August 13, 2021
Scooping out nests, laying eggs, warding off nest invaders, staring down or dodging toothy opportunists for days on end. Whew. Time to kick back on the nearest weedflats and eat some bugs. Weary bluegills must view the weeks after spawning the way we approach a trip to the beach.
The spawning and postspawning habits of bluegills are among nature's most wonderfully varied activities. Habitat and latitude have a lot to do with these differences. In the far northern extremes of their range, bluegill spawning tends to be squeezed into a few weeks, maybe a month. In Florida, Okeechobee bluegills begin spawning in March and continue through August. Moving north, the span of spawning activity gradually declines—the window shrinking in step with the severity of winter. But postspawn and summer patterns are determined by the nature of the habitat.
Captain Mark Shepard guides for bluegills on Lake Okeechobee. "The spawn is amazing here," he says. "Bluegills start during March and waves of them keep spawning through August. They only spawn once per year here, but during every full-moon phase a new group begins bedding. Okeechobee has miles of wetlands, flats, and sandbars—lots of cover that offers good Beetle-Spin fishing.
"Immediately after the spawn, bluegills go back out into the main lake. It's like an abyss out there. They disappear in 12- to 15-foot depths on miles of featureless flats chasing young-of-the-year shad. You can fish out there for years without finding them. It's like being on the ocean. It's one of the only fisheries in the U.S. where they haul-seine bluegills commercially. Once the 'gills go out past the reef, even the seiners are out of luck."
Spawning tends to occur first in protected bays on the north side of lakes, reservoirs, and backwaters, where sunlight reaches more water and warms it fastest. Spawning takes place at similar water temperatures everywhere, but can begin in cooler water up North, in the mid- to high-60°F range. "Spawning begins in water temperatures of 65°F to 70°F here, depending on the spring we've had," says David Weitzel, fishery supervisor for the Minnesota DNR in Grand Rapids. "Here, females only spawn once, but males might spawn more often.
A good bluegill lake is less than 30 feet deep, well vegetated, with lots of emergent vegetation like bulrushes, lily pads, wind protected bays, or backwaters that warm up fast. Those are the most important components we've found. Wide-open basins with lots of wave action are less desirable if bluegills spawn in shallow water, but big ones often spawn deeper. The biggest males get the prime spots. Not all spawn at the same time. They start around Memorial Day and waves of bluegills spawn at different times in different areas through June."
Matt Diana, fishery biologist for the Michigan DNR, says what bluegills do next depends on the lake. "Right after spawning, movements are tied to topography, substrates, and the overall character of the lake," Diana says. "When I worked in Illinois, we saw bluegills move to drop-off areas in reservoirs as the water warmed. They tend to get pushed down into preferred zones of temperature and oxygen. Later, the shallows get more anoxic as surface waters heat up, driving bluegills deeper.
"Mostly, these reservoirs stratify," he says. "As long as there was oxygenated water, bluegills would go down 20 to 30 feet. If the lake has deep-water prey, bluegills will be there by mid- to late summer. Movements tend to be associated with prey shifts, but for most of their life they feed heavily on zooplankton. They shift to invertebrates in summer where they can. Research shows they shift back-and-forth, and as they get older they can shift back to zooplankton. Offshore patterns are based on zooplankton. You can have virgin populations in a lake because they split into different groups that feed on different kinds of prey, each living in different kinds of habitats. So it depends on what the lake has to offer."
Minnesota DNR research scientist Jeff Reed has studied bluegill movements. "Biologist Brad Parsons and I tagged fish on the Alexandria Chain of Lakes, which connects 10 different lakes," Reed says. "We were surprised how much movement there was throughout the chain as 16 to 32 percent moved from lake to lake—several miles in many cases.
"Spawning started in the mid-60°F range, right after bass," he says. "Stress from spawning keeps bluegills near shoreline vegetation right after the spawn. They stay for quite a while and mortality is high due to angling and predation. A lot of males disappear. Fish we tagged were all 7 inches, so a little too large for most predators in these lakes."
