In the situation that became the impetus for this article, I was fishing the mid-section of DePuy’s spring creek in Montana’s Paradise Valley. It was the time of the Pale Morning Dun mayflies, and I was casting across-current to fish that were working a lane along a row of weed clumps. After watching for a little while, I could make out a wavering olive-red slash in the water, perhaps 35 feet from me. “No problem,” I thought. “And I get to watch him take it.”
A dozen or so casts later it was time for a reassessment of that particular train of thought. I checked the fly—an emerging nymph—looking for any detritus that might have accumulated on the hook. It was clean. I knew that I had gotten a number of drag-free passes over what I thought was the fish’s position, and since he was continuing to feed, I knew that I hadn’t spooked him.
As I watched, my eye picked up the yellow pinpoint of a freshly emerged dun fluttering in another current on the far side of the fish. The dun slid along the edge of a weed clump and then made a surprise turn toward the fish’s position. In a moment the dun had been transported across the currents at the backside of the weed clump and in toward the lane where I had been casting. The fish ate the dun at about the same time the light bulb went on in my head. The trout was not actually working the more obvious feeding lane. No, the fish was parked in a neat little holding position at the edge of the lane, watching for insects coming across the hidden lane behind that weed clump.
My next cast put the fly in a new position—the far side of the weed clump. I just needed a few seconds of extra drift. Just as I was about to lift the line to re-cast, the fish rose. The hook set was immediate and the fish was off and running. A couple of minutes later, I slipped the 16-inch rainbow back into the current and began cleaning weeds off the knots in my leader. A 16-inch rainbow is no great prize on DePuy’s, but solving the puzzle of the hidden lane made that fish one to remember.
Although serendipity can certainly play a part in locating hidden lanes, there are some things you can look for to help discern water/food flow. Watching objects on the water’s surface—in the case above, a mayfly dun—can tell you not only where a hidden lane might be, but also how to make the necessary cast. It also pays to spend some time assessing the bottom (if you can see it) and visible weed growth. A bottom with sudden elevation changes (a sharp ridge or deep pocket for instance) can alter water speed and direction. A staggered row of weed clumps or a single large clump that has a slot through it may also indicate that currents are moving in previously unsuspected ways.
A fish feeding consistently at the fringe on a known lane—particularly if you suspect a hidden lane—can be a tip to look more closely. In my little story above, the fish was holding quite steady in his position, even while other fish drifted back and forth in the known lane. As it turned out, the fish was parked at the confluence of the hidden and known lanes, right where he could take advantage of certain hydraulic pressures. All I had to do was put the fly in the right spot one time and the fish took immediately.