During the dog days of summer, fish often hold deep in still waters, avoiding the warmer, less oxygenated shoreline water and venturing into the shallows to feed only very early or late in the day. Most of the time, the fish suspend near the thermocline. During the summer, in large lakes and reservoirs at least 35 feet deep, the water stratifies into three distinct layers. The topmost layer, the layer with the warmest water, is known as the epilimnion, and the bottom layer of coolest water is called the hypolimnion. In between is a middle layer of cooler water, the metalimnion, usually referred to as the thermocline. The fish seek cool water, but sunlight barely penetrates the hypolimnion, and very little photosynthesis takes place there, so it is low in oxygen, and aquatic organisms further deplete the oxygen levels. Consequently, fish prefer to hang out in the thermocline, since it is the coolest layer that has a high level of dissolved oxygen.
That’s often too deep to be reachable by standard fly-fishing methods. If the fish are holding more than 15 feet deep, a standard floating line and leader won’t get your fly deep enough. There are three basic methods I use for targeting deeper fish: using a fast-sinking line, using an intermediate line with a weighted fly, and using a floating line with a deep-water indicator setup and weighted fly.
Fast-Sinking Lines
For fishing deep water in lakes, a full sinking line (not a sink tip) allows you to get the fly as deep as the line can sink. Sinking lines are rated by “type,” most commonly, Type I through VI, which indicate sink rate. For example, a Type III line sinks uniformly at approximately 3 inches per second and a type V line sinks about 5 inches per second. With a heavily weighted fly, though, you can accelerate the sink rate. For example, a Clouser Minnow with heavy dumbbell eyes might sink at a rate of a foot per second, taking the line down with it at a faster pace.
The standard rule for leader length used with sinking lines is the faster the sink rate, the shorter the leader, because it is the line that sinks the fly. I adhere to this rule when fishing rivers with heavy current, but for fishing deep in lakes, I prefer to use heavily weighted flies and longer leaders, even for Type V or VI lines. I go with the longest tapered fluorocarbon leader and tippet I can comfortably cast for a given fly pattern — typically a 9-foot-total leader length for heavily weighted or bulky baitfish patterns, and around a 12-foot length for lightly weighted streamers. Crystal-clear water dictates this leader choice, distancing the line from the fly.
The countdown method works well for full sinking lines. Do the math and calculate how many seconds it will take your line to sink one foot, then count it down, “one-one-thousand, two-one-thousand,” and so on, until you’ve reached the preferred depth. Remember, a heavily weighted fly will sink the line even faster.
Larry Kurosaki is a still water fly fisher who has specialized in fly fishing for largemouth bass at Southern California’s Lake Casitas and Castaic Lake since the 1970s. He’s had great success over the years using a sinking line and primarily just one pattern — Larry’s Minnow, a streamer he developed to mimic the shad that big bass love to feast on. The unique characteristic to Larry’s Minnow is its neutral buoyancy. When paused during the retrieve, the fly doesn’t dive or dip, the way weighted baitfish patterns do, thus more closely mimicking the natural swimming motion of a real baitfish. In 2009, Larry used his namesake fly to land one of the heaviest largemouth bass ever caught while fly fishing — a 16-pound, 12-ounce lunker from the Castaic Lagoon, which is the current 8-pound tippet class International Game Fish Association world record for largemouth bass. Kurosaki’s setup is a bit unconventional. He typically uses a 9-foot 7-weight rod matched with a 30-foot length of T8 shooting head, which sinks about 6 inches per second, combined with 200 feet of 15-pound Amnesia running line on top of 30-pound backing. Fishing from a boat, with this line, Larry can cast up to 140 feet. Then he counts down to the depth at which he wants to fish. For Casitas’s ultraclear water, Larry uses a long leader, anywhere from 12 to 14 feet. He starts with an 8-pound 9-foot tapered mono leader, then adds another 3 to 5 feet of 6-pound mono tippet. While Larry specifically targets bass, some version of this technique is equally effective for trout in deep lakes and reservoirs. I’ve had good success with a Type V full sinking line with an integrated running line. It’s a 300-grain weight-forward line with a shooting head that sinks at about 5 inches per second. When fishing from a boat, I use a stripping basket to help shoot the line without tangles.
