CHAMPAIGN, Ill., 9/27/19: Largemouth bass apparently don’t learn to avoid fishing lures from other bass but instead from their own past experiences, according to University of Illinois research.

Some scientists at the Illinois Natural History Survey (INHS) study fish behavior, in large part for clues on how fish change over time in response to fishing. Fish are caught less often as they learn to avoid baits and lures. A recent INHS study evaluated the question of how that learning happens.

One way that fish learn about their environment is through social interactions with other fish of the same species. Taking social cues is expected to sway their behavior more quickly than if fish need to experience being caught first-hand.

“The mechanism for how an individual fish learns to avoid lures is still largely unknown,” said INHS fish ecologist Jeff Stein. “What if they see a neighbor getting caught? Are they learning from other bass that disappear? Do they learn by sight or by a chemical or other signal? We tried to find out how this is happening.”

The INHS researchers stocked four small ponds with 160 fish that had not previously been caught (demonstrators) and one large pond with 152 inexperienced bass (observers), then fished two of the smaller ponds so that the demonstrators would have experience with lures. Researchers then placed the observers into all four small ponds and fished in all the ponds again over several days.

After observing how many fish of each type were caught in each pond, they found no difference in the catch rate of the observer fish, whether or not they shared a pond with experienced demonstrators. So, in heavily fished areas, largemouth bass are unlikely to learn to avoid capture simply by being in and around other fish that are captured, which is good news for anglers.

A significant number of fish were caught more than once, showing that fish may have to experience being caught several times before they learn that chomping the bait is a bad idea.

When the bass were introduced to unique lures, more were enticed to bite the line. By simply using a different color lure, more fish were captured initially, but the catch rate soon fell off as fish learned from experience to avoid the recognizable bait. The number of fish caught declined steadily over 12 fishing sessions.

When the researchers used a radically different lure—in this case a spinnerbait—they received a much more dramatic result.

“The number of fish caught shot up, but then dropped within four angling sessions,” Stein said. “Anglers have known for years that they need to change their lures in response to changing conditions, but now we have the data to show that even if conditions are stable, making regular lure color and style changes should make for a better day of fishing.  But there are no guarantees!”

The study was published in the journal Fisheries Management and Ecology.

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Media contact: Jeff Stein, 217-244-1516, jastein@illinois.edu
Tricia Barker, Associate Director for Strategic Communications, 217-300-2327, tlbarker@illinois.edu

Related story: https://news.illinois.edu/view/6367/546506