; my loss (for now).
“What equipment do I need to buy and what lures should I use.”
Sticks of dynamite work very well.
Thanks for your insight. Having grown up in Arkansas I know all about the cottonmouth. During mating season, which is April and May if I remember correctly, they will attack ANYTHING in their territory. And when they bite, they don’t let lose. Scary stuff.
What is your opinion on wearing waders?
I’ll be on the river the 29th so hopefully Bill will have done it’s damage and be done with. From what people are telling me the fish are down deep in the cooler water.
Maybe I can catch a few. Personally, crappie and bass are the best tasting fresh water fish.
Smallmouths in Missouri in very clear streams are fun to catch on fly rods with trout lures, or leadhead maribou jigs on spinning reel rods. Try different colors, for me, brown or black , white, and varied shades of green, covers different light conditions and work just fine. Haven’t had much luck with red or pink.
4 lb test is fine. If you’re not using a spinner or spoon but a very light leadhead marabou jig , trim the feathers so they aren’t too long or else timid fish will just grab the part aft of the hook. Cast, then let it sink a bit. Then pull the rod up slow, then reel as it comes back down, repeating in short bursts so the feathers get a chance to flare out periodically. You want it to look like a nervous minnow coming up to snatch a bite and retreat to the bottom.
If there’s weed on the bottom you can add a tiny bobber.
Works on trout too... sage green looks like an aquatic bug.
Here they talk about funding with most of their money coming from the Conservation Fund which collects the license fees.
The second source is the federal aid which is the federal excise tax on fishing, hunting, and boating.
The third source is the general fund.
The State of Texas also has an excise tax on sporting goods. A fishing lure in Texas is very high priced but it includes the 12% fed excise tax and the 12% state excise tax
Stream fishing is vigorous activity because you are usually walking over rocks, constantly stepping up and down, like walking up and down stairs.
Thanks for your advice. My wife called the place a while ago and the guy told her it flooded but the cabins didn’t get any water. I said “Good. That means there shouldn’t be any snakes hiding under the beds.” Now I just need to find me some stove pipes to wear over my legs.
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