The key to great bass fishing on big Southern California reservoirs is locating schools of shad. I scan the water and look for birds and nervous water. Hunted by terns, ospreys, grebes, and pelicans from above and by marauding gangs of bass from below, the shad schools hold deep most of the time, but they make sporadic and sometimes brief appearances, breaking the surface in shimmering bursts. You won’t encounter this too often, but when you do, you need a fast-sinking line to get your presentation down as quickly as possible below the school. Cast a shad imitation into the melee, but let it sink down where the big bass are lurking, then strip erratically to mimic a wounded baitfish. The strikes are ferocious.
Most of the time, though, you’ll need to find deep-water bass by targeting likely holding structure. In California’s big, steep-walled reservoirs, analyze the terrain and follow the ridge lines as they plunge into the depths. By anchoring your boat at the tip of a point, you can cast out, let your line sink, then follow the contour of the terrain as you strip up the side of the underwater ridge where bass often suspend. If the bass are not found near lake drop-offs and points, fish-finding sonar is indispensable for finding what depth the fish are suspending in open water. Then the countdown method comes into play.
When fish are suspended 50 feet deep or more, Kurosaki often resorts to using two rods, which is legal with a two-rod stamp on your fishing license, casting one line and letting it sink, casting another rod, then stripping in the first line while the second line is sinking. The only problem with this, Larry laughs, “is that I often hook two fish, so I decide which one is the bigger fish and bring that one in while the other fish swims around.”
At Southern California’s Diamond Valley Reservoir, which reaches a depth of over 500 feet, fly anglers have developed specialized trolling techniques to target the big striped bass that often hold 40 or 50 feet deep in the summer months. The technique uses a length of lead-core line attached to the front end of a full-sinking Type VI line fished with all the fly line plus 50 feet of backing outside the reel, trolled slowly or fished from a drifting boat. The fly is typically a small white streamer or shad imitation, manipulated by constantly stripping, then releasing the line to create a darting action on the fly. When targeting stripers, it’s not uncommon for this technique to catch largemouth bass and trout, too.
Intermediate Lines
The line I use most often for deep-water lake fishing is a Type I clear monofilament intermediate line. I like a clear line, because I find it stealthier for stalking trout in ultraclear water. It sinks at about 1.25 inches per second. Using just this one line, I can effectively fish from right under the surface down to about 30 feet deep. The advantage of the intermediate line’s slow sink rate is that it gives you better control over the depth at which you’re fishing. For example, if you’re fishing over the top of a submerged weed bed that’s 20 feet deep, you have plenty of time to count down to exactly the proper depth, then begin stripping. If you get snagged or find weed or detritus on your fly, you can shorten your countdown accordingly on the next cast. The slow sink rate also keeps the fly at the preferred depth longer as you strip it in, especially with a slow retrieve, compared with a fast-sinking line.
When fishing from a float tube, I use the intermediate line with a 9-foot tapered fluorocarbon leader matched with a 3-foot fluorocarbon tippet and a weighted fly for deep, slow trolling. I can troll effectively up to about 30 feet deep. I have a small fish finder mounted on my float tube that allows me not only to see where the fish are, but how deep the bottom is and to locate underwater mounds, ridges, weed beds, rock piles, and drop-offs. To set up the troll, I start by making a short cast, then strip out line to create slack while the fly sinks. Once I’ve counted down to reach the proper depth, I begin a slow kick with my swim fins until I feel the line tighten and feel the weight of the fly. To fish from about 15 to 20 feet deep, I normally use a weighted Woolly Bugger (weighted with 20 wraps of .020inch wire) with a marabou tail, slowly kicking with my fins, twitching the fly constantly with my stripping hand, which elicits an enticing, up-and-down wiggling action on the fly’s tail. In windy conditions, when you’re getting blown at a good clip, no kicking is required. Using this technique with a weighted size 10 black Woolly Bugger, I’ve caught trout, bass, bluegills, redear sunfish, crappies, Sacramento perch, catfish, and carp. If I want to go even deeper, up to 30 feet deep, I use a more heavily weighted size 10 streamer with 3/16-inch diameter dumbbell eyes or a size 8 or 10 Balanced Leech with a 3.8-millimeter tungsten bead head.
The Deep-Water Indicator Method
When I was a kid, my first experience with stillwater fishing was using a worm suspended under a clip-on red-and-white plastic bobber at Little Virginia Lake in the eastern Sierra. I’ve “matured” as a fly fisher, but I still love to see a bobber plunge under the surface. Of course, now I refer to it as a “strike indicator.” Staring at a strike indicator all day long drives some fly fishers crazy, but if your indicator is going under on a regular basis, it can be one of the most enjoyable forms of fly fishing.
