Salmo trutta lacustris
The Lake Trout
The Silver Huntress of the Deep
The Lake Trout (Salmo trutta lacustris) is the lacustrine form of the Brown Trout and inhabits Finland's large, deep lakes. In Finland it is called Järvitaimen and is one of the most coveted and simultaneously rarest freshwater fish in the country.
Unlike its stream-dwelling ancestor, the Lake Trout has adapted to life in open water. It lives pelagically, following schools of Whitefish and Smelt through the depths, and grows considerably larger than the Brown Trout — specimens over 5 kg are not uncommon, and in optimal waters over 10 kg are reached.
The Lake Trout is endangered in many Finnish waters. Obstruction of its spawning tributaries, overfishing and changes in lake ecology have severely reduced natural populations. Extensive stocking programmes maintain the populations in many lakes, but self-sustaining wild stocks have become rare.
Seasonal Data
The Lake Trout is most active in midsummer — when it follows Whitefish schools through open water and the trolling season reaches its peak.
Diet Spectrum
The Lake Trout is a specialized fish predator. Large specimens feed almost exclusively on Whitefish and Smelt — they follow baitfish schools pelagically through the open lake.
Growth by Age
The Lake Trout grows considerably faster in nutrient-rich great lakes with good Whitefish stocks than Brown Trout. Trophy specimens over 5 kg are certainly possible in Finland.
| Age (Years) | Length | Weight | Relative Size |
|---|---|---|---|
| 1 | 10 cm | 10 g | 13% |
| 2 | 20 cm | 80 g | 25% |
| 3 | 30 cm | 260 g | 38% |
| 4 | 40 cm | 650 g | 50% |
| 5 | 50 cm | 1.3 kg | 63% |
| 6 | 58 cm | 2.1 kg | 73% |
| 8 | 68 cm | 3.5 kg | 85% |
| 10+ | 80 cm | 6.0 kg | 100% |
Habitat Requirements
Water Temperature
Cold-water species that retreats to deeper, cooler layers in summer. Prefers the thermocline.
Lake Depth
Lives pelagically in Finland's great lakes. Needs deep, cold and oxygen-rich water bodies.
Prey Availability
Specialized on schooling fish like Whitefish and Smelt. Actively follows schools through the open lake.
Oxygen
Requires high oxygen levels even at depth. Summer stagnation can severely restrict habitat.
Thermocline
In summer, the Lake Trout hunts preferably along the thermocline where prey fish concentrate.
Spawning Habitat
Ascends gravelly tributaries to spawn. Connectivity of waterways is vital for the population.
Fishing Techniques for Lake Trout in Finland
The Lake Trout is a fish of the open water. Its pursuit requires different methods from Brown Trout fishing — here it's about covering vast areas, fishing deep water and locating roaming baitfish schools.
Trolling is by far the most successful method: lures or baitfish are towed at various depths behind the boat. Modern sonars help locate the thermocline and baitfish schools.
Trolling
May — SeptemberTHE method for Lake Trout. Lures or baitfish are trolled at 5-20 m depth behind the boat. Sonar and downrigger are key equipment.
Spin Fishing from Rapids
May — JuneDuring the spawning run, Lake Trout enter the tributaries. Large spinners and crankbaits at rapids and river mouths are highly effective.
Downrigger Trolling
June — AugustIn midsummer the fish are deep. Downriggers reach precisely the 10-25 m depth where Lake Trout hold along the thermocline.
Where to Catch Lake Trout in Finland
Lake Trout are found only in Finland's large, deep lakes. These waters offer the best chances for trophy specimens.
Inarijärvi
69.1°N, 27.6°EArctic great lake
Finland's third-largest lake in the heart of Lapland. Inari harbours one of the country's best Lake Trout populations, supported by regular stocking and strict regulation. The clear, cold water provides ideal conditions.
Päijänne
61.6°N, 25.5°EFinland's deepest lake
At over 95 m depth, Päijänne offers perfect conditions for Lake Trout. The rich Whitefish stocks ensure good growth. Trolling is the dominant method here, particularly in early and late summer.
Höytiäinen
62.7°N, 29.5°ERestored Lake Trout water
A prime example of successful reintroduction. Through targeted stocking and habitat restoration, Höytiäinen has been developed into one of eastern Finland's most productive Lake Trout waters.
Pielinen
63.2°N, 29.5°EEastern Finland's great trout lake
Finland's fifth-largest lake with its numerous islands and deep channels is a traditional Lake Trout water. The combination of large surface area and rich food supply enables impressive fish.
Adipose Fin — Wild or Stocked?
Tip: Check the adipose fin while the fish is still in the water, before landing it. When in doubt, always release and consult your guide.