Wednesday, January 07, 2009
Do Bass Remember?
More and more in bass fishing, we hear the pros say that bass are "conditioned." The term usually comes up when discussing pressured fisheries and difficult bites.
Dr. Keith Jones conducts research for Berkley at his Pure Fishing research station.
But do we really know whether bass become conditioned? Specifically, whether they become conditioned to avoid certain lures they see time and again?
There are certainly trends on the bass tours that would seem to suggest that. For example, spinnerbaits – once a dominant presentation for top pros – seem a forgotten bait now. Small worms, swimbaits, frogs and other newer trends have replaced it.
But no examination of tour results is truly scientific, since too many variables factor in, such as venues and seasons.
There has been significant scientific research done on the subject, though. Dr. Keith Jones, who works in the research department of Pure Fishing and is widely regarded as one of the world's foremost bass experts, writes about that research in his book Knowing Bass: The Scientific Approach To Catching More Fish.
Four Types Of Learning
According to Jones, bass "learn" in several different ways. The four main methods of learning are:
Associative Learning – Think of this as trial-and-error learning. The fact that bass are capable of associative learning, Dr. Jones writes, is proven by laboratory experiments "where the animal is taught to link two types of stimuli, such as a certain-colored light with an ensuing electric shock. Bass readily learn these associations, both in the lab and in the field, although not as fast as some other species."
Habituation – This is the type of learning through which bass gradually become less sensitive to particular stimulations. Examples would include fish in an aquarium that no longer shy from people who walk by, or bass that learn to ignore boat traffic on a busy lake.
Spatial – Bass learn to move around their environments, recognize landmarks or objects and stake out home territories. Their ability to do so comes through spatial learning. In fact, according to Dr. Jones, bass in the laboratory have been able to find their way through an underwater maze to reach a desired point.
Prey Images – The fourth type of bass learning that Dr. Jones describes is the ability to develop and recognize prey images. Bass therefore can recognize a shad or crawfish as prey. "Given enough positive experience with a certain prey type, a bass will gradually come to actively seek out that specific prey," he writes. "Prey species, for their part, often counter the bass's efforts by changing their signature stimuli, often through the use of camouflage."
Noteworthy too is Dr. Jones' observation that while bass are capable of these different types of learning, individuals learn at different rates. He cites a 4-year study in Illinois that documented recapture rates of largemouth bass. The average bass was caught twice each season, but some bass were caught up to 16 times in a single season.
"Within every population of bass, some individuals learn to renounce lures very quickly, whereas others never make the mental connection between lures and trauma," Dr. Jones writes. "So much individual variation in learning rates exists that at one time, Texas Parks & Wildlife explored the potential of developing a genetic race of dumb bass."
Bass Memory For Lures
What's especially interesting about Dr. Jones' discussion of bass learning is a study conducted at Pure Fishing that tested bass memory for lures. The results suggest that bass "remember" lures for quite a long time.
In the study, bass were allowed to freely strike a minnow lure for a 5-minute test period. In the initial exposure, most strikes came in the first 1 to 3 minutes. By the end of the 5-minute period, the bass had learned to ignore the lure "since it provided no positive food reward."
The bass were then divided into two groups and held separately, with no additional testing, for different lengths of time.
After 2 weeks, the bass in one group were reexposed to the same minnow lure, again for 5 minutes. The response was one-tenth of what it was in the initial exposure, "indicating that the bass had retained a strong negative memory of the bait during the 2-week interval."
Holding bass for an even longer period yielded similar results. After 2 months, the second group of bass still tested well below the original response level.
Dr. Jones concludes his discussion of the memory study by writing: "The results show that under some circumstances, bass can remember lures for at least up to 3 months and perhaps much, much longer. Who knows? If the experience is bad enough, they might never forget."
What's it all mean for the bass angler? While there are no hard and fast rules in fishing, the research certainly seems to suggest that anglers should try different lures in the same areas, especially areas they fish regularly or that are heavily pressured.
Dr. Keith "Doc" Jones is director of research at the Berkley Fish Research Center in Spirit Lake, Iowa. His book "Knowing Bass, The Scientific Approach to Catching More Fish" is available at Amazon.com, Barnes and Noble, and other booksellers.