Trout

Quick Take

• There's an ancient, hands-only technique for catching trout, one that is actually illegal in several countries. Discover trout tickling →
• Steelhead and rainbow trout look like two different fish, though the truth about what separates them is more complicated than anglers admit. See the steelhead distinction →
• Introducing trout to a new continent seemed harmless at first. Then it wasn't. Explore their spread abroad →
• Male trout have an unexpected biological trick for winning over females that has nothing to do with size or strength. Explore trout spawning behavior →

The name trout refers to a type of freshwater fish that lives in cold rivers and lakes all over the world. Trout are native to North America, Europe, and other parts of the world. Most trout species fall into one of three categories: freshwater, saltwater, and anadromous. Anadromous trout spend time in salt water, but they return to freshwater streams to spawn.

5 Intriguing Facts About Trout

• Trout is one of the most popular game fish in the world.
• This fish thrives in cold, clean water.
• Trout don’t have scales in their first month of life.
• Trout that live in different places have different color patterns.
• Cooked trout is a delicious, nutrient-rich dish.

Evolution and Origins

Rainbow trout are naturally found in the North Pacific Ocean and connected river systems, ranging from the Amur River in eastern Asia northward along the Pacific coast — including the Kamchatka Peninsula and northeastern Russia — as well as along the Pacific coast of North America from Alaska to northern Mexico.

Trout were introduced to Australia and New Zealand by recreational anglers during the 19th century. This introduction had the unintended consequence of displacing and threatening various native fish species in upland areas.

Classification and Scientific Name

The name “trout” is commonly used for some species in three of the seven genera in the subfamily Salmonidae: Salmo, Oncorhynchus, or Salvelinus. The Salvelinus genus also includes fish referred to as char or salmon.

Species

The exact number of trout species varies depending on classification, but there are several recognized species in the genera Salmo, Oncorhynchus, and Salvelinus. Some sources mention up to 14 types if subspecies and hybrids are included, but hybrids are not considered true species.

The 9 species native to North America are:

• Brook trout (Salvelinus fontinalis)
• Bull trout (Salvelinus confluentus)
• Dolly Varden trout (Salvelinus malma)
• Cutthroat trout (Oncorhynchus clarki)
• Gila trout (Oncorhynchus gilae)
• Lake trout (Salvelinus namaycush)
• Apache trout (Oncorhynchus apache)
• Golden trout (Oncorhynchus aguabonita)
• Rainbow trout (Oncorhynchus mykiss)

The 3 hybrid trout species are:

• Palomino trout (also known as the golden rainbow) (Oncorhynchus mykiss)
• Tiger trout (Salmo trutta X Salvelinus fontinalis)
• Splake trout (Salvelinus namaycush X Salvelinus fontinalis)

Are you wondering about the brown trout? It is not native to North America. It is native to Asia and Europe, and it was introduced to North America in the 1800s.

Knowing which fish you’re referring to can be a little confusing when discussing a species this widespread and popular. For instance, brook trout (Salvelinus fontinalis) is a recognized species in the U.S. and is native to eastern North America. In the UK, the native trout is the brown trout (Salmo trutta), which is sometimes called ‘trout’ or ‘brown trout,’ but not ‘brook trout’.

The steelhead trout (Oncorhynchus mykiss) is sometimes confused with the rainbow trout. They are not the same fish, but a steelhead is an anadromous form of the coastal rainbow trout (O.m. irideus) or the Columbia River red band trout (O. m. gairdneri). Steelhead trout usually have thinner bodies and more silver coloring than freshwater rainbow trout.

Appearance

A trout is a large fish whose colors can vary depending on where it lives and what type of trout it is. It has a long, oval body, a small head, small eyes, and a wide mouth. Its most distinctive feature is iridescent spotting in various colors along its body. It is usually dark with silvery-gray scales on its sides.

On average, trout can reach 2 feet in length, but their size varies by species. Anadromous species are usually larger than freshwater species.

