Sunday, September 01, 2013
Much ado about gnatting
I haven't been out much recently, but week before last I did make it onto the river with friend Mike Cooper. On that occasion a mass fall of black gnats brought quality fish up on several pools, and judging from the reports received from several fellow anglers, this carnival has continued up until now, much to the delight of local dry fly fishers.
What causes terrestrial insects to land on the water in such numbers is something I've yet to fathom. My limited understanding is that air temperature and and wind speed may both play a part. The latter is very evident when say hawthorn flies are out and about in spring - a calm day will see good numbers lazily grouped around the bushes from which they take their name.....but should the breeze kick up a notch and all of a sudden the awkward specimens are sent careering waterwards to become trout food in an instant.
The effect of air temperature can be seen in action in stillwater fishing when land bred insects blown over the water from the leeward bank inevitably end up on the surface. I assume this is due to the fact that water temperature over water is usually lower than over the adjacent land, and that when running into this cooler - and therefore denser - air, insects find it harder to remain airborne, for exactly the opposite reasons that paraglider pilot takes advantage of upwelling thermals on a mountainside. I also recall Stuart Crofts telling me once about how in early season, all manner of terrestrial insects - weevils, beetles and the like - can end up on the surface as they emerge from their winter hidey-holes in riverside trees; when the spring sun warms the bark sufficiently to tempt the critters into activity, they crawl around onto the shaded side of the trunk/branch and are promptly knocked for six by the sudden drop in temperature, falling groggily onto the water......a situation which can sometimes mask an assumed large dark olive hatch.
But I digress. What is certain is that the black gnats are falling and that is good news for those of us seeking some late season surface sport, after a few weeks where action was at a lull.
Faced with numerous rising fish, Mike and I found the going less straightforward than first expected. Once we realised what was going on (at first we had incorrectly assumed the fish were bulging at emergers of the few pale watery olives which were in evidence), we put up appropriate imitations and set to with gusto. But so swamped and at the current's mercy were these land bred Diptera that micro drag immediately showed itself to be a problem. Even on seemingly flat, even paced water, the fish were dismissive of any imitation which was not presented in exactly the correct foam lane - and so presenting the imitations from different angles was called for until the correct line was found.
Mike, despite being a relative newbie to river fishing, did extremely well to land a few fish and was desperately lucky not to snag a big 'un. He successfully negotiated the tricky bit, rising three fish in the 2lb plus category, but knocked each of them off on the strike. Hard lines mate, but the experience will stand you in good stead for next time around.
Meanwhile, I benefited from probably the easiest fish you could ever hope to catch. With a substantial trout rising behind an overhanging branch ahead - a fish I wanted Mike to have a clear shot at - I set about removing from the equation, a smaller specimen behind which I didn't want racing upstream and putting the prime target down. Whilst in position, I noticed a fish rise behind and slightly across from me, barely a rod length away. When it rose a second time, I flopped my imitation over my shoulder and let it track downstream, assuming I was about to hook a small fish at best. Well bugger me if a very nice fish of around 2lb didn't sidle up off the sandstone bed and eat the fly - in full view and touching distance of both me and Mike! It just goes to show how daft fish can become when totally preoccupied by an abundant food source. The photo below comes courtesy of Mike and his excellent waterproof camera - the easiest trout I've ever caught.
Unfortunately the clock was against us and we had to be away by 3pm. By this time the activity was slowing, but there were still fish to be had. It was however, great to see the residents active at the surface after a few weeks of doldrums.
Successful fly patterns on the day were the NDT (nondescript terrestrial), clipped Griffiths Gnat, and the blighter in the top photo which is a sort of bastard hybrid of the former two. It's proved to be quite handy with gnats so far this year. Dressing below:
Hook: Varivas 2200 #18
Thread: 14/0 black
Body: peacock herl on bed of HAN varnish
Wing: strands of Hends Spectra-flash #334
Post: single ply of TMC aero-dry wing
Hackle: grizzle cock, underside clipped flush
Finally, for those who haven't already visited, Mike Cooper is the author of the exceptionally entertaining Trout Vs Fly blog, which I have mentioned here before and is well worth a look. By his own admission, Mike is still a novice river angler; but from what I saw has a rewarding fishing life to look forward to, such is his enthusiasm, application and enquiring mind. I reckon his journey will be well worth following for those who appreciate a dose of good angling writing.