Panfish Senses and Triggers
June 12, 2014
One concept we have long used to get anglers to consider what they're doing when they're fishing a lure or a bait is this: The presentation moves we make have two parts, each with different purposes. First, we work our presentation to attract attention in order to get panfish to move in close to check it out. Secondly, we manipulate the lure to trigger fish to bite.
Say we're working a spoon vertically. We lift the lure, let it fall, then hold momentarily. The lift-fall is the attracting maneuver, while the pause usually triggers the fish. We might add twitches to the pause to further tempt (trigger) fish that have been called in.
At times attracting maneuvers also serve as triggering maneuvers. I like to fish tiny crankbaits like the #3 Countdown Rapala for panfish. Another favorite is a miniature swimbait like the 3-inch Storm WildEye Swim Shad. The realistic swimming movements of these lures attract panfish that overtake the lure from behind and eat it — attraction becomes triggering. At other times, it takes a little hitch or pause in the straight swim to get fish to bite. Or, it might take pausing the lure to let it fall to get fish to finally react.
Vision is important, but anglers often overlook the importance of vibration in this process. My search for answers about how vital vibration can be lead me to Bluegills — Biology and Behavior, by Stephen Spotte. An in-depth and enlightening look at the biology of the bluegill proved a good place to find answers about how panfish respond to the vibrations that come from the things that live around them as well as vibrations from the lures and baits we use to fool them. In no other scientific discussion have I seen such detailed analysis of swimming movements and how those movements are sensed by fish with their lateral line.
Spotte talks about the hydrodynamic vortices generated by fish as they swim. He says: "The wake left by a swimming fish or other aquatic animal slowly attenuates (dies: my word), but not without alerting intercepting predators or prey of its owner's location and distance. These hydrodynamic 'trails' have been playfully called 'fish footprints.' The size of a wake depends on the size of the fish, but its morphology varies by species. If 'fish footprints' are indeed unique to species, and if they can be recognized and used to advantage by conspecifics or predators, they might better be named 'fish fingerprints.'"
Spotte says that trails remain distinguishable from the background noise for several minutes and may, in still water, remain detectable after 5 minutes. He mentions the process by which a muskie goes about finally feeding on a prey species — after saying that fish, without any visual cues can continue to feed effectively using only their lateral line, but they can not continue to feed effectively when the lateral line sense is blocked.
Spotte reports that a muskie feeds in two phases: "it sulks stealthily toward its prey using the pectoral and caudal fins, then strikes quickly. The process involves vision for initial target detection, but the lateral line assumes dominance during the strike."
So, look at what we've learned. Fish happening through the "trail" of another fish can tell what fish species it is (finger print it) and perhaps even tell if it's swimming badly — wounded or injured. Likewise, predatory fish also don't have any trouble tracking a school of minnows or other small prey fish, sensing the school in larger context as it moves.
Surely this explains why fish like bluegills and crappies in deep water where vision is limited suspend motionless for long periods. Like the starship Enterprise in space, sensors on alert, they're waiting for their lateral line sense to pick up the movements of tiny prey species, fish fry or aquatic insects. Even without adequate vision, once the prey is moving they can track and strike.
This likely also explains what's at work when fish see and then track and strike a lure like a small swimbait or a crankbait — or even a small curlytail plastic. We know the lateral line sense is for close-quarters sensory perception having to do with low-frequency vibrations.
Once a fish sees something interesting it swims steadily toward the offering, gets behind it, and tracks it — or just swims up and stops. Once the lure or baitfish is in a zone a foot to inches in front of the fish, vision is important, but so too has the lateral line sense kicked in. Often the fish almost goes on autopilot, relying on the lateral line to make the final judgment about whether or not to eat the thing. Again, at times it's the lateral line, not vision that tells a fish to break off the chase and avoid the lure at the last second — or to go ahead and eat it.
The reason certain lures often so completely fool fish must be because the lateral line is getting feedback from something that feels perfectly natural as the fish closes in, traveling in or holding in the vortex of the lure. It has to look alive — and it better also feel alive.
Editor's Note: Bluegills — Biology and Behavior, by Stephen Spotte, is a publication of the American Fisheries Society, fisheries.org