Mammoth Lakes guide Harry Blackburn is widely credited for developing the Crowley midging technique using a floating line and a strike indicator to suspend one or two chironomid patterns. It’s become so popular that almost every guide on Crowley has adopted it for boat fishing, and it’s so simple that novices easily catch fish with minimal instruction after their guide casts for them and hands them the rod. The key is to watch the indicator (tough with beautiful scenery all around), and when it goes down, act quickly by raising the rod tip straight up. It sounds simple, but there are a few subtleties that aid in increased hookups.
If fishing chironomid imitations with light tippet, it’s best not to hold the fly line, but to get the line tight to the reel with a light drag setting. That way, you can aggressively raise the rod to set the hook without risking a break-off if a heavy fish has taken the fly while moving away from you.
To fish deeper than the length of your rod, you need to use a releasable indicator, because with a fixed indicator placed any distance longer than the distance from your fly to your rod’s tip, the indicator will hit the rod’s tip top and make it difficult, if not impossible, to land the fish, especially if you’re by yourself.
There are many releasable indicators on the market, but the basic design is a simple, yet ingenious innovation. The bobber consists of a foam float with a hole through its length and a small, hollow, tapered plastic peg that pins the line into the float. To rig it, you start by running the leader through the hole in the float and the hole in the peg. Form a small loop in the line, pin it with the peg back into the float, and the rig is ready for action. When you get a strike and tension is applied to the line, the peg pops out of the float, and the peg and float are now free to slide along the line. Don’t pin the loop into the float too tightly, though, since it might not pop out when you hook a small fish. It’s easy to test it before you deploy it by pulling on the leader from above and below the indicator to see how easily the peg pops out.
For a deep-water indicator leader, a non-tapered leader works best. I prefer fluorocarbon for the entire leader, because it sinks a bit faster than nylon and has less stretch. For the upper part of the leader, 30-pound-test braid also works well, since it has virtually no stretch, which aids in long-distance hook sets.
I start with about a foot of 20-pound fluorocarbon, then a length of 6-pound to 12-pound fluorocarbon, depending on the fish I’m targeting — 6-pound for small trout and panfish and 12-pound for larger trout, bass, and catfish. The length varies depending on how deep I’m fishing. Then I attach a tippet ring or barrel swivel to which I tie a final section of tippet with a length no longer than my 9-foot rod. This also prevents you from losing the peg if you break-off at your tippet.
The key to the releasable indicator leader is to not have any bulky knots for the float or peg to get hung up on all the way down to the tippet ring or barrel swivel. Sometimes I just use one section of level fluorocarbon for the entire leader all the way down to the fly after the short butt section for an ultrastealthy presentation.
With leaders longer than 15 feet and a heavily weighted fly, casting the rig is nearly impossible. From my float tube, I’ve found the best way to manage the setup is to take the fly and place it on a Velcro patch on my vest, then measure the length of leader I want to fish and set the indicator. To “cast,” I hold the fly in my thumb and forefinger, then toss it like a dart. Then I just maneuver into position with the indicator where I want it. For long-distance hook sets, it’s best not to have too much fly line out.
The deep-water indicator method works great with heavily weighted flies. My go-to patterns for trout, bass, and panfish are the Balanced Baitfish, Balanced Leech, and Balanced Bugger, tied on size 10 or size 12 jig-style hooks with either 90-degree or 60-degree bends. For a size 10 hook, a 5/32-inch (3.8-millimeter) slotted tungsten bead head balances the fly well and sinks like a stone.
Windy conditions with some surface chop are ideal, because the small waves bob the indicator and impart an alluring action on the fly. Windy conditions also put the fish at ease, because sunlight penetrates the water less strongly. In calm conditions, I move and twitch the indicator constantly to move the fly seductively. In really windy conditions, with a lightly weighted fly, adding a split shot at the end of leader helps keep a tighter connection to the fly, which is better for both strike detection and hook sets.
In mud-bottomed lakes, if you want to fish right off the bottom, which is recommended for chironomid patterns (much of their life is spent in the mud), you can measure the depth by attaching your indicator, then clamping your forceps to the fly and letting it sink to the bottom. See where your indicator ends up and adjust it accordingly. However, in lakes with submerged aquatic vegetation and brush, I’ve lost my forceps this way more than once, so it’s best to attach a small, expendable weight instead.
Using the deep-water indicator method, I caught a four-pound largemouth at a depth of 25 feet from Lake Perris. It was the deepest fish I’ve caught that way. It hit so hard it set the hook before I could even react. When I raised my rod tip, the line was already peeling off the reel. Game on.
Rigging a Releasable Indicator
