Presentation- Your presentation will solely depend on the water temperature. The water temperature will tell you how fast to strip the fly, whether topwater is an option, the food item you wish to represent, the size of your fly, and the depth at which to fish. Let’s start with water under 50 degrees F.
Dredging- When the water is cold (under 50 degress F) fishing the bottom is the best option, and you need to get close (I would guess two of three feet from to the fish). There is only one effective way to do this. You will need a fast sinking line. There are full sink lines with a variety of sink rates. I would start with something around 6 inches per second. Casting distance in this situation doesn’t really matter as the line eventually ends up under you boat (this technique is not possible for wade or shore angling). There also needs to be additional weight at the the end of the line to create a tight connection. This can come in the form of a brass bead or heavily weighted fly. Make a short cast between 10- 20 feet and feather out the adequate amount of line to reach the bottom by shaking the rod tip. Once you have established contact with the bottom or you know that your fly is close to the bottom (read the sink angle of the fly line) you can start to strip. Strip in 10-15 feet of line and then feather out the same 10- 15 feet and let the fly sink again. The drift of the boat will determine the area of water that you will cover. I have deployed this method very effectively fishing deep in the ocean (targeting founder and rockfish) as well. Tip- I like to cut 30 feet of sinking line and loop it to a floating running line (this can be a standard WF line). Knowing when exactly 30 feet of line is out plus however long your head is on your floating line will eliminate much of the guess work.
Slow subsurface- This is an effective technique three quarters of the year, and is a nice technique when targeting suspended fish. The bass will start chasing moving baits when the water is above 50 degrees F. The target depth is here is between 1-20 feet below the surface of the water. You can use a sink tip or weighted flies to reach the target depth. The strips should be slow and methodical with ample time in between strips to let the fly sink. Often the grabs are when the fly is sinking. Also, around this water temp the angler will begin to use the shore line to determine the direction of casting. Understanding where the drop off (The transition between deep and shallow water relative to the shoreline) is important. You will need to work your casting angles. The first cast can be 90 degrees (casting directly at the shore) and you can work you fly over the drop off, and you next cast should be a few degrees less until you are casting parallel to the shore. The next searching technique would be position your boat further back from the shore. The deeper the water gets, the slower you should strip and wait between strips. You don’t need to get the fly exactly at the same depth of the fish. They will swim up (I would say 5 to 10 feet above the fish is ideal) to take the fly if presented well. Tip- You can fish two flies effectively with this method. When conventional anglers fish two flukes they call it the ‘donkey rig’, but I don’t think there is an official name of this setup for fly fishing.
Float and Fly- This technique is popular in Northern California for spotted bass, but does work will for largemouths too. I like to use this method in the early spring when the water temp is just starting to creep over 50 degrees F. Float and fly utilizes a strike indicator and is designed to keep a fly at a precise depth. I would say 10-15 feet deep is ideal, but you could run a rig that fishes 20-25 feet. You will need flies tied on jig hooks. Slow short strips can give the fly action and allow the angler to cover water. A little chop on the water can also provide good action for the fly. Tip- this is a nice multi species method. Bluegill in particular will aggressively peck at a small jig.
Topwater- Everyone’s favorite way to bass fish! The water temps need to be in the high 50’s, but ideally above 60 degrees F. Here the fly can disturb the surface of the water, and the bass will expose themselves to take the fly (creating an exciting ‘blowup’ on the surface of the water). The key point to this is structure. There needs to be plenty of subsurface structure for example rocks, wood, weeds, laydowns, brush, or manmade structure for an effective topwater presentation. Open water (flat bottom off shore) is usually difficult. It can be done with bass are feeding on schools of baitfish, but that’s a lot of chasing and waiting. You will need a fast boat. When the bass are holding to structure they feel safe. Work your fly around structure (the shoreline counts). Casting accuracy is so beneficial for topwater fishing. The initial ‘plop’ is where the fishing begins. Don’t start stripping right away. Allow time for the fly to settle, and your initial strips should be slow. The longer the fly is in the right zone (near the structure where the fish is holding) the greater chances of success. If you know the fish are there and they won’t hit topwater, try fishing just below (a few inches) or a fly that doesn’t make such a commotion. This is often the case in heavily pressured areas. Tip- Start with a simple bait fish pattern (walking style) before going to the frog, but if you are keen on frogging; try something a little more subtle in size.
Big Baits- Big baits have certainly caught on in conventional bass fishing, and can be utilized in fly fishing as well. Again, you are looking for water above 50 degrees F. The movement of the fly is important here. It needs to be able to change direction. A straight retrieve is not ideal. A slow ‘S’ or ‘C’ action is what you are going for. It was never be as pronounced as a lure, but you can make up for that with casting distance and accuracy. It is easy to cast a big (8 inches or more) fly with modern shooting heads and fast action rods. Fishing structure is important here too, but you can also utilize depth. You can swim a big pattern over 20 feet of water, and bass will swim up to for an inspection. The hits can be slow though, and bass will hit the side (or head) of the fly. It is easy for them to swipe and miss. That is why conventional lures have two or three treble hooks, and often the fish is hooked outside of the face. Tip- There are going to be more follows than hits. You can also understand how aggressive the fish are. On average I would say the fish that hit a big fly will be larger, but it doesn’t necessarily mean you catch the biggest fish in the area.
Dragging- This is a top water method that comes into play when the water temp reaches above 70 degrees F. This is usually around early summer and the aquatic vegetation begins to grow. You will find patches of lilly pads and milfoil create mats. The drag requires a fly tied weedless (the best designs are on an EWG worm hook) and a short stout leader (10-15 lb mono). The action of the fly is limited, so work the fly slowly of likely areas letting the fly fall through the vegetation once and while. The blowups are exciting. Landing the fish can be tricky though. The hook set needs to be a strip strike, and avoid drawing the rod straight up during the fight. The fish often gets tangled in the vegetation and you will need to keep tension and pull the fish through the mat. Tip- Be warned. Fly rods are not designed for this kind of fishing and will break if you are not careful. Avoid putting too much flex in the rod. You also may hook up with a snakehead (they live under the mats during the summer). If this happens; point the rod directly at the fish and strip as hard and fast as possible. You want to control the head until the fish is in open water. If you allow a snakehead slack they will twist you up and your gear will fail. Either the hook will bend, the knot will break, or your rod will snap like a twig. You have been warned.
In summary- fly fishing for bass is exciting and challenging, and every month will open up new techniques. During the dog days (water temps reach 80 degrees F) you might have to go back to fishing deep. Better yet find the method you enjoy the most and plan your fishing trips around the conditions that best suit you.