Brown trout live in lakes all over the world. The change in water depth in lakes allows them to hide and be selective when they move through open water in search of food. As long as water temperatures average below 65 degrees, brown trout can likely survive in still water.
Brown trout are some of the hardiest of the trout species. They can withstand fluctuating conditions and come out the other side unscathed. They can live in places with cool water temperatures, consistent food sources, and enough cover and structure to hide.
Brown Trout in Lakes
I love fishing for brown trout in lakes. They present a different challenge than brown trout in rivers and streams. They keep their aggression but spend time in different areas and have different tendencies. Most lakes where you find brown trout are in places with higher elevations and consistently cool temperatures to keep the fish healthy.
Mountain lakes in the West, the cool waters of the Great Lakes, and spring-fed lakes on the East Coast hold brown trout populations.
Ideally, trout live in water that rarely gets above 65 degrees. Water temperatures below 65 degrees are highly oxygenated and comfortable for brown trout. For lakes to keep temperatures below 65 degrees, they need to be at elevation, spring-fed, or in areas with consistently cool temperatures.
If the water temperatures spend too much time over 65 degrees, trout can die. In the warmer months, you’ll find trout in the deepest sections of lakes, where the water is the coolest. In the colder months, brown trout roam all levels of the water column since the entire lake is likely below 65 degrees.
Water temperature is vital for trout survival, so if you’re fishing a lake with temperatures consistently over 65 degrees, it likely doesn’t hold a population of brown trout.
In warmer areas, game and fish departments may stock brown trout in the winter months. Anglers can target them in the winter, and the fish likely die in the summer. Growing up in Minnesota, we had many lakes stocked with brown trout in the fall so that we could fish with them all winter and spring.
Brown trout thrive in lakes with sand and rocky bottoms. The hard-bottom lakes make feeding and spawning easier. Plus, gravel-bottom lakes hold gravel-dwelling insects that they eat. Trout can also blend into gravel and sand more easily than vegetation.
Trout also want plenty of cover and structure in their lakes. While they cruise the open water during feeding times, they want to spend their days near structure and cover. They’re vulnerable to predators, so the more areas to hide, the better. Trout hide up shallow and deep depending on water temperatures and food locations.
Trout also like lakes with a stream or river flowing in or out of them. The moving water produces more oxygen and food. An attached stream or river allows the trout to swim into it during the spawn.
If the lake has suitable water temperatures and conditions, it likely has the necessary food sources. Trout love to feed on insects, crustaceans, and smaller fish. Water-dwelling insects make up the majority of a trout’s diet.
Insects will begin their lives at the bottom of the water column as eggs and nymphs. They’ll crawl around on the bottom as they grow. Trout love eating insects in the nymph stage. As the insects move closer to the adult stage, they’ll rise in the water column and sit on the surface while waiting for their wings to dry.
These events are called hatches. Hatches occur in the mornings and evenings, when brown trout feed most. You know a hatch is occurring when brown trout feed on the surface. This is one of my favorite times to fish for brown trout.
Crayfish and freshwater shrimp are the primary crustaceans brown trout like to eat. If a lake has a healthy population of either, brown trout thrive.
Finally, brown trout like to eat smaller fish. As a fly angler, if I find a brown trout population feeding on smaller fish, I know it’s time to throw my streamers. Brown trout that feast on smaller fish are aggressive and a blast to catch.
Brown Trout Spawn in Lakes
If brown trout exist in a lake with no river or stream attached, they will spawn in it. They search for a shallower section of water with a gravel bottom. Or, they’ll look for a shallower place against a rock wall to spawn.
Males dig the redds (holes in the gravel for eggs to sit), females lay the eggs, and males fertilize them. Then, they wait a few weeks for the eggs to hatch. As the eggs are growing, males and females protect them.
Ideally, brown trout have a stream or river to swim up to complete the spawn, but they can do it without one.
Brown trout that live in lakes have the potential to grow larger than those that live in rivers and streams. The friendlier conditions and accessible food allow them to feed more than in a river or stream. Plus, they can spawn and reproduce without the moving water, so brown trout populations can sustain themselves as long as the conditions align.