Anglers in saltwater and fresh water have been insisting for generations that fish get “smarter” — refusing to bite certain baits after repeated encounters.
But a team of researchers from the University of Florida’s Fisheries and Aquatic Sciences program has come close to proving this old axiom scientifically.
Graduate student Nick Cole and colleagues — all avid bass anglers — conducted an experiment in a private, 27-acre lake outside Gainesville in 2012 “to see if catch-and-release angling would make fish more or less vulnerable for subsequent catches and whether that vulnerability would be different between very different lure types,” Cole explained.
Devil’s Hole Lake had very little angling pressure when the scientists/fishermen got there. But before breaking out rod and reel, they used electro-fishing gear to gauge the bass population — 347 fish greater than 10 inches. Then UF technicians Matt Young and Davis Waldorf fished three days per week for four weeks using two very different lures — a chrome-and-black lipless Rat-L-Trap crankbait and a four-inch, plum-and-emerald-flake Gary Yamamoto Senko stick bait fished weightless with a 3/0 offset worm hook. Both lures were attached to 20-pound braided line with a four-foot, 20-pound-test fluorocarbon leader.
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“We picked them because they are commonly used bass lures,” Cole said. “We wanted to look at two ends of the tackle spectrum.
“The Rat-L-Traps are loud and flashy. With the Senko, there’s not a lot of vibration going on.”
To eliminate bias over different angler skill levels, the researchers fished each lure for an hour and then switched for the next hour throughout the day. They tagged the bass they caught with individually marked electronic tags, then let them go.
Over a period of four weeks, they caught and released 260 bass ranging from eight to 20 inches.
“We found strong evidence that bass learned to avoid capture, particularly for the lipless crankbait,” Cole wrote.
He said recapture rates for the flashy Rat-L-Trap declined substantially — from 2.5 fish per hour to only .25 fish per hour. Recapture rates for the Senko also declined, but not as much — dropping from 1.8 fish per hour to about one fish per hour. The crankbait had the lowest number of recaptures, with only two bass caught twice. With the stick bait, 20 fish were caught twice.
To avoid capture, Cole said, bass might have recognized a lure once they ate it and declined to bite the next time they saw it, or they might have moved to a deeper area of the lake where it would be more difficult for anglers to reach them, or they simply might have become more passive and fed less on whatever came their way.
“We don’t know what that behavior was exactly, but we know there was an impact,” Cole said. “We were able to show very different rates in how vulnerability was changing and different catch rates between the lures.”
Future studies, he said, could test a broader array of fishing lures in a tank, for example, observing fish reactions to them. And he said scientists need to look at how angling pressure affects fish behavior.
“That’s an important topic for management in the future,” Cole said.
Bass anglers should probably take their cue from successful pros such as Kevin VanDam and others who change lures and tactics frequently and still manage to catch big bass consistently.