A Bit on Bugs

As described above, the Finnish water insect fauna is typically based on caddis (or sedge) flies. Almost all river and lake systems south of Lapland have caddisflies as their major large insect group. There are over 200 caddis species in Finland and only about 50 species of Mayflies and 30 something species of Stoneflies. Small and dark flat-winged flies and dragonflies together with damselflies can have considerable importance in lake fishing. Terrestrial insects, mainly ants, should not be forgotten. The following angler's names for the most important species are based on names used by John Goddard in his Waterside Guide.

Mayflies are important locally but adult duns and spinners are typically available only for short periods of time. Nymphs do represent better chances for consistent fishing. Those big Ephemera vulgata drakes emerging in June/July mainly in lake areas produce good fishing, but closely related E. danica is very rare. Olives, like medium to small (14-18 hook sizes) Baetis-species (most often B. rhodani, Large Dark Olive) and also the ubiquitous Ephemerella ignita (Blue Wing Olive) are common everywhere and important especially for grayling. Heptageniidae-species with their flat, crawling nymphs are quite common both in rivers and lakes, bright yellow H. sulphurea (Yellow May Dun, Yellow Hawk) is one of the easiest species to identify. In slow-moving rivers you can encounter some early Leptophlebia and Paraleptophlebia species (Sepia Dun, Turkey Brown). In northern Finland some large, dark Siphlonuridae-species (Large Summer Dun) can hatch in great numbers from early July on.

Of important stoneflies I already mentioned the early Taeniopteryx nebulosa or February Red, which can hatch heavily enough to interest even winter-stiff fish. Unfortunately the fickle weather of early spring often makes this otherwise fine hatch unfishable. Larger Diura- and related species (Medium Stonefly, Yellow Sally) come next in May and June and in Lapland dark Nemoura- and Leuctra-species (Needle Fly) abound late in the season. Stonefly-hatches, while rarely heavy, can usually be matched using appropriate, low-floating caddis patterns.

One of the main caddis species important to the fly angler is Rhyacophila nubila (closely related to the Sandfly, R. dorsalis), especially the larval and pupal stages. The green larvae (about size 10) are not cased and live in all fast-moving rivers. Also various Hydropsyche-species (Gray Flag, H. instabilis) are extremely common and their greyish-olive larvae make often up a major part of fish stomach samples. The importance of these two families is not easily overestimated and very few serious troutfishermen would dare to try their luck without several suitable imitations. Members of the big Limnephilidae-family (e.g. Cinnamon Sedge, L. lunatus) with their cased larvae can also be found in almost every watershed. Some of these species are big, robust insects and their erratic mating flight often triggers even the biggest trout to a splashy rise. Small Leptoceridae-species (Mystacides spp., e.g. Grouse-wing) abound around Midsummer, fish can be very selective when feeding on the surfacing pupae of these species. In many lakes the big Great Red Sedge (Phryganea grandis) is one of the most common insects.