Sea trout

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Salmo trutta morpha trutta
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Salmo trutta forma trutta
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Salmoniformes
Family: Salmonidae
Genus: Salmo
Species: S. trutta
morpha:S. t.  morpha trutta
Trionomial name
Salmo trutta morpha trutta
Jumping sea trout

Sea trout is the common name usually applied to anadromous (sea-run) forms of brown trout (Salmo trutta), and is often referred to as Salmo trutta morpha trutta. Other names for anadromous brown trout are bull trout, sewin (Wales), peel or peal (southwest England), mort (northwest England), finnock (Scotland), white trout (Ireland), Dollaghan (Northern Ireland) and salmon trout (culinary). [2]

Contents

The term "sea trout" is also used to describe other anadromous salmonids, such as coho salmon (Oncorhynchus kisutch), coastal cutthroat trout (Oncorhynchus clarkii clarkii), brook trout (Salvelinus fontinalis), Arctic char (Salvelinus alpinus alpinus) and Dolly Varden (Salvenlinus malma). [3] Even some non-salmonid fish species are also commonly known as sea trout, such as Northern pikeminnow (Ptychocheilus oregonensis) and members of the weakfish family (Cynoscion). [3]

Range

Anadromous brown trout are widely distributed in Europe along the Atlantic and Baltic coasts, the United Kingdom and the coasts of Iceland. They do not occur in the Mediterranean Sea but are found in the Black and Caspian Seas and as far north as the Barents and Kara Seas in the Arctic Ocean. [4] [5] Brown trout introduced into freshwater habitats in Tasmania, Victoria, New Zealand, Falkland Islands, Kerguelen Islands, Chile and Argentina have established anadromous populations when there was