Perch-Bluegill Connection: When to Chase Which

Last winter, after years of testing a theory he was unable to shoot holes in, Dave Genz decided it was time to talk about the connection between jumbo perch and slab bluegills. This winter, it’s time to talk about when to chase which.
Both are ground-breaking concepts:
* Many lakes blessed with big perch also hold bigger bluegills. This is a real-world correlation that appears to be linked by causation. The basis for Genz’s belief is that jumbo perch chow down on massive numbers of tiny bluegills, trimming the numbers so significantly that stunting is prevented or at least minimized, allowing surviving ‘gills to reach impressive size.
Based on his own experience, Dave has come to the conclusion that lakes holding perch larger than about 8 inches have the potential to consistently harbor big bluegills as well. This is an important discovery that we will write more about in the future.
* Despite this predator-prey relationship tying tiny bluegills and big perch together, the two species don’t mingle much after the ‘gills get big. So even though they’re in the same body of water, they tend to be found in separate locations, and tend to bite best under differing conditions. This allows anglers to chase one or the other, consistently picking the more likely target after eyeing up the day.
And now, the details of Dave’s ideas on when to go after either perch or sunfish.
Perch Days
Those bright sunlight, squint-your-eyes blue-sky days are the ticket for jumbo perch in deeper water. “When that big high pressure comes in,” says Genz, “shallow-water fish are more affected by the pressure change than deep-water fish are. You want to fish the deeper water, after the snowstorm moves out and the cold front comes in.
“The shallow weeds can be full of nice bluegills, but at that time they bury down in the weeds farther, which makes them a lot less accessible.”
Meanwhile, under those bright high skies, deeper-water perch can be biting good.
Dave’s theory on this: because the fish (often perch) in deeper water “already have more pressure on them” they experience less change, relatively speaking, when high pressure moves in. This can save the day under cold-front conditions!
So how deep is deep, when it comes to this apparent pressure variable?
He uses 20 feet as the dividing line, in his fishing experience.
(As a point of reference, scuba divers are taught that they will experience ‘one atmosphere’ of pressure against their bodies when they get below about 33 feet. The pressure you feel against your body – same would apply to fish – is the combined weight of all pressures above you, including air and water pressure.)
The question begging to be asked: what about water clarity? What if the water is relatively dirty? Might we expect to see a situation where the shallow-water fish actually bite better under the bright skies?
Not necessarily, says Genz, although he mentions that it’s a matter of extremes. The main factor that comes into play here is that, in darker waters, there are typically few shallow fish.
“Generally,” he says, “fish are deep in dirty-water lakes. We don’t have as many fish in the shallow water, period. In dirty water, the weeds die off in the winter, and the fish migrate to the deeper water.”
Visibility is another variable in your favor on those sunny days, as you attempt to catch deeper-water fish such as jumbo perch.
“Your lure shows up better,” surmises Genz, “because there’s a little more light down there.” He adds that there is never glaring light at depths beyond about 30 feet, no matter how clear the water. “Gold jigs have always been good for deep perch, and this is just a theory, because we can’t see what the fish see, but maybe they can see it from farther away on those bright days. That might help you attract fish from a longer distance.”
This all makes sense, knowing that we are often trying to find and attract perch across vast deep basins and flats, and can only attack one hole at a time. “When you have acres and acres, or miles and miles, of the same thing,” says Dave, “that could be the key, that they have a better chance of seeing your bait from a distance.”
In fact, the way he thinks about it is this: “When it’s cloudy or darker down there, you might say it’s harder for them to find you. You’re doing the same things on cloudy, dark days, but it’s harder for the perch to find you because they can’t see as well.”
Bluegill Days
You already know what’s coming next. On classic ice-fishing water, where clarity is at its seasonal best under a covering of ice, there can be green (or at least standing) weeds in the shallow water, and plenty of nice bluegills in those weeds. But when those high-pressure, blue-sky days come along, “they bury down in the weeds farther,” says Dave, “which makes them less accessible. They swim into the thick weeds to find a place to sit, so how do you fish ‘em?”
So on one of these lakes that features both big perch and nice ‘gills, the best days to target shallow-water bluegills are under low barometric pressure and low light. When clouds cover up the sun, and things are just right, you can call that a bluegill day.
“On those days of low pressure, when there’s maybe a storm coming in,” says Genz, “the fishing generally gets better. The pressure has dropped down, so the fish react as hungry, there’s not as much pressure against them. This is when you can go into the shallows and catch nice bluegills in the middle of the day.”
Having said all this, in his usual style, Dave immediately reminds us that on those high-sky bluebird days, there is often a great, but brief, bluegill bite as the day brightens in early morning and again as the sun hits the tops of the trees and is going down in the afternoon.
“But I’m talking about finding a day when you can go out there and catch big bluegills, steadily, or at least in flurries, all day long,” he says. “When it’s low light and light pressure, those fish come out of the weeds, work the edges, they’re moving and feeding more.”
Note: Dave Genz, known as Mr. Ice Fishing, was the primary driver of the modern ice fishing revolution. He has been enshrined in the National Fresh Water Fishing Hall of Fame and Minnesota Fishing Hall of Fame for his contributions to the sport. For more fishing tips, go to http://www.davegenz.com. Attached Photo Caption: It was cold, but it was also cloudy, so on this day, Dave Genz chose to target shallow-water bluegills. An excellent decision, as you can see. Had it been a high-sky, high-pressure day, Genz might have elected to go after deeper-water jumbo perch instead. (Photo: http://davegenz.com)

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