Finding Trout: The Undercut Bank - The Fisherman

Finding Trout: The Undercut Bank

2018 4 The Undercut Bank Catch
This fine brook trout was pulled from the protection of its cutout lair where the stream dug several feet into the bank providing an excellent ambush point.

It is the nature of running water responding to gravity to follow the easiest downward-sloping path. In the course of this natural event streams carve their way downhill around bends, rocks and falls altering the stream banks. The shores of such rivers commonly develop erosion in the flow portions while failing to touch the above water ground. A shelf develops above while the wet part drifts downstream; hence, the undercut bank.

These washouts provide overhead cover where current is the strongest, providing a safe haven for feeding gamefish to hide in without concern for predation from above. Nothing can see them, including you. However, if you know enough about the mechanics of river flow, you know that all that disappearing current is deep enough, fast enough and safe enough to hide gamefish.

The Drift

Our rule is that if you can’t see a stretch of water, you can pretty much plan that something is hiding under there. Such undercut banks are made by strong flow deep enough to hold fish while providing overhead protection. If you drift a bait or lure naturally at the speed of the water flow, your offer should slide past gamefish facing upstream. We have done well drifting egg sacks, nymphs and worms in this manner. With most baits we like to add enough split shot for the offer to be bouncing along the bottom. You don’t want to slide anything under the bank that floats because hits are more likely along the bottom than on the flow’s surface.

Because this is blind fishing, you are not going to see the flash of a taking fish; it’s all happening under the bank. That said, you can get some sense of a take if your line stops while drifting in the current. If you happen to feel the take, set up right away because some trout or salmon might spit the offer out. Sometimes they come back on the next drift, but you can’t be sure that you haven’t stuck the buggah with the hook point. Any second chance you get is a bonus. Remember that there can be more than one target hiding in that dark cavern.

Pet Undercuts

Some of the examples in this article are from 20 seasons of Lake Ontario tributary streams, but this stuff all works on put-and-take trout fishing in local streams. River sharpies all know the best hidey-holes of a stream, and because the fish do most of their upstream migrating during the night, the first person walking the river banks in the morning gets to pick the most promising spots. It can be a race at sunrise. Usually the largest washout holds the most salmonids so those are the ones you should get to first. I have seen steelhead stacked in the nicer undercuts.

2018 4 The Undercut Bank Stream
This small New England stream is dotted with an array of trout-holding structure including ripples, pools and undercut banks. (Photo by Toby Lapinski)

Late spring in upstate New York, on a small steelhead river with big steelhead, the run of fish gets hot and heavy. My wife and I have a spot where the fish stop to rest. We can’t see them, but we have been going there enough years to be certain that a fresh charge of night travelers is partying heavily. One time I put my wife there, and she slid her egg sack under the dark shadows until the line stopped. She hauled back on the take but couldn’t get the fish to come out in the open. It just kept fighting in the dark hole until her line broke. Yikes. Then she re-rigged with another sack and the same thing happened all over again: the hookup, the fight, the broken line. At that point, she was biting her lower lip. Inasmuch as she wanted to be left alone, I went downstream where I hoped there would be no steelhead.

That night I put about 80 feet of 20-pound test line on her reel in anticipation of going to the same spot the next morning. Nothing in freshwater can break 20-pound line. She was loaded for bear! This time when her egg sack went under the bank, and a steelhead munched it, she set with a bluefish-like vengeance that sent a clear message about who was boss. It was a 16-pound rainbow from Lake Ontario carrying a white flag. We let it go, but the point was made. It was all about winning.

2018 4 The Undercut Bank Fishing
While the author perfected the tactic of fishing undercut banks for trout in the tributaries of Lake Ontario, they work equally well here in New England. (Photo by John Hanecak)

Watch the River

We have pretty much covered the places on a river where you cannot see. Nevertheless, a lot of times stream-running gamefish will stop off to rest in the open. Nature provides trout and salmon with a lot of camo that can make them difficult to see. All those spots on their flanks look like the pebbles on the bottom. Their dark backs blend in so well that you can walk right past them without noticing they are there. Migrating fish will also choose the deeper runs for resting so watch for places where they can be on the bottom.

No one fishing during daylight should ever be without polarized glasses—not sunglasses because these do not penetrate the surface glare of a water surface. Polarized glasses enable the observer to see clear to the bottom making fish spotting a simple effort. It helps a lot to know where the fish are holding in a river. If you become intimate with a stream, you will learn the places that are popular with the fish. Not only will you see, but you will know where to look. (A lifetime of striper fishing makes me love fishing in the daytime.)

One element that gives the fish away is their shadow on the bottom. I have found sea-run browns (when we had them), steelhead and salmon by spotting a shadow projection under the fish. All that camouflage is of no use if their shadow is easily visible. Be conscious of your own shadow as that dark movement seen by a species commonly predated upon from above will send them hell west and crooked in terror. Fish often do dumb things, but they can also be mighty smart. Know how to look to play the game.

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