Coregonus lavaretus
The Whitefish
Finland's National Fish
The Whitefish (Coregonus lavaretus) is more than just a fish in Finland — it is a piece of national identity. In Finland it is called Siika (large form) or Muikku (small form) and is found in virtually every lake and along the entire Baltic coast.
The Muikku (Vendace, Coregonus albula) is Finland's commercially most important freshwater fish. Smoked or fried in butter, it is found at every Finnish summer market — and the annual Muikkukuningas (Vendace King competition) on Lake Puruvesi is an institution.
The large Whitefish (Siika) is a discerning sport fish in its own right. Its soft mouth and cautious bite make it a genuine challenge. In Finland, an entire angling tradition has developed around the Whitefish: mormyshka fishing through ice holes in winter and feather-light nymph fishing in summer.
Seasonal Data
The Whitefish is active year-round, with a feeding peak in late summer and early autumn — before spawning begins in October.
Diet Spectrum
The Whitefish is a filter feeder and bottom feeder. Zooplankton and chironomid larvae make up the bulk of its diet — which explains why mormyshkas are so effective.
Growth by Age
Growth varies greatly between forms. Large Whitefish (Siika) in nutrient-rich lakes can grow significantly faster than these average values.
| Age (Years) | Length | Weight | Relative Size |
|---|---|---|---|
| 1 | 10 cm | 10 g | 18% |
| 2 | 18 cm | 50 g | 33% |
| 3 | 25 cm | 140 g | 45% |
| 4 | 30 cm | 260 g | 55% |
| 5 | 35 cm | 420 g | 64% |
| 6 | 39 cm | 600 g | 71% |
| 8 | 45 cm | 950 g | 82% |
| 10+ | 55 cm | 1.8 kg | 100% |
Habitat Requirements
Water Temperature
Cold-water species that seeks cool deep layers in summer. Prefers the thermocline.
Oxygen
Sensitive to oxygen depletion. Winter die-offs possible under complete ice cover on shallow lakes.
Water Clarity
Filters plankton visually and with gill rakers. Needs good visibility for efficient foraging.
Lake Size
Prefers lakes with pronounced depth structure and thermal stratification. Also in Baltic coastal waters.
Substrate (Spawning)
Spawns in autumn on hard bottoms at 1 — 5 m depth. Eggs overwinter on the bottom until spring.
Food Supply
Growth correlates directly with plankton productivity. Mesotrophic lakes produce the best sizes.
Fishing Techniques for Whitefish
The Whitefish has a soft, small mouth and bites extremely cautiously. Fine tackle, thin leaders and tiny lures are essential. In Finland, two main methods have established themselves, both shaped by Finnish angling culture.
In winter, mormyshka fishing (Mormuska) is the ultimate discipline: a tiny, weighted artificial fly is moved up and down through an ice hole. Bite detection relies on an extremely sensitive nod-tip rod — every twitch of the nod could be a fish.
Mormyshka (Ice)
December — AprilTiny weighted nymph on a sensitive nod-tip rod. The quintessential Finnish method for Whitefish under ice.
Nymphs (Dropper Rig)
May — October2-3 small nymphs on droppers, under a float or indicator. Chironomid imitations in size 14 — 18.
Dry Fly
June — AugustWhen Whitefish are rising: CDC Midges and small Griffith's Gnats in size 18 — 22. Extremely fine tippet (0.08 mm).
Gillnet Fishing (Commercial)
Year-roundWith set nets and seine nets. The traditional method of commercial fishers — especially for Muikku.
Where to Catch Whitefish in Finland
Whitefish are found throughout Finland. These waters are known for particularly large specimens and excellent fishing opportunities.
Puruvesi (Saimaa)
61.7°N, 29.4°EFinland's clearest lake — Whitefish mecca
Crystal-clear water with visibility up to 10 m. This is where the legendary Muikkukuningas fishing competition is held every year. The Whitefish reach above-average sizes thanks to optimal food supply.
Inarijärvi
69.1°N, 27.6°EArctic Whitefish in Lapland
Finland's third-largest lake hosts several Whitefish ecotypes. The planktivorous form lives pelagically in open water, while the larger bottom-oriented form inhabits nearshore structures. Legendary for mormyshka fishing in early winter.
Bothnian Coast (Merenkurkku)
63.5°N, 21.5°EMigratory Whitefish of the Baltic
The anadromous migratory Whitefish of the Gulf of Bothnia reach the largest sizes of all Finnish forms. They enter coastal rivers in autumn and are caught there with nets and angling gear.
Päijänne
61.6°N, 25.5°EDeep-water Whitefish in central Finland
Finland's second-largest lake offers ideal conditions: deep, clear water with a pronounced thermocline. Whitefish hold at 8 — 15 m depth here in summer. Trolling with small crankbaits and mormyshka fishing in winter.
Finland's No. 1 Delicacy
Savustettu muikku — Hot-smoked small Whitefish on skewers. THE Finnish street food.
Paistettu muikku — Rye-breaded and fried Muikku with mashed potatoes.
Kalakukko — Traditional Karelian fish pie with Muikku in rye bread crust.
Loimulohi-style — Large Siika fillets roasted on birch board over open fire.
Whitefish roe (Mäti) is considered 'Finnish caviar' and is served pure on toast or blini with sour cream and red onion.
Mormyshka Tip for Beginners
Lure: 2 — 4 mm weighted nymph with red or orange spot. Often tipped with a single maggot or worm tip.
Technique: Move slowly up and down (2 — 3 cm strokes), with regular pauses. The bite shows as a minimal twitch of the nod — strike immediately, but gently!
Depth: Whitefish hold in winter just above the bottom (0.5 — 1 m above it). Search from bottom upward.
