Bluegill Fishing Rivers
April 07, 2014
The Seminole tribe declined invitations from our government to follow the Cherokee, who mostly died of broken promises on the Trail of Tears. Instead, they retreated into the Everglades and have never, to this day, surrendered. In that dense, impenetrable morass, the U.S. Army could rarely find, enclose, or even engage their enemy without horrific consequence. In swamps, nature is a formidable ally.
River bluegills are the Seminoles of the piscatorial world. Bluegill fishing rivers, when backwaters choke with cloying vegetation in early summer, many anglers believe the brahma bulls of Clan Panfish can no longer be approached, largely because they have assaulted the reticent rascals with super weed-eating trolling motors, push poles, flat bottoms, waders, meat rods, and braided line. Like the Army, they limp back out drenched in sweat and grime if they return at all, livewells empty, spirits broken.
With regard to the density of trophy bluegills, many river backwaters serve the same purpose as quality regulations by simply refusing to allow access to the fish for a large part of the year. Ice fishing and spring invasions are popular in backwaters, and many offer summer fisheries, too. In perception, backwater areas can become inaccessible. If we cannot access, we cannot harvest. If we cannot harvest, the fish grow. If they grow big enough, they will break lines and hearts among the fallen timbers.
In reality, however, river bulls may not be as inaccessible as most people think. During drought years, we've been catching bluegills in the middle of the Mississippi River, out in the open, in places where few anglers have ever reported catching them before. This led to further inquiry and, in turn, to the understanding that river bluegills use main-channel areas far more often than most of us previously understood.
River 'gills need to escape flowing water in winter because swimming ability decreases dramatically as water temperatures drop toward the freezing point. When temperatures get cold in fall, they vacate the channels and return to backwaters or connected lakes. Deep river pools rarely provide an option anywhere north of Georgia. Since wintering areas need to be completely out of the flow, bluegills tend to be found in connected lakes, in reservoirs downstream of summer areas, or in connected backwaters and sloughs just about everywhere between December and March. Bluegills tend to require deeper water in winter, but river bluegills with no other options can survive in backwaters no deeper than 4 feet, even in the Upper Mississippi River.
Summer comes late for bluegills. Jeff Janvrin, Mississippi River habitat specialist for the Wisconsin DNR, says river bluegills in his neck of the woods (primarily Pools 5 through 10 on the Mississippi) begin spawning when water temperatures hit 67°F. Bluegills need to spawn out of the current, so they tend to invade the shallows near wintering habitat in connected lakes, backwaters, reservoirs, and bays away from the main channel. Sometimes they move from connected lakes and ponds into backwaters with better or more extensive spawning habitat, if they can stay out of the flow.
"Bluegills on the Mississippi River are migratory," Janvrin says. "They winter in water 4 feet deep or more in areas out of the current with high oxygen content. Once the water hits about 10°C (50°F) in both fall and spring, river bluegills become very mobile fish. One bluegill marked with a tag moved 7 miles between tagging and recapture. Telemetry studies show fall movements of up to 51â„4 miles between summer and overwintering habitats, so they probably move that far between spring and summer habitats, as well. Most observed spawning beds are near overwintering habitat, but probably not all of them. After spawning, they can cover some water."
Before spawning, river bluegills are highly temperature-sensitive. Active bluegills find the warmest water in a bay or backwater during spring. Even a 1°F difference can be a huge deal before the surface readings top 50°F or so. Locating active fish becomes simple in early spring: Search the shorelines for the warmest water and probe any shoreline wood, emerging weeds, or other cover available in that area. Light-to-moderate breezes stack warm water on windward shorelines, offering substantial clues about starting points. Because river bluegills are more mobile than varieties that inhabit ponds, lakes, and reservoirs year 'round, they won't hesitate to seek warmer water throughout any bay or even throughout a series of backwaters.
Any woodcover within that zone of warmest water becomes a magnet for river 'gills, but the key is warmth, not wood. Wood within the coldest water in the bay tends to hold no fish at all until water temperatures broach 60°F or so. At that point, water temperature begins to become less important as a factor influencing location. Also at that point, weeds become noticeably thicker. For river bluegills, weeds are grocery stores. And soon after that point, bluegills begin to stage near nesting sites.
