Trout

Trout are a group of fish that live in freshwater, such as lakes, rivers, and wetlands. They belong to several genera including Oncorhynchus, Salmo, and Salvelinus, and are part of the salmon family. Though they look similar to salmon, most trout spend their whole lives in freshwater, moving between smaller creeks and larger water bodies at different stages of their lives.

Some trout species, like the steelhead and sea trout, do travel to the ocean for part of their lives before returning to freshwater to spawn, much like salmon. Trout are important both as food for people and as a key part of the food chain in aquatic environments. They eat smaller creatures such as insects, crustaceans, and small fish, while also serving as prey for animals like brown bears, otters, and various birds.

Because trout play a vital role in their ecosystems, they help keep the balance of nature in both water and on land. Their remains provide nutrients for plants and other animals living near water. Trout are admired for their beauty and are popular among people who enjoy fishing, making them both ecologically and culturally important.

Species

The name "trout" refers to many species within three genera in the subfamily Salmoninae: Salmo, Oncorhynchus, and Salvelinus. Some well-known trout species include the Brown trout, Rainbow trout, and Brook trout. These fish are popular among anglers and are found in many freshwater habitats.

Other fish sometimes called trout, like the Spotted sea-trout, belong to different families but share a similar appearance.

Anatomy

Trout living in different places can have very different colors and patterns, which help them blend into their surroundings. When they are ready to mate, their colors become especially bright. Trout have soft fins without sharp spines and a small fatty fin near their tail. They also have a special air-filled organ called a swim bladder connected to their throat, which helps them stay balanced in the water.

There are many kinds of trout, and some look quite different from each other even though they are closely related. For example, in the eastern United States, the brook trout, aurora trout, and the silver trout look different but are actually the same species. Lake trout, found in big lakes in North America, can live for many decades and grow very large, much bigger than rainbow trout, which usually live about seven years.

Habitat

Trout are coldwater fish that live in cool, clear streams, wetlands, and lakes. They are found naturally in North America, northern Asia, and Europe. In the 19th century, people introduced some trout species to Australia and New Zealand, where they became popular among fishers but also affected some native fish.

Rainbow trout were brought to Australia in 1894 from New Zealand and are now widely enjoyed by recreational anglers. These introduced trout have had a significant impact on the distribution and abundance of native Australian fish, such as the climbing galaxias, despite millions being released annually from hatcheries. Some similar trout can be found in the Himalayan Region and the Tian Shan mountains.

Diet

Trout mainly eat other fish and small water animals such as flies, mayflies, caddisflies, stoneflies, mollusks, dragonflies, and zooplankton. When they grow larger, they mostly hunt other fish, sometimes eating fish up to one-third their own length.

Trout also enjoy eating land animals like insects and small animals that fall into the water, such as mice. They have a varied diet, which includes aquatic life like minnows and crawfish, making their eating habits quite flexible.

Trout as food

Trout is a popular food fish, often enjoyed for its tasty and tender flesh, similar to salmon. Its flavor can vary depending on what the trout eats, with those eating small creatures like crustaceans often tasting better than those that eat mainly insects. Because trout is so popular, many are raised on fish farms and then released into rivers and lakes where fishing is common, helping to replace fish that have been caught too often.

Trout meat is cooked in many ways, just like salmon, including smoking. In some places, such as China, farm-raised rainbow trout has sometimes been sold as salmon, which has caused concerns about honesty in food labeling.

Nutritional value

A typical serving of trout, about 79 grams or 2.8 ounces, provides good protein and relatively low fat, along with other nutrients. Here’s what you’ll generally find in one fillet:

• Energy: 490 kJ (117 kcal)
• Fat (g): 5.22
• Carbohydrates (g): 0
• Fibers (g): 0
• Protein (g): 16.41
• Cholesterol (mg): 46

Trout fishing

Trout are popular fish for people to catch because they put up a good fight. Fishers often use special baits and lures that look like the small animals trout eat, such as insects and small fish. There are different ways to fish for trout, like using a normal fishing rod or trying fly fishing, where special lightweight lures are used.

Trout can be found in rivers, lakes, and even under ice in winter. Some of the biggest trout ever caught include a lake trout from Great Bear Lake in Canada and a rainbow trout from Lake Diefenbaker in Canada. Fishers use many kinds of bait, such as waxworms, corn worms, and small flies, to attract trout.

Declines in native trout populations

Many native trout populations are facing challenges due to several factors, including invasive species, wildfires, and climate change. Non-native fish were introduced to improve fishing opportunities, but they often outcompete and displace native trout. These invasive species can also mix with native trout, creating hybrids that change the genetic makeup of the original populations.

Climate change is another big problem for trout. As temperatures rise, especially in inland waters, it becomes harder for trout to survive. They need cooler water to thrive, and warmer conditions can harm their populations. Efforts are being made to protect native trout, such as using sterile fish in hatcheries to prevent unwanted mixing of genes.