Blog, news and reviews from Snowdonia Fly Fishing Guides
The hawthorn fly (Bibio marci), heather fly (Bibio pomonae) and black gnat (Bibio johannis) Hatches of these terrestrial flies are fairly common here, though short lived. The first to appear in the spring in the hawthorn, or St Mark's, fly. Some years the hatches can be spectacular but seem to have diminished over the last few years.
Next up is the heather fly that usually put in an appearance, but in smaller numbers, in the middle of summer. They are just as ungainly in flight as the hawthorn fly, but are usually a little smaller and have strikingly red thighs.
Black gnats can be seen in spring, summer and autumn sometimes in impressive numbers and locally I see the biggest hatches in late September and October.
They are all an important food source for trout and grayling as they are often blown onto the water, singly or sometimes in pairs, joined in mating.
The images below are of a male and female large Stonefly (Plecoptera microcephala). They are very easy to tell apart as the male has tiny wings, so small he is incapable of flight, where as the female has much longer wings and has to go in search of a mate. The nymphal stage is shown in a previous post.
Bugs are the pulse of this planet, without them we would all perish very quickly, they are cleaners, pollinators and a food source for other creatures.
As I've mentioned previously insects are under great threat and we should make greater efforts to protect them. On land it's evident that they are not as prolific as they once were, but underwater they are out of sight and largely out of mind. Our aquatic invertebrates are being decimated by pollution from agriculture, industry and sewage treatment plants with a chemical cocktail that not only kills them and their eggs but also destroys the habitat they depend upon.
This cute little critter is a heptageniidae (or flat bodied stone clinger) that will mature in to a beautiful up-winged fly (mayfly). It spends most of its life clinging to the underneath of a stone in the river and cannot survive if there is too much silt or algae on the gravels that form the riverbed. They were once common on a part of the river I often fish but over the last 5 or 6 years they have become much more scarce. At the same time a dairy farm expanded its operation and is spreading large amounts of slurry onto the fields bounding the river. The nutrients and chemicals from the slurry finds it's way into the water and creates algae on the once clean gravels and fine suspended sediments that drift in the river, all of which is detrimental to aquatic life.
This little bug was carefully returned to it's watery home and I hope it gets the chance to mature, breed and sustain the fragile population that's trying desperately to survive in a man-made hostile environment.
Just look at that face, cute or what? Bugs really are endearing little critters and this stonefly nymph proves the point.
Of great concern is that aquatic invertebrate numbers are collapsing at an alarming rate,
Riverfly insects have declined 59% since 1970, indicating poor water quality & an unstable food chain.** This is a growing problem not just in Britain but throughout Europe, Germany has recorded a decline of 75% in 27 years.
Not so long ago scraping squished bug gloop of the car windscreen was an essential task after a long drive, alas those days are gone. And this is worrying, not just because bugs are cute, but they are an essential part of the food chain for fish, birds and mammals.
**Source - Salmon & Trout Conservation
A well know fly fishing guide and instructor John can often be found fishing or guiding on the Welsh Dee or passing his knowledge to others at game fairs and country shows.
Guided fly fishing trips on rivers, streams and upland lakes in Snowdonia. and surrounding areas of North Wales.
Fishing for summer & winter grayling and wild brown trout.in the spectacular, tranquil countryside that is Snowdonia National Park.
Fly fishing and casting lessons for beginners. Casting fault analysis, single handed spey, slack line and presentation casting tuition for more experienced fly fishers.
Develop your watercraft skills on freestone rivers and upland lakes.