Washington coho; especially Puget Sound coho, are indeed a tough nut to crack but to fair they are tough on all gear types. As has been touch on the major reason our coho are so tough if the high fishing pressure they have recieved which seems to have left us with mostly non-aggressive fish with the few aggressive fish quickly removed from the population by anglers very year.

Coho seem much easier in the salt again as mentioned enough are caught incidentially in our steelhead and other river fishing to indicate that they should be a possible fish to target in our rivers. Over the rivers I have caught lots of them while fishing for sea-runs cutthroat. When I began to target coho I used my cutthroat success as a foundation upon which to built a strategy to chase them.

That strategy includes smallish flies, strip retrieves, etc with constant changing of fly color and variation with the speed of the strip during retrieves. As with the cutthroat the coho seem to be easier on the fly in specific locations. I like slow froggy water, sloughs and side channels and as with the cutthroat having wood in the water seems to be an asset an in this case having rolling fish seems to be a good thing. If I were limited to one fly it would be a Knudson spider in a size #4. I would have a variety tied with different color bodies; including chartreuse, black, orange, yellow and pearl. I would also include in my fly box some flash flies, muddlers, and bait fish patterns. While most would be in that 1 inch length I would include some smaller and larger flies in the mix. Nearly all the flies I use are unweighted though if one wants to cover all situation the use of weighted "jig" type flies can be an asset.

For presentation I fish mostly sinking lines; including both sink tips and full sinking lines and once in a while I have success with dry lines and a fly fished just under the surface. If I had to limit myself to single line it would be full sinking line with a moderate sink rate. In almost all cases a stripped retrieve will outfish a swung fly though our coho can be pretty fussy about the retrieve rate and length of strip. Consistent success requires constant experimentation. One thing I have learned is that after one takes a fish or two out of a pod changing flies (at least color) and/or retrieve rate can add a fish or two to the day's catch.

As noted once the fish get close to spawning (getting colored) they tend to get much more aggressive and better biters. However those fish are generally not very good fighters and in my opinion not really worth targeting; they have more important things to do. Fresh run/bright fish be another matter. Traveling fish have typically been a tough nut for me to crack with my best success being with tide water fish. For those fish I like to target locations where those traveling fish are likely to pause. I have best luck on fish that have have stopped migrating and are schooled up though those fish that have been holding for any length of time are not as like to respond to the fly as the ones that have been there for a day or two.

A major factor in freshwater coho fishing for these non-aggressive fish is that they seem to lose interest in the fly before taking it. For that reason fishing in situations with reduced visibility can be the key. The most obvious example is our rivers after a significant rise while still fairly turbid - like that 12 to 18 inch visibility situation. Glacial water may be the best. When the river is clear I like fishing around snags. logs, and root wads where I can surprise the fish with the retrieved fly so that I get a reaction bite - in short try to present the fly so that fsih doesn't see the bug until it is within a foot or two of the fish. The idea is get the fish to take before losing interest.

Even with all the above the reality is the fly angler will have blank days but I have had enough multiple fish days (even some double digit ones) to make the coho game worthwhile.

BTW -
I too have caught coho well into the year include a number in March. Have taken fish as late as the last day of March in both the Snoqualmie and Skagit system. At one time Washington had coho with a wide variety of run timing. Some of that variety still exists - I have caught coho in our local rivers every month of the year except April and May.

Tight lines
Curt