River backwaters generally provide greater fertility and diversity of forage than lakes in the same area. Fishery biologist Steve Zigler of the U.S. Geological Survey recently studied the relationship between bluegills and weeds in the backwaters of the Mississippi River. "Ironically, our work was in response to vegetation die-off in the backwaters of the Mississippi, due to extremely low water," Zigler says. "Our site was Pool 7, near Onalaska, Wisconsin, a tremendous bluegill fishery through the 1990s. But, along with the vegetation, bluegill numbers declined. We've done a lot of habitat work there in recent years to bring back weeds and wintering areas, which have been gradually silting in since the dams were installed.
"Backwater bluegills eat lots of invertebrates inhabiting vegetation. Even the biggest bluegills feed on them. When bluegills reach a certain size, they strike out into open water in most environments to take advantage of zooplankton. Those fish tend to grow big. In rivers, we're not certain yet how important zooplankton is for 'gills that move into the main river channel in summer."
Steve Gutreuter, a doctor of fishery science also working for the U.S. Geological Survey, explains why some river bluegills leave backwaters in summer: "Along with providing food and shelter from predators, weeds can choke a backwater, causing oxygen depletion at night or when vegetation dies, moving bluegills out to the edges of the main river channel."
By pulling trawls across Pool 10 near Prairie du Chien to sample fish populations, Gutreuter and his colleagues discovered something fascinating: Bluegills were using the main river more than anyone had expected. "The shallowest water we could trawl was about 9 feet deep," he says. "When water levels were below median flow in that pool, large adult bluegills were out in the main river, crowding toward the navigation channel as flows dropped. When the flow was high, they pushed back toward shoreline-related structure. But bluegills were the second'‘most numerous fish sampled in the main channel throughout our entire cycle, including both high- and low-water periods.
"People tend to regard bluegills as lake fish," Gutreuter says. "But they are a relatively recent development in evolutionary terms. The first centrarchid (family that includes bluegills and bass) fossils appear in drainage basins during the Eocene epoch (38 to 54 million years ago). Lakes are very recent, geologically speaking. Centrarchids predate these lakes by millions of years, so I think it's more accurate to think of bluegills as river fish. If you really want to understand bluegills, rivers are the place to start researching them.
"When the vegetation died off dramatically in many of these backwaters, we saw a reduction in bluegill populations. Increases in vegetation seem to coincide with increases in their numbers. Lab experiments showed better growth for bluegills that have access to vegetation. Weeds are really important during that first year, for survival as well as food."
Low-water years can produce huge diurnal swings in oxygen content within backwaters. Aquatic plants photosynthesize during the day, producing oxygen; then they respire, consuming oxygen, at night. "It's a daily swing," Janvrin says. "During early morning, you might have very low oxygen, sometimes 0 counts, due to respiration of plants and animals. By morning, bluegills have moved out to slowly flowing water to capitalize on the higher oxygen content there. But by late afternoon you can have super-saturation in the backwaters due to photosynthesis during the day, bringing bluegills back into the food-rich environs of the backwater.
"In high water, current extends farther into backwater systems, but you can still have diurnal shifts. Bluegills do distribute throughout the backwaters all summer, according to our monitoring data. Sometimes, river bluegills make relatively long daily movements in summer, back and forth."
River backwaters can be extremely fertile places, enriched by a constant supply of nutrients carried in and deposited by floods. In high-water years, some bluegills bury themselves in stands of cane, rushes, and cattails in the fringe areas along the main river, or they find fallen trees and deadheads surrounded by dense thickets of emergent coontail, hydrilla, milfoil, or other aquatic plants.
Immediately after the spawn, when fairly high to average flows dominate, bluegills creep out into the river proper, using the insides of bends where current is reduced, or hiding behind log jams, rockpiles, weedbeds, or boulders for cover. Some slip beneath the main flow of the river, following the downstream side of rock or gravel bars that extend toward mid-channel. Generally these areas have to be adjacent to a backwater or large bay that provides spring or winter habitat, but not always.
Later in summer, they can be found almost anywhere in the system. In extremely low water, they can sometimes be found suspended in the middle of the river, roaming like packs of piranha. The highest densities of bluegills tend to be adjacent to marshy areas thick with cane, rushes, or cattails. But, in extreme low-water years, they can roam upriver, well beyond backwaters. In some cases, backwaters become too shallow, forcing them to spread farther afield in the main river.
