A splake is a hybrid fish created by crossing brook trout with lake trout. The name itself is a mashup of “speckled trout” (a common name for brook trout) and “lake trout.” Hatcheries have been producing splake since the 1870s, making it one of the oldest deliberately created fish hybrids in North America. Wildlife agencies stock them in cold, deep lakes across the northern United States and Canada because they grow faster than either parent species and create fishing opportunities that neither parent could provide on its own.
Parent Species and How Splake Are Made
Splake result from fertilizing brook trout eggs with lake trout milt (or occasionally the reverse). Both parents belong to the char genus, Salvelinus. Brook trout are technically Salvelinus fontinalis, and lake trout are Salvelinus namaycush. Because the two species are closely related, the cross produces viable offspring reliably in hatchery settings.
Virtually all splake swimming in lakes today were raised in a hatchery and stocked. Natural reproduction between brook trout and lake trout is extremely rare in the wild, so you won’t find self-sustaining splake populations. Some fisheries programs also produce backcross splake by crossing a male splake with a female lake trout, resulting in fish that are 75% lake trout and 25% brook trout. These backcrosses behave more like lake trout and can thrive in deeper, colder water.
How to Tell a Splake Apart
Splake look like a blend of both parents, which makes identification tricky. The most reliable approach is to check several features at once rather than relying on any single trait.
- Tail fork: Lake trout have a deeply forked tail. Brook trout have a nearly square tail. Splake fall in between with a moderately forked tail. The depth of the fork varies from fish to fish, so this alone isn’t definitive.
- Spots and halos: Most anglers assume that blue halos around reddish spots mean brook trout, not splake. That’s not always true. Splake can have faint blue halos, though they tend to be lighter and less consistent than on a brook trout. The overall spotting pattern on a splake is a jumble of both parents’ markings.
- Vermiculations: These are the wavy, worm-like lines on the back near the dorsal fin. Brook trout display bold, clearly defined vermiculations. Splake often have some of this patterning, but it’s typically faded, broken up, or looks more like scattered spots than continuous lines.
In practice, splake get misidentified as brook trout far more often than as lake trout. If you’re fishing a lake where both species are stocked, look at the tail first, then examine the back for those worm-like markings. A fish with a slightly forked tail and washed-out vermiculations is likely a splake.
Faster Growth Than Either Parent
Splake exhibit what biologists call hybrid vigor. In controlled feeding trials, splake outgrew both parent species from the earliest life stages. By 16 weeks after first feeding, splake averaged 4.1 grams compared to 3.3 grams for brook trout and 2.5 grams for lake trout. That growth advantage continues into adulthood. In Maine waters where splake and brook trout were stocked side by side, splake consistently reached greater lengths at every age and survived to older ages, creating a higher-quality fishery.
This rapid growth is one of the main reasons wildlife agencies stock them. Brook trout in many lakes grow slowly and rarely reach impressive sizes. Lake trout grow large but take years to reach maturity. Splake split the difference: they put on weight quickly and, like their lake trout parent, can adapt to deeper water using their swim bladder. This lets them exploit habitat that brook trout typically can’t use.
Splake Can Reproduce, and That’s a Concern
For decades, fisheries managers assumed splake were effectively sterile or that natural barriers would prevent them from breeding with wild trout. That assumption turned out to be wrong. Research in the Great Lakes found that roughly 56% of captured splake were sexually mature. Splake have been documented appearing on both brook trout spawning streams and lake trout spawning reefs in reproductive condition.
Studies dating back to the 1950s showed that male splake crossed with female brook trout can produce viable offspring. More recent genetic work has confirmed that interbreeding between splake and both parent species is possible in the wild. This raises conservation concerns, particularly in waters that support native brook trout or lake trout populations. Some agencies now think carefully about where they stock splake to avoid genetic contamination of wild trout.
Why Agencies Stock Splake
Splake fill a specific niche in fisheries management. Many cold-water lakes can’t support warm-water species like bass, and stocking rainbow trout or brown trout isn’t always an option because those species could threaten native Atlantic salmon populations in connected waterways. Splake solve that problem. They provide a cold-water sport fish for lakes where the alternatives are limited.
Ice fishing is a major part of the equation. Many wild brook trout ponds are closed to fishing in winter to protect native populations. Stocking splake in suitable lakes gives ice anglers access to quality cold-water fishing without putting pressure on wild brook trout. Maine’s management plan specifically highlights this as one of splake’s most valuable traits.
To keep the fishery healthy, managers set harvest limits. Maine, for example, caps winter harvest at no more than 0.40 splake per acre to ensure enough fish survive to reach older, larger size classes.
Habitat Preferences
Splake inherit cold-water needs from both parents. Like lake trout, they require well-oxygenated water and prefer temperatures below about 15°C (59°F). During summer, they move to deeper, cooler layers of the lake, similar to lake trout, though they don’t typically go as deep. Their ability to regulate their swim bladder for deeper water gives them an advantage over brook trout, which tend to stay in shallower areas or streams.
In spring and fall, when surface temperatures drop, splake move into shallower water and become more accessible to shore anglers. This seasonal pattern is important for anyone planning a fishing trip.
How to Catch Splake
The best splake fishing happens in late fall and through the ice in winter, when the fish are active in shallower water and feeding aggressively. Live minnows are one of the most effective baits. Small spoons that mimic baitfish also work well, especially tipped with a piece of bait for added scent.
During open-water season, trolling with small spoons or stick baits near drop-offs and rocky structure produces fish, particularly in spring before the lake stratifies. Fly fishing can be productive in the same early-season window when splake cruise near the surface. Once summer pushes them deep, targeting splake requires downriggers or lead-core line to reach the thermocline where temperatures suit them.
Splake fight with more energy than lake trout of the same size, thanks to their brook trout genetics. They tend to make shorter, more aggressive runs rather than the slow, heavy pulls typical of lakers. Most splake caught by anglers weigh between 1 and 4 pounds, though fish over 10 pounds are taken regularly in well-managed lakes.