Fly Fishing For Trout - Mending is as Important as Casting

The key to catching trout when fly fishing is getting a good drift. It really is one of the most important factors for achieving success particalarly with nymph and dry-fly fishing.

Why does the speed of drift matter? It is important to get the fly drifting at the same speed as the current for two reasons. Your flies will sink a lot faster which can be very important when trying to get the fly down to where the trout is especially in a short drift.

You don't have to use as much weight on your flies which makes casting a lot easier and more enjoyable. Trout can be very sensitive to an unnatural drift, they generally one take it if it's being pulled downstream too fast.

When I first started trout fishing at around the age of 12 I got good at casting quite quickly by practising on the lawn.  But it took me a long to start catching trout regularly because I wasn't paying much attention to the drift. I would fish in the Waitahanui river casting just as well as the people around me, but they would be catching heaps of trout while I was lucky to get one in a whole days fishing. The people who were doing well would even give me their flies to try.  The same casting, same flies, same leader length.  Nobody ever mentioned mending the line to avoid drag but I believe that was the missing link.  The trout hug the bottom in this river and I probably wasn't getting the flies down far enough.

What is drag?

The term drag refers to the line pulling on the fly causing it to drift faster or slower. Drag is caused when one section of the line is in water flowing at a different speed. For example if you have cast you fly across the main current into a slow section near the far bank the line in the stronger current will travel down stream faster this will pull on the rest of the line causing it to speed up as well. The worst situation for this is in the eye of a pool when the current swirls around and actually flows upstream in places.

How can a good drift be achieved?

The best way to avoid drag is by position yourself well.  This means putting your self in a place where after the cast the whole line will be travelling at the same speed or as close as is possible.  Sometimes it's not possible to do this, which is where mending comes into play.  Mending is simply repositioning the line to maintain a good drift.  For example if a section of fast current has started to form a downstream bow in the the line you have to flip that section back upstream to keep it drifting nicely.  The real trick is to do this without pulling on the fly too much.  This requires a lot of experimentation and practice.