I remember once peering into a deep pool on a river somewhere, and not being able to see much, because of a layer of “scum” for want of a better word, and PD turning to me and saying (with the most subtle tones of disdain), “you like that stuff don’t you!”.
Yes I do.
The truth be told, such scum is often an accumulation of wattle pollen or flowers, and pollutants of unknown origin, and is blown into a pool by an awful berg wind, all of which I dislike with a passion. I have previously written of my inconsistent prejudices, well this must be another one then.
But think about it: who wouldn’t get a tingle of anticipation when rounding a bend in the river to find a pool with a deep shaded spot, covered by a rock overhang, or tree.
And is not a layer of something floating on the surface all the more special. It creates complete cover from above, often over open deep water that was lacking any cover before, and establishes a temporary prime lie. One that builds up over a few hours or days, and gets discovered by an opportunistic Trout. A Trout that ventures out, and takes up a rent-free space, where he may find a current delivering gourmet food, beneath the table cloth, so to speak.
You invariably won’t be able to see that fish, although I have once or twice encountered a fish that really pigged out and rose to take morsels trapped in the scum layer too, giving away his position. But in the ordinary course, it will just be a deep dark place that screams “Trout”. It presents a blind, that obscures your approach, and allows you to get really close to the unsuspecting fish that lies beneath.
I prefer not to drop the fly through the scum, because I don’t want that stuff adhering to the fly, but also because that is not likely how the natural food will enter the lie. Instead the insects will be deep in the flow that enters the lie under the scum. So I will cast well above, and then allow the fly to slide silently, naturally and enticingly in under the curtain of muck.
And once the fly is in there I tense up with anticipation.
PD shakes his head and walks on by.
I promise, sometimes it does yield a fish!
No, I don’t have a picture: It’s not pretty.