Solution to "What Would You Do?"
Sherlock Holmes Replies:
I picked Sherlock Holmes as the protagonist because he was a master detective and probably would have made a great fly fisher. To solve this puzzle you need his instinct for spotting the details that will lead you to the solution.
To figure out this puzzle you need to have some knowledge of entomology and hatches. Baetis are small swimming mayflies that live and emerge in the riffles. Their time of emergence and the heaviness of the hatch is frequently affected by the weather. The darker the day, the earlier and heavier the hatch tends to be. Therefore Baetis often emerge when the weather is the worst. This particular day was overcast and that made the Baetis hatch earlier than normal.
Secondly, The San Juan is not uniform in terms of its hatches. Different hatches occur on different parts of the river. But more importantly, in this case, the timing of the hatches can be different. In this particular channel, I learned that the midge hatch lasted till later in the day.
These two facts conspired to create the classic masking match. The trout were still keyed on the midges and they had not yet switched over to the early hatching Baetis. I had made the cardinal sin of overconfidence in assuming that the hatch that was obvious to me would be what the trout were feeding on.
I was so sure that they were feeding on the Baetis that I failed to notice that the trout were feeding in the wrong location for the Baetis hatch.
When trout are actively feeding on Baetis they will move up to the optimum feeding lie, which in this case would be at the base of the riffles or in to the riffles. If the trout were taking the Baetis emerger subsurface, they should be right at the foot of the riffles. By the time the Baetis float down to P2, most have already emerged and are duns. Therefore it would be unlikely that the trout would choose this spot to feed subsurface on emerging Baetis.
After the trout rejected my Baetis imitations, I finally noticed this discrepancy. I looked closer at the water and there were still some midges coming off. Now everything made sense. I switched to a clipped Griffith's Gnat, which was refused. I then tried a black body/white winged RS-2 fished in the film which turned out to be the right fly.
The teaching point of this puzzle is not to illustrate a masking hatch so much as it is to demonstrate that the *location* of a rise is often as important as the *type* of rise in determining fly selection.
In my Dry Fly Faq, I spent an entire section on analyzing rise forms but little or no time in discussing rise location. That is because rules of thumb for rise location and what flies to fish is a concept that requires some prior knowledge of entomology.
In teaching beginning fly fishers, I have found that they can readily understand and apply the knowledge that fish will rise differently to an adult caddis fly that can fly off at any moment vs. a spent spinner that is forever trapped in the surface film. But they have a harder time understanding the concept of rise locations because it requires that you know the biology of the different hatches that are present. You need to know where the insects live as nymphs, larvae, or pupae. You need to know when the emergence occurs, how long it takes, and how long and how far the immature emerger can drift as it becomes an adult. You need to know how long the adult stays on the surface before taking off. Consider integrating this information for several hatches and the solution can be complex – a problem for Sherlock Holmes.
I make the analogy to a diner (trout) feeding at a buffet table. Each buffet table represents a different hatch and each buffet table is of a different length. The buffet tables all begin with appetizers (the nymphs/pupae), then the entree (the emergers) and end with desert (the adults) with some scattered soup and salad dishes present (cripples and stillborns). The distributions of the dishes vary for each table (hatch).
All the tables are lined up in a long room (the river) but they begin and end in different locations. You know that the front of the dining room is a riffle, the middle of the room is a run and the end of the room is a pool. All you can see is where and how diner is feeding and you need to decide what he is feeding on.
Well if you knew that the diner fed differently on the entree (emergers) than on the desert (adult) you could narrow your choices down. Now if you knew that the diner fed differently on cake (mayfly duns) than on ice cream (adult caddises), you could narrow your choices further. This is what rise form analysis does for you.
Now if I told you where each table started and stopped, and where the changes from appetizers, to entrees to desert were for each table, you could really narrow your choices. This is what knowledge of the entomology and rise location can do for you.
This is the lesson that Sherlock Holmes taught me that day on the San Juan.
This article is copyrighted. No reproduction by electronic or other means is allowed without permission of the author.