As a general rule, a higher percentage of the bluegill population remains in backwater areas during high-water periods, while the opposite occurs during low-water events.
The most overlooked bluegills in flowing systems are main-river fish, yet they're the easiest to approach in summer. I carry a few long, light-action float rods (8 to 11 feet), some rigged with fixed floats, some with slipfloats, some with Ande Premium 4-pound, and some with Maxima Ultragreen 6-pound. These fixed floats are designed for rivers and include the smallest Thill River Masters; but in spring, when bluegills are always shallow, I use Rainbow Plastics A-Just-A-Bubbles. In the main river, classic river floats are easier to control while keeping more line off the water, but sometimes bluegills are deeper than 12 feet. When bulls go deep, I use tall slipfloat designs from Rod-N-Bobb's, Thill, or Northland Tackle, which hold line off the water pretty well.
River bluegills are very familiar with leeches, which thrive in backwaters, especially when connected to wetlands and marshy areas. A small leech on a small jig is perfect whenever the water is above 50°F. Below 50°F, while bluegills are still attached to backwater wintering zones, waxworms, maggots, and various plastics work well. I present all of these options on TC Tackle ballhead jigs ranging from 1/100- to 1/32-ounce. Most of my jigs are black, white, brown, or chartreuse. In rivers, white and black outperform all other colors for me about 80 percent of the time.
In spring I follow the wind, pitching small plastic bubbles or slipfloat rigs into tight areas around fallen trees. Here, slipfloats allow you to throw a more compact package into gaps between branches and logs when bluegills are buried deep. The extreme fertility of backwaters comes into play quite often. Sudden hatches or migrations of invertebrates along bottom or on cover can make a hot rig turn cold quickly, as bluegills transition from opportunistic to selective behavior. Hatches allow you to see this happening, but other migrations do not. Whenever a bite changes, be ready to experiment quickly and efficiently with different colors, baits, and plastics. When bluegills begin to spawn, I generally leave them alone.
In summer, out of the heavy vegetation of the backwaters, floats are the way to go. Float systems cover water and keep baits in sight, slightly above the fish. River bulls can't resist small to large leeches in summer, but they can spread out into a variety of habitats and become difficult to locate. So keep the plan simple. In high water, stay in the backwaters and along the fringes of the main river. In moderate or average flows, hunt for big bluegills along main river banks, on structures like rockpiles, rockbars, and fallen wood that extend into the river from shore, and keep the bait down near bottom. In high to average flows, bluegills using the main river hug current breaks. In that scenario, slipfloats rule, as the bite often occurs at 10 feet or deeper.
In low water, bluegills use the entire water column, and often reveal themselves by boiling on top to avoid your boat or to feed on hatching insects. Find a likely spot — near an inlet, adjacent to a backwater, or anywhere you can spot a few on top — and cover the entire river, from the surface to the bottom and from bank to bank. During low-light periods or during hatches, a 3- to 5-weight flyrod can be the most efficient tool to use.
In the outer reaches of backwaters and along the fringes of the main river where cover is dense, pocket fishing with long telescopic poles is possible, if the boat can reach the best places without becoming mired in weeds. Pitching is possible in the more open areas, too. But in the river channel, float-fishing excels. A river float carries bait or plastics to the fish, picking off the participants farthest upstream, allowing you to work gradually through a school grouped by current. Without current, bluegills are free to spread out, becoming less dependent on structure. In low water, bluegills can inhabit the richest feeding lanes in the river, even out in the middle, and often do.
Low water is accompanied by reduced current. In riverine areas above reservoirs, the current can seem to halt altogether. A float no longer moves downstream, and the river becomes a long pond. In that scenario, bluegills may begin to suspend throughout the water column from bank to bank. They can be everywhere around your boat, yet making contact with them can become difficult. Time to break out the ultralight rod and cover water faster with small Yo-Zuri Snap Beans, similar cranks, or 1/32-ounce jig-grub combos on 2- to 4-pound line.
According to Janvrin, "Bluegills are one of the most popular species among anglers of the Mississippi River." Why not? When they're buried in tangles of wood so thick you lose 6 hooks just thinking about fishing there, real bulls are a true test. In the main river, the little pugilists are pumping iron against the flow, just waiting to sock it to somebody. It can be a long wait, because most of the troops are still marching into the backwaters, looking for the unconquerable Seminoles of the fishing world.