Its been a fairly good year on the Northfork with fish being a little bigger and more plentiful than the past three. The Mrs. and myself have had a few very good days but as usual fishing in the canyon always proves to be tricky at best. Typically, I fish a 0.5 mile section and then after I throw on the snorkeling mask to see what I haven't been catching. Its always a surprise to some heavy fish sitting in small holding pools. I have seem some very large fish but I have never managed to temp any of them.

In the last month the flows have dropped dramatically and are now sitting at below 50 CFS and the water temperatures have rapidly increased. The amount of algae and weed has also spread rapidly. Last weekend I didn't bring any fishing kit but I brought the mask and I found a number of the larger (12-16 inch) trout dead on the bottom of the deeper pools and I didn't see any other fish above eight to ten inch mark. The number of fish under the eight to ten inches was typical and they didn't looked stressed or sluggish.

Is something usual going on? There are a number of thing that I'm ruling out.

I don't believe that it is a lack of dissolved oxygen (DO) as the water is continually being agitated by riffles and plunge pools. Even in still water trout can handle fairly high temperature and low DO.

I don't believe that the fish were poisoned as all of the smaller fish, fry and the handful of small mount bass seem to be doing ok and there is nothing above this area apart from some gold panning.

Could it be stress related mortality? There are two families of mergansers in the area each with about 6-8 chicks, as the water level drops the refuge area for the large fish shrinks. Could it be the constant fishing pressure of these birds that is causing the large fish to die. I picked up a number of the dead fish and none of them showed signs of bill/beak marks, so if not physically harmed is it just a matter of stress that is killing the larger fish? 

Regards,

Denis

Some pics from this year