Some bluegill experts believe bigger bluegills spawn deeper. Max Wolter, Senior Fisheries Biologist for the Wisconsin DNR, and leader of the state's panfish research team, says "We find bluegills spawning in 10 feet of water in Chippewa Flowage. I don't know if it's related to bluegill size. If that pattern exists it's because deeper colonies aren't fished as hard. Deep bluegills are less pressured and can get bigger."
Reed says he's heard anglers say that deep-spawning bluegills tend to be larger, but he hasn't seen evidence of it. I suggested he might want to join a particularly effective bluegill guide in his district named Garett Svir, who had just sent me a screen shot from SideScan on his Lowrance HDS Carbon. The image looked like the surface of the moon with craters everywhere—bluegill beds in 12 feet of water.
A Guide's Take
"The peak of the spawn, where I fish in Otter Tail County, Minnesota, is typically during the first full moon in June," Svir says. "But I caught males on beds until July 12 last year, probably because June was cold. Small, fertile, prairie lakes with heavy nutrient load are my best producers. Bottom types vary. In one lake, bluegills spawn on lily-pad roots, right at base of the pads. That lake gets choked with vegetation. When I don't know a lake, I look for bulrushes. Hard-stem bulrushes grow in the perfect substrate for spawners in most of these lakes.
"I cruise the area outside bulrush stands at 3.5 mph, looking for deeper beds with SideScan. That's where the big fish are. When I spot a few, I put the bowmount down and zoom in with SideScan to get a better picture. Big ones spawn in 12 feet of water. You can count the number of fish on the beds with SideScan. It blows people's minds. Another great location to look for spawning 'gills is an inside weededge with sparse sandgrass. That's prime."
Svir finds that the biggest bluegills in the systems he knows tend to be first to spawn and first to finish. "For big fish, postspawn might be as early as 74°F," he says. "The spawn can continue for a while and not all 'gills are doing the same thing at the same time. When the water reaches 80°F, I consider it to be postspawn and adjust my tactics accordingly. But if we're catching all females or mostly females fishing a postspawn pattern, it pays to go back and recheck spawning beds with StructureScan and SideScan for big males. They sometimes remain, protecting nests.
"I had a client out and we were on big numbers of medium-sized females along a deep weededge during a time I presumed the spawn was over in mid-July," Svir says. "We decided to look at some spawning areas with SideScan and found a few isolated fish that appeared as white dots. After a slow grind we boated two males in the 11-inch range. Side-imaging with the HDS Carbon is a game changer."
Wolter says bluegills recovering after dropping eggs and defending nests won't move far from spawning sites for weeks. "Right after the spawn in these deep clear lakes, they move out a little deeper but not far," he says. "Usually they're bottom-oriented, adjacent to spawning areas in 4- to 6-foot depths, in or adjacent to shoreline weedbeds. That lasts a few weeks and then they split into various patterns."
Svir's experiences bear out many observations of biologists and guides from other regions. "During the postspawn, I usually look for 'gills on flats just outside cabbage and coontail edges," he says. "That's where the big ones are. Getting tight to the thick edge produces fish. Clients hire me to catch trophy fish for a reproduction or photo. Fishing slightly deeper adjacent to cabbage and coontail edges in the 12- to 15-foot range is the big-fish pattern most days. The best areas on these flats have isolated patches of cover just starting to grow. Bull bluegills are risk takers and roam slightly deeper because of their size. They stray farther from cover to take advantage of better feeding opportunities.
"Most of my postspawn targets are close to the bottom, so making bottom contact is critical," he says. "Bites can be light during this period, making a sensitive rod important. I like JT Outdoor Products Panhandler rods. The blanks feature a zonal spun carbon that provides backbone where you need it and maximum sensitivity. A whippy noodle can't produce the jigging cadence I like. Time and again, a harder jigging action catches the biggest bluegills. I try to jig in place with something they can feel in their lateral line but without much up-and-down movement.
"My setup during postspawn typically consists of a larger spinning reel to limit line twist, spooled with 4-pound Berkley Trilene XL. I place a large split shot about 18 inches above a Northland Gill Getter Jig. That's my confidence rig. I can move with the trolling motor and keep the rig vertical. You want to jig it hard and work an area slowly with the bowmount while keeping the presentation completely vertical. During postspawn, I switch from plastics to a whole redworm."
