Sea trout

Sea trout is a common name used for a special kind of brown trout that lives both in the sea and in rivers. These fish are called anadromous, which means they spend part of their life in the ocean and return to freshwater rivers to spawn. They are found in many places and have several other names depending on the region, such as bull trout, sewin, peel, mort, finnock, white trout, or salmon trout.

The term "sea trout" is also used for other fish that share this sea-to-river lifestyle, including kinds of salmon and trout like coho salmon, coastal cutthroat trout, brook trout, Arctic char, and Dolly Varden. Some fish that are not even in the salmon family, like Northern pikeminnow and certain types of weakfish, are also sometimes called sea trout.

Range

Anadromous brown trout, often called sea trout, live along the Atlantic and Baltic coasts of Europe, the United Kingdom, and the coasts of Iceland. They are also found in the Black and Caspian Seas, and as far north as the Barents and Kara Seas in the Arctic Ocean. Though they do not live in the Mediterranean Sea, they have been introduced to freshwater areas in Tasmania, Victoria, New Zealand, Falkland Islands, Kerguelen Islands, Chile, and Argentina, where they have formed populations that can live in both freshwater and saltwater. This behavior has also been seen in the Columbia River and rivers along the Pacific and Atlantic coasts of Canada and the United States.

Taxonomy

Sea trout, known scientifically as Salmo trutta morpha trutta, are a type of brown trout that live in both sea and freshwater. They are not a different species from other brown trout, but they behave differently by migrating between the sea and rivers. In the past, they were sometimes called white trout or bull trout by people who loved fishing.

Description

Anadromous brown trout, often called sea trout, have a silvery color with faint black spots when they are in the ocean. When they return to freshwater to spawn, they change to the typical brown trout colors. After spawning, they go back to their silvery look as they head to the ocean again. These fish usually measure between 35 and 60 cm (14 and 24 in) long and can weigh from 0.5 to 2.4 kg (1.1 to 5.3 lb). During breeding, male trout grow a special hook-like shape on their lower jaw called a kype.

Sea trout can grow even larger, reaching up to 130 cm in length and weighing as much as 20 kg in the best habitats. They have a long, torpedo-shaped body with silver grey sides, grey-green backs, and a white belly. Like all trout, they have a special fin called an adipose fin.

Life cycle

The sea trout eats fish, small crabs, shrimps, and prawns. It is an anadromous, migratory fish that looks a lot like the Atlantic salmon. Sea trout travel far in the ocean and then swim upstream into small rivers to lay eggs. Spawning happens in winter on gravelly river beds in the grayling zone to the barbel zone. The eggs are laid in special nests called redds. The young fish stay in freshwater for one to five years before heading to the sea. These fish can travel up to 40 km each day during their journey.

When sea trout are ready to spawn, they eat a lot to build up energy. After spawning, they return to the sea. Unlike some salmon, most sea trout do not die after spawning. Once back in the sea, they regain their weight and their brown colour fades. Young sea trout usually go back to the sea to feed, but sometimes adult brown trout that have lived in rivers for years decide to migrate to the sea and return the next year as larger, silver-coloured trout.

Threats

In many rivers of Central Europe, sea trout have disappeared because big power plants stop them from moving to their spawning spots. Many places where they used to have babies are gone too. But recently, sea trout have started coming back in some lakes and rivers thanks to special paths called fish ladders and bypass channels built around the power plants. These help the fish move again, though not as much as before.

Angling

Germany

Sea trout are enjoyed by people who like to fish and cook them. There are times of the year when fishing for them is not allowed, called the close season, which lasts for at least three months. In many rivers in Germany, like the Rhine, sea trout are protected by law all year. In the coastal area of Schleswig-Holstein, fishing for sea trout is not allowed from October 1st to December 31st if the fish look brown because that means they are ready to have babies. But, if the fish are silver-coloured, people can still catch them. In most places near where rivers meet the sea, people cannot fish within 200 meters of the river mouth during this time. In another area called Mecklenburg-Vorpommern, no one can fish for sea trout from September 15th to December 14th, whether they are using boats or fishing rods.

Wales

In North Wales, rivers like Clwyd, Elwy, and Aled have sea trout, which people there call "sewin." These are smaller sea trout, usually up to about 30–40 cm long. People often fish for them at night using special fishing methods with flies, but only when the river water is clear. During the day, sea trout hide under banks and tree roots, making them hard to catch. At night, they feel safer and come out more, especially from May to November when they are moving upstream. If the river water is muddy after heavy rain, people can sometimes catch sea trout during the day using lures or spinners. The fishing season for sea trout in these rivers runs from March 20 to October 17. Many fishing fans think night fishing for sea trout is very exciting because these fish can grow really big, sometimes more than 10 lbs (5 kg). A fishing group called the Rhyl and St Asaph Angling Association manages fishing along 20 miles of these rivers.