Tuesday, April 22, 2014

Phototropism in action

An unusually late Easter break this year, coincided with a spell of gloriously sunny weather. Great for those participating in the annual Wacky Races caravan haul up the motorway, but for the flyfishers amongst us, somewhat less welcome you'll agree? Well yes and no.....for now is Grannom season in the north of England and a brief discussion on phototropism is merited.

Phototropism? Response to sunlight to you and me. And as the holidaying hoards displayed phototropic behaviour this weekend by driving to beauty spot lay-bys and then getting out the tartan blankets and deckchairs, so too did Brachycentrus subnubilis react in a positive way to the golden orb, by bursting out of the clear pools of the Cumbrian Eden in trout-exciting numbers.

Not that all invertebrates react to sunshine in such a significant way, in fact it's probably true to say that most positively shun brightness and come into their own from an angler's perspective when conditions are dull and cloudy. So far as I'm aware, we don't really understand why this does or doesn't happen, and precisely which orders/groups/species are sensitive. What we can say beyond reasonable doubt though, is that Grannom caddis pupae are very much phototropic - they are compelled to emerge in sometimes huge numbers when the sun shines.

Although I'd always had this vague sense that something along these lines was going on, it came into sharper focus for me about three years ago when I arrived at the river one late April morning to find an absolute blizzard of Grannom in the air as early as 9am. Closer inspection revealed that the hatch as such was all but over: I didn't see a single fly in the process of emerging, or on the water's surface, or being eaten by a fish. Sub surface tactics failed to interest a single fish, be it on nymphs or spiders or a combination of both. The only conclusion I could draw was that the adult flies I observed in such numbers, had popped out of the river at some point earlier on.The following day I was back - at dawn - in an attempt to preempt the little blighters. Unfortunately that particular enterprise proved a let-down and not a single Grannom was to be seen all morning. It was only later that I asked myself if the heavy mist I had arrived to, might have had some influence on the negative outcome. Nonetheless, the annual flight period was all but over by then and I ended up parking the theory; and to be honest, I didn't give it much of a thought for a good while afterwards.

Then last spring I had a conversation with Oliver Edwards which brought the whole phototropism thing right back into very sharp focus. Oliver and Stuart Crofts it turned out, are both convinced that something is happening with Grannom where sunlight is concerned. How many times Oliver asked, have you fished on a late April day of broken cloud, and found that the Grannom hatch in short pulses every time the sun peeps out for a few minutes? Good point says I, and heads off to the river to pay a bit closer attention to what I'm doing! Sure enough, once I started to open my bloody eyes a bit, it was glaringly obvious. A day on the Eamont proved particularly conclusive: a slow trickle of in evidence during the morning until a break in the clouds, and then BANG! Caddis explosion! A few minutes later when the sky darkened once more, there remained of course a blizzard of airborne adults......but a close look revealed that the actual emergence had ceased. Just like that. It was fascinating to see, and my thanks are due to Messrs Edwards and Crofts for the steer.......evidence once more that there is no such thing as being too observant; and the reason why such enterprising anglers remain at the cutting edge of our glorious sport.

Good conditions for a pulse of Grannom........

This weekend I was prepared. With the forecast set for wall-to-wall sunshine and the river low and clear, I dusted off my box of deerhair emergers (DHEs), and set forth with some hope of sport. What resulted wasn't exactly as I had envisaged, but who can complain when nudging a line forward into a gloriously warm and serene spring day?

Early exploration was made with a brace of nymphs on the French leader set up. I hoped that the shaggy brown hare's ear and cdc concoction on the dropper would attract interest, as it was placed to imitate any caddis pupae which might be making moves skyward. So when the first pool yielded two nice browns to that very fly, things were looking good. Sure enough, about 11:30am the first of the Grannom began to appear, popping out through the surface and bumbling away almost in one continuous motion......and as the hatch gathered momentum, I came upon my first properly rising trout of the new season; and it was a big 'un! On went the tapered leader and DHE and out went the cast. Up came the fish, and.........knocked it off! Bugger.
Luckily I found a couple more and successfully converted the resulting offers into fish landed. They were modest fish by Eden standards, the better of the two weighing a pound and three quarters (seen illuminated by spring sunshine at the top of the post); nevertheless, they were very welcome.

Unfortunately, that was it from a surface action point of view. An hour had passed and the air was filled with brown specks heading steadily off upstream.....but no more flies popped out of the water for the rest of the afternoon until I packed in at five o'clock, despite the sun continuing to blaze down unabated. Even Grannom need a siesta it would appear.

I can't complain though, because after returning to nymphs  - this time fished on a trio rig - I enjoyed intermittent sport through the rest of the session, with decent sized trout coming to either a jig back killer, or the 'white head melanist' PTN, regularly enough to keep me occupied. Trout are handsome creatures and I could never tire of catching them. I love the variation that they show, each one a distinct fingerprint, never to be repeated. The photos below are monochrome homages to such wild beauty. I dearly hope many more such encounters await me this season.


Andy said...

Interesting post Matt and as you say observation is the key..


Flyfisherman. Richard. said...

The photo's keep getting better Matt, well done stunning shots.