Kosiojärvi

Character of the water

Kosiojärvi lies in the cold north — a northern nutrient-rich lowland lake. In summer a thermocline settles around 9 m and splits the lake into two worlds.

The surroundings

The lake lies half-remote, a fair way from the nearest road, tucked into woodland.

A small but surprisingly deep pocket (18 m) with steep drops straight down from shore — the bottom falls away fast.

Permits & rules

Fishing permit required — Kosiojärvi FVOF. Day permit ~140 kr · annual permit ~700 kr.

• Pike: keep at most one over 75 cm per day.
• Handheld tackle only. Respect the protected zones at the inlets and outlets.

Fishing Kosiojärvi

Kosiojärvi holds 4 species, with perch and pike at the top of the chain and roach and bream schooling beneath them. The depth gives the water two storeys — and the fish move between them with the season.

Whoever fishes Kosiojärvi regularly builds something of their own: a log of what took, where and when. That's how the water gives up its patterns — cast by cast, never all at once.

General rules of thumb for this kind of water

• Stratified, oxygen-poor lakes push the fish up above the thermocline in summer.
• Nutrient-rich lakes hold plenty of baitfish but often murky water.