Isolated cover off the beaten path hides those "virgin populations" Diana described. "Patches of sparse plants and sandgrass on deeper flats become gold as the postspawn progresses," Svir says. "There will be bluegills there. I use down-scan to pick fish out of the vegetation. Looking for suspended bluegills is a waste of time during postspawn. Key spots may be related to the location of burrowing insects. There, the bottom isn't really firm, not really soft, and 'gills are pinned to it. Bottom contact becomes critical. I like to shake the rod hard—not a lot of up and down but making the jig actively work in place. I like the biggest Gill Getter—1/32-ounce with a #10 hook—with a whole redworm or small leech."
Shepard says the last chance to intercept Okeechobee bluegills after each spawn, before they evacuate into "the abyss," involves crickets, Beetle Spins, and flyrods. "Mature 10- to 11-inch fish are common," he says. "We cast with ultralight spinning rods spooled with 5-pound braid or 6-pound monoâ€”sometimes 10-pound around heavy grass. I like 6- to 7-foot rods. In tall grass we use crickets under floats on bare hooks. Sometimes we fly-cast with 4- to 6-weight equipment, floating lines, and poppers or slow-sinking bugs. Or we work Beetle Spins around and through cover with long casts and steady retrieves."
By August Up North, however, bluegill patterns become a crazy quilt, and some patterns are overlooked. "A bit later I find bluegills on hard-bottom humps that top out at 12 to 15 feet," Svir says. "They're not out there at postspawn. It's a late-August and September pattern. I like to fish a Clam Leech Flutter Spoon. You need more than a split shot and jig to cover that big structure effectively. It gets vast out there sometimes. I use faster 7-foot rods to pound jigs and spoons harder on 4-pound Trilene XL. Anything thicker hampers lure movement." In Illinois and Michigan, Diana finds that bluegills move out of vegetation into open areas by midsummer. "Smaller bluegills stay in cover until low-light," he says. "Larger ones are bolder and less vulnerable to predation. Then we see some in open water, some go deep, and some stay on weedflats. Bluegills are so abundant in most lakes they need to spread out to avoid competition."
According to Sivr, bigger bluegills are the first to move to deep rockpiles (20 feet or deeper), or suspend, following wind-driven veils of plankton across open water. These patterns are rarely exploited by anglers. But the best patterns in shallow, dish-shaped lakes with little structure tend to involve deep weededges all summer long.
By August, in larger, more complex lakes, I explore main-lake weed humps that top out at 12 to 15 feet by swimming 2-inch grubs on 1/32- to 1/16-ounce jigs over the vegetation. Over reefs or rockpiles down to 30 feet or so, we fish vertically with Venom Inferno Spoons or TC Tackle Jigs—1/8-ounce heads with small hooks tipped with redworms or leeches. When we find a good bite in either case, we may back off and pitch to the area with slipfloats and smaller jigs under a balancing bulk pattern of small split shot.
If the wind has been blowing in the same direction for days, we control-drift over open water along the windward shore with small Bait-Rigs Tackle Willospoons or Custom Jigs & Spins Pro Series Slender Spoons. Suspended 'gills tend to be in the top 10 feet of the water column, so we use one small split shot or no weight, moving at .6 to .8 mph. For all these patterns I use 7- to 8-foot St. Croix Panfish Series Rods and moderate-sized spinning reels spooled with 4-pound Berkley FireLine or 4-pound Maxima Ultragreen mono.
"Bigger fish are the risk-takers in shallow prairie lakes," Svir says. "They explore food sources outside deep weededges. I try to find extensive coontail and cabbage beds on those lakes first. Big bluegills roam a lot farther from weededges than little ones. So I cruise the flats and hunt for them outside weededges in depths of 10 to 15 feet. Big bluegills are out on the beaches, soaking in some summer heat, kicking back and getting fat. We hate to spoil their fun, but we do send the big ones back to keep the fishery thriving."