'Triggers'

[Silver Creek]

Wow! Tough post to follow but here goes. If a 'trigger' is something about the fly that entices a fish to eat it ....I challenge anyone to tie a fly that catchers fish and doesn't have a trigger.

Trigger is used in the context of selective feeding. I should have made that more clear.

When trout are sampling the drift, they try all sorts of things as the poster that referred to cigarette butts noted. They hit thingamabobbers, they hit floating leaves, etc.

Selective feeding implies that the fish MUST be selective to something about the fly or the presentation. Sampling feeding means they are just sampling the drift so there is no specific "trigger" other that the item happens to be in the drift.

If what I posted is true, then it also must be true that when we fly fish, we are sampling the trout. We are sampling the trout for those trout that are susceptible to the fly and techniques we are using.

Have you ever been in the situation where you caught a number of trout with a particular fly or technique and then that fly stopped working and the other feeding fish refused the fly? What has happened is that you have sampled and caught the fish that were susceptible to your fly but the other fish were feeding on another food item or the same food item that is at another sage of emergence. You have just proved biologic diversity of feeding behavior.

Fly fishing is a method of sampling the fish and we hope that method of sampling matches what the fish is susceptible to. It is no different than using a magnet to pick out the objects that contain iron from a box of items. So we should not be surprised when one fly works and another fly does not. That is why we carry various flies.

Fish can also change their behavior based on what has happened to them while feeding. This is the negative behavior modification of operant conditioning. Recall that selective behavior is the result of the fish being rewarded by food when it eats a particular item so it become operant conditioned to eat that item. This is selectivity.

They can also become selective in the opposite sense in that they will refuse an item that give them negative feedback such as being caught by a particular appearing or acting fly. This is why they refuse a fly that is dragging. They can also become selective in the negative sense that they will refuse particular flies. We experience this type of behavior when a fly that has worked well becomes the "magic" fly on a river and then over a season it stops working. This is negative operant conditioning in action. The fish will ignore this fly because they have been caught with it with negative consequences. This is another reason I will carry several types of dry fly patterns of the same hatch.

I have been in a situation on the San Juan River when the fish were so selective they fed only on a subset of BWO duns. I was fishing with some friends and was called over by one of them who was casting to a pod of feeding rainbows in slow water. He had casted to these fish and not been able to catch a single one so he called me over to try. I asked him to cast again and I could not see any problem with his presentation. There was no drag. The fish just refused the fly.

We could see that the rainbows were taking mature duns. The fish had refused both his comparaduns and parachutes. I had some no hackles and put one on and the fish took the fly.

Then I caught a few more but there were fish in the pod that refused the no hackle and yet I could see that they were taking duns. Why did these fish refuse?

I stopped casting and looked a bit closer and I finally noticed that these fish refused the duns with perfectly upright wings and took only the duns that were canted to one side or the other with one wing up and the other down. So I fixed my fly so that it would float canted, and I was able to catch more of the fish.

This is the only time I have ever witnessed this super specific feeding behavior because the fish on the San Juan are not angler shy. You can really get close to them and they will continue to feed.

My theory is that these are super pressured fish, and when the hatches are dense, as with the BWO hatches on the San Juan, there are enough of these canted duns for the fish to feed just on these. I know that this type of super selective behavior exists, and it is not surprising to me that some fish will refuse a parachute and take a comparadun or vice versa.