The ups and downs of structure fishing

I love structure fishing and have been doing it most of my fishing life. One might say I am a structure fishing junkie. Offshore fishing is as comfortable for me as flipping a dock or slow rolling a spinnerbait down a blowdown. Most anglers actually try to avoid true structure fishing or only spend a short time experimenting with it until their patience wanes and they go back to the bank.

Offshore or structure fishing can be equally daunting for beginners and veteran anglers alike. Let’s qualify a few things first. Structure is what the bottom of the lake does. Cover is what is on the structure. For example, a river ledge is structure; stumps on that ledge are cover. The other thing that must be categorized is the type of water: natural lakes, rivers, reservoirs and river impoundments.

Let’s start with natural lakes. All natural lakes are formed as a result of some natural phenomenon, such as a glacier, earthquake, flood or a volcano. We, as bass fishermen, never really fish lakes formed by volcanoes. Rivers are, well, rivers. About the only differences among rivers are whether they are fast-flowing, slow or tidal. Reservoirs are manmade lakes, involving the damming of a river at one end to form a lake. River impoundments are very similar to reservoirs, except they still maintain their river-type landscape and usually have a dam at both ends.

All bass movement requires structure. From spring to winter, bass use contour lines like we use a road. The whole key is to start out with the seasonal pattern in order to distinguish a depth zone. However, for this blog we will use summer for our season of choice. I am going to give you a brief summary of each of the types of water you may encounter. Just keep in mind if I get to detailed with this blog, it will run for the rest of the season. Don’t despair; there will be plenty to keep your interests offshore until fall.

Natural lakes

We must first make the distinction if the lake is glacial, flat, weed-filled or a combination. Here is a tip on glacial lakes: Find out the direction of the glacier movement (west to east or north to south) this will determine the direction of all the structural elements and make it easier to find bumps (glacier deposits) that are not on any maps.

Our next observation must be water clarity. How clear is the lake? Important note: the clearer the water, the deeper the fish. Next we must find out the forage base of that lake. Water clarity and forage base will be a must for all types of fisheries. Is our forage made up of pelagic shad, alewives, smelt, etc., or bottom-dwellers, such as perch, gobies, darters or crawfish?

If our lake is a weed environment, we will seldom have to fish deeper than the deepest vegetation grows, although you can still catch fish deeper, but this may not be where the highest percentage of bass resides. Look for inside and outside turns on the grass edge or, better yet, rockpiles on the edge of the grass nearest the sharpest break. A natural glacier lake with both options would be a lake like Champlain. This lake offers every type of offshore structure condition.

In a lake such as this, the important thing to do is pick a bass species to target. Here we can find smallmouth and largemouth using the same places this overlap occurs because of the amount of prime habitat. If we want to fish for specific species, we must then go to the extreme ends of each species’ preferred habitat. For smallmouth, look for deep rockpiles or glacier grooves. For largemouth, look for giant shallower grass flats. This extreme separation will lessen the chances to catch both species from the same place.

Rivers

Rivers are by far the most predictable bodies of water to fish. Current is everything! Of course, we will not forget water clarity. Here is a pretty good rule of thumb for our rivers: the faster the current, the shallower the bass. The dirtier the water, the shallower the bass. Structure or cover that offer current breaks are always high-percentage spots.

Slow, meandering river systems that offer backwaters require a little more thought. These systems offer more options in the form of main-river or backwater fishing, as well as deeper structure fishing potential. Again, water clarity is crucial for the deeper option. On most slow systems, I prefer the main river in summer especially if there is a grass option.

Tidal rivers are the easiest to fish, as long as we remember the tide is everything! Always try to fish the outgoing tide, although the incoming tide can be awesome as well. We seldom have to fish deeper than 10 feet. The only exception is in the winter, when bass will migrate to the deepest current breaks, such as creek mouths, in order to spend the coldest months in the most stable of conditions. Oh, by the way, the bass will stack in these areas by the hundreds, but that is winter and we are talking summer. Sorry for the sidetrack, but you have to admit it kind of makes you anxious for winter fishing on tidal rivers.

Reservoirs

Reservoirs are by far the coolest places to structure fish. The type of cover you can find, and the depth it can be located, is simply based on the terrain that was flooded. Some true reservoirs offer a current option, but in most instances current is minimal (but still important). In addition to water clarity and types of forage, now we have another factor to be aware of: thermocline.

The thermocline is where there’s a significant temperature change where dissolved oxygen becomes thin and bass do not like to be below the thermocline. This is important because you will not be fishing below that depth. Oh, here is the good part, the thermocline can be at any depth, usually (but not always) deeper than 25 feet, and the thermocline can be at different depths in different areas of the same lake. Wow! Don’t run yet. Finding the thermocline is not that difficult. Simply turn your locator’s sensitivity up and you will notice a distinguishable fuzzy area, almost like you took a toothbrush and rubbed up and down over a pencil smudge. This will happen at a depth range and will appear to take up 2 to 3 feet. For example, say we find the thermocline 45 feet deep, the fuzzy line on the graph might be 44 to 46 feet deep. So now that we know where the thermocline is and we know what depth the forage is, we can now start looking for structure and cover in that depth range.

River impoundments

River impoundments are awesome to fish. Again, look at water clarity, forage base and, most importantly, current. The best part about structure fishing river impoundments is river ledges, and there will be miles of them. What I like to do first is to find the biggest flats —the bigger the flat, the more bass. That being said, the possibility of secondary creek channels expands exponentially. Now you are formulating a picture on what to look for. Ledges and creek channels have certain characteristics that I target. First, I look for turns and bends; next I look for junctions where two or more channels converge (funnels). Then I search out specifics such as rock, wood, manmade structure or grass.

The key to remember with current is that it always sparks feeding. Everyone knows the down-current side of structure holds a current break; however, so does the up-current side, although not as large of an area. This is important because there are times when largemouth use this current seem as a form of cover and restaurant. Some of the biggest smallmouth I catch come from the up-current side of things, so do not overlook this.

So far we have digested a ton of information. For some basics on lures for fishing deep, here is what I like: big deep-diving crankbaits, Carolina rigs, football jigs, drop shot rigs, vertical spoons and big flutter spoons for a horizontal presentation. Do not make color choices complicated; for cranks, all you need are a few natural shad patterns and some hot color patterns. For soft plastics, just try to match the water color or bottom color. Same goes for football jigs, tubes and drop shots. Spoons are the easiest —silver, gold or white.

When I fish offshore, I idle around for hours looking with my Humminbird locator/side image system. I look for the sweet spot on the structure, mark it in my GPS and, when I have a bunch of places, I will then go back later that day or the next day and start fishing them. One key to remember when fishing structure is this: Change your angle of presentation when fishing. I have noticed that the fish will definitely prefer one casting angle over another. You must remember this; it will be the key to catching or not.

Break out of the ordinary and head offshore —it could open new fishing opportunities on your old fishing hole. Good luck in your offshore adventures.

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