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San Juan Strategies: 5 Tips for Tough Days

Updated: Oct 14, 2022

Fall fishing on the San Juan is one of my favorite times to guide, but it can also be incredibly technical. I wanted to write this blog to share my favorite tips for when it feels like you can't get a read on where the fish are and what they're eating.

Fall fishing can be all over the map. Flows are changing depending on irrigation needs, and air temps are fluctuating wildly throughout the day and season. Both water flow and air temperature impact where the trout can hold as well as affect bug activity. With more water, there are more spots for the fish to spread out and settle into. The inverse is also true. Flow changes, rain, and lake turn-over can stain the water making it difficult to figure out where in the water column the trout are feeding.

If you've ever shared a day in the boat with me or heard my presentation, I often preach a "trout first approach". I like to think about the fish's biological needs and how they react to outside factors before making rig adjustments. The trout of the San Juan River are notorious for getting "column locked" and having your depth and weight even slightly off is the difference between a tough day and a great one. Throughout the day consider where in the water column the trout are feeding. Think about the various life cycles of midges and mayflies and how trout will feed on their different life stages at different times throughout the day.

While trout will eat midge larva all day, I prefer to fish them early in the morning when there are less pupa and adults around or I'll fish them in between hatches. Midge larva are found in the lower 1/3 of the water column. That will give you an insight on how to rig. The lower 1/3 of the water column could mean you're fishing 1 foot down or even 8 feet down. It's all relative to the water in front of you.

Be flexible. There are no magic formulas or silver bullets.

1) Fish With Your Eyes First

It sounds cliche but it's very true. Before you even begin to rig or think about flies, fish with your eyes first. What do you see? Can you even see fish? Where are the fish holding in the water column?

Before rigging I make sure to scan the water I'm about to fish. If I notice fish feeding at a particular depth, I will rig to that depth. If I don't see fish or the clarity is bad, I try to look for rising fish (heads) or fish eating just under the surface (backs and tails). I especially try to locate fish whose heads are coming up when I have clients that want to fish dry flies. It's a great way to single out fish willing to eat off the surface even amongst a pod of fish eating midge pupa and mayfly emergers.

If you've ever seen fish whose tails and backs are poking up, that's what we refer to as "midging" fish or fish eating mayfly emergers.

More often than not, a double indicator rig is what I use to feed fish eating in the first two feet of the water column.

2) Work Top Down

To put it simply, fish lighter split shot than you think. Trout will more often than not tilt their heads up to eat rather than nose down. In my experience, I'd rather be slightly over trout with my flies versus under them. Usually I'll probe an area with lighter "mid column rigs" first. If I'm light enough, the flies will stall in the upper column and finally suspend mid column. It's a two for one. If fish are eating later in the drift, I know that I can bump weight to get my flies down quicker. If the eats are earlier in the drift, I'll choke up on the indicator or fish lighter split shot. If I get no eats, I'll deepen up and/or go heavier.

"Choking" the rig up 2 feet shallower was what was needed to put this fish in the bag for Brett.

3) Downsize Indicators

I try to fish the most sensitive or the smallest indicators I can get away with relative to the weight load. A lot of my friends like to fish yarn. For me I like micro Corqs, Fullingmill pinch ons, air-locks, and oros. For the record, yarn is great; I'm just set in my ways. I can't tell you how many times I float by wade anglers fishing golf ball size indicators and I can't imagine how many eats they're not seeing register on the strike indicator. The fish on the San Juan are notoriously light eater. You need to stack the deck in your favor.

4) Don't be a Martyr

You've heard the old adage "don't leave fish to go find fish", but in my mind that only applies if you're getting them. It's okay to leave. Generally if I can't get them eating after 3 adjustments, I move. Trying to find dumber fish or fish that are actually on a feed cycle vs sulking is okay. The "stick and move" approach has turned countless slower days into very successful ones.

5) Hand Grenade Approach

Sometimes the fish are lock jaw, not feeding, or just keyed into a very particular size of bug or profile. In these times I hit them with a "grenade". There are two types of eats in trout fishing: fish eating and induced takes. Trout will mouth foreign objects because they're curious vs actually eating them. This is the time to throw a wild "trash rig". Trash is guide slang for worms, eggs, mops, leeches, and any other obnoxious or gaudy fly. This strategy has saved many a day for me on the ole San Juan.

Consider this, if you live by trash rigs you'll die by them. There's a time and place to fish junk and when the trout aren't into it you'll know right away. Don't grind out the rigs if the fish aren't having it (see tip 3).

Hopefully these tips will work for you next time you're having a rough go at the San Juan. I continually reflect on these points throughout the day and am always making micro adjustments with my presentations or the water I'm guiding. These are not gospel, nor am I claiming them to be so. There is no always or never in fly fishing and I'm constantly blown away by the amount of times I've seen everything go wrong and fish still get hooked.

Remember to be flexible, take time to observe, make adjustments, and most importantly, have fun.

- James

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