Their colors also vary according to species and location. Freshwater rainbow trout, for instance, are known for their bright pink and purple coloring, while steelhead trout are almost solid silver. Brown trout get their name from their brownish, spotted sides, and tiger trout have dark, distinctive stripes.

Distribution, Population, and Habitat

Trout prefer cold lakes, rivers, and streams. Their ideal temperature is 50 to 60 degrees Fahrenheit. They are among the most common fish in northern wilderness areas. Freshwater species may spend their entire lives in the streams or rivers where they were born. Others are migratory. They travel to the ocean, spend time there, and then return to the place of their birth to reproduce. The exact population number is unknown, and many native trout populations are declining or under threat due to habitat loss, climate change, and other environmental stressors.

Predators and Prey

Trout are an important food source for humans and animals. Some carnivores that eat trout include bears, eagles, otters, sawbill ducks, and larger fish like pike.

Trout are carnivores that feed on a wide variety of fish and aquatic animals. They will even eat mice and voles that fall into the water. Their diet includes:

• Crayfish
• Minnows
• Flies
• Mollusks
• Smaller fish
• Shrimp
• Dragonflies
• Worms
• Snails
• Grasshoppers

Reproduction and Lifespan

Male trout reach sexual maturity at two years old, and females reach it at three years old. Males attract females by changing their scale colors to bright pink or red.

Nest or Redd

They reproduce by spawning. The female first builds a nest by scooping out dirt and sediment to create a nesting area called a redd. Normally, she chooses a river bottom that has some gravel and sand. She deposits her eggs in the nest, and the male releases his sperm on top of the eggs. A trout can lay 200 to 8,000 eggs in a single spawning.

After 4 to 10 weeks, the eggs hatch. Many baby trout won’t survive. Most trout in the wild die before their first birthday.

Male trout can become aggressive when fighting over females and when defending their redds.

Fishing and Cooking

Cooked trout is a favorite among people who like seafood. Although trout tends to be bony, most people find it delicious. The flesh changes from pink to white once cooked. It is extremely tender with a delicate flavor. It is easy to cut and fillet.

There are endless ways to cook trout, including grilling, smoking, baking, and pan-frying. Most culinary experts say a simple recipe makes the best cooked trout. This allows the trout’s natural flavor to shine. Simple seasoning and grilling are all you need to make a spectacular trout fillet. Any recipe that calls for salmon will work with trout.

Trout is classified as an “oily” fish, meaning it is high in omega-3 fatty acids and low in calories and fat. The American Heart Association and other nutrition experts recommend eating oily fish for these nutritional benefits.

Trout are also popular as game fish, with trout fishing second only to bass fishing in popularity. The technique of fly fishing was developed specifically to catch trout in rivers. People who like ice fishing frequently hope to catch trout. In winter, trout stay close to the water’s surface looking for food, making them easier to catch. Rainbow and brown trout are the most common targets of ice fishing.

Trout tickling is an ancient way of catching these fish that doesn’t involve a rod, reel, or net. It involves stroking the trout until it falls into a trance. In Scotland, it’s called guddling. Trout tickling is illegal in some countries, such as the UK and Australia, where it is often associated with poaching.

Population

Brown trout is listed as Least concern by the IUCN Red List and the International Union for the Conservation of Nature. As a popular game fish, trout populations are regularly restocked by fishery departments in countries all over the world. In recent years, however, conservationists have expressed concern about the fate of trout and other fish.

Climate change has a direct impact on the cold temperatures these fish need to thrive. Wildlife biologists in some areas are concerned about the population losses of trout native to those regions. Habitat loss, water pollution, and rising temperatures have affected trout populations.

Wild and Cold

Trout are among the most sought-after and beloved fish for anglers who enjoy the challenge of catching them. Immortalized in books and movies about fishing, they are symbols of the wild, cold wilderness.