“Learning can reduce catchability, but what if some fish were just innately less aggressive at striking?” asks fishery scientist and In–Fisherman Field Editor Dr. Hal Schramm, who goes on to describe how genetics might be responsible for catchability. “In a study that spanned almost two decades, Illinois Natural History Survey fishery scientists tested whether catchability is an inherited trait. Adult largemouth bass in a 17-acre impoundment were fished for a summer and marked each time they were caught. The lake was drained, and fish caught multiple times. The “high-catchable” fish were then stocked into a pond to spawn. Bass that were caught infrequently or not at all the low-catchable fish – were segregated into another pond to spawn. Their progeny were reared to adults, fished, and again the high-catchable and low-catchable fish were spawned in separate ponds.”
Fascinating. “After three generations of selective breeding, the catch rate of the high-catchable fish remained the same, but the catch rate of low-catchable fish declined with each successive generation,” Schramm explained. “Vulnerability to capture – catchability – was a heritable trait. Other studies support fishing-induced heritable changes in bass behavior and physiology. The implication is clear: angling, through harvest or even with the relatively low mortality associated with catch and release, can, over time, reduce the catchability of the bass population.”
But what if those bass that never bit are just smarter than others? There might be no way to measure smallmouth IQ, but higher levels of intelligence can also be inherited, especially when segregating high-catch-rate bass from low-catch-rate bass for generations. It’s counterintuitive to continue believing, as so many anglers do, that fish are stupid. The brain of a smallmouth might be the size of a pea, but — cognitively speaking – it’s thousands of times smarter than any comparably sized computer.
This informative article was in the winter issue of In-Fisherman. Our next newsletter will have more interesting research that may explain why your old “tried and true go to bait” isn’t as effective as it once was.