Sherlock Holmes Replies:
I picked Sherlock Holmes as the protagonist because he was a master detective and probably would have made a great fly fisher. To solve this puzzle you need his instinct for spotting the details that will lead you to the solution.
To figure out this puzzle you need to have some knowledge of entomology and hatches. Baetis are small swimming mayflies that live and emerge in the riffles. Their time of emergence and the heaviness of the hatch is frequently affected by the weather. The darker the day, the earlier and heavier the hatch tends to be. Therefore Baetis often emerge when the weather is the worst. This particular day was overcast and that made the Baetis hatch earlier than normal.
Secondly, The San Juan is not uniform in terms of its hatches. Different hatches occur on different parts of the river. But more importantly, in this case, the timing of the hatches can be different. In this particular channel, I learned that the midge hatch lasted till later in the day.
These two facts conspired to create the classic masking match. The trout were still keyed on the midges and they had not yet switched over to the early hatching Baetis. I had made the cardinal sin of overconfidence in assuming that the hatch that was obvious to me would be what the trout were feeding on.
I was so sure that they were feeding on the Baetis that I failed to notice that the trout were feeding in the wrong location for the Baetis hatch.
When trout are actively feeding on Baetis they will move up to the optimum feeding lie, which in this case would be at the base of the riffles or in to the riffles. If the trout were taking the Baetis emerger subsurface, they should be right at the foot of the riffles. By the time the Baetis float down to P2, most have already emerged and are duns. Therefore it would be unlikely that the trout would choose this spot to feed subsurface on emerging Baetis.
After the trout rejected my Baetis imitations, I finally noticed this discrepancy. I looked closer at the water and there were still some midges coming off. Now everything made sense. I switched to a clipped Griffith's Gnat, which was refused. I then tried a black body/white winged RS-2 fished in the film which turned out to be the right fly.
The teaching point of this puzzle is not to illustrate a masking hatch so much as it is to demonstrate that the *location* of a rise is often as important as the *type* of rise in determining fly selection.
In my Dry Fly Faq, I spent an entire section on analyzing rise forms but little or no time in discussing rise location. That is because rules of thumb for rise location and what flies to fish is a concept that requires some prior knowledge of entomology.
In teaching beginning fly fishers, I have found that they can readily understand and apply the knowledge that fish will rise differently to an adult caddis fly that can fly off at any moment vs. a spent spinner that is forever trapped in the surface film. But they have a harder time understanding the concept of rise locations because it requires that you know the biology of the different hatches that are present. You need to know where the insects live as nymphs, larvae, or pupae. You need to know when the emergence occurs, how long it takes, and how long and how far the immature emerger can drift as it becomes an adult. You need to know how long the adult stays on the surface before taking off. Consider integrating this information for several hatches and the solution can be complex – a problem for Sherlock Holmes.
I make the analogy to a diner (trout) feeding at a buffet table. Each buffet table represents a different hatch and each buffet table is of a different length. The buffet tables all begin with appetizers (the nymphs/pupae), then the entree (the emergers) and end with desert (the adults) with some scattered soup and salad dishes present (cripples and stillborns). The distributions of the dishes vary for each table (hatch).
All the tables are lined up in a long room (the river) but they begin and end in different locations. You know that the front of the dining room is a riffle, the middle of the room is a run and the end of the room is a pool. All you can see is where and how diner is feeding and you need to decide what he is feeding on.
Well if you knew that the diner fed differently on the entree (emergers) than on the desert (adult) you could narrow your choices down. Now if you knew that the diner fed differently on cake (mayfly duns) than on ice cream (adult caddises), you could narrow your choices further. This is what rise form analysis does for you.
Now if I told you where each table started and stopped, and where the changes from appetizers, to entrees to desert were for each table, you could really narrow your choices. This is what knowledge of the entomology and rise location can do for you.
This is the lesson that Sherlock Holmes taught me that day on the San Juan.
This article is copyrighted. No reproduction by electronic or other means is allowed without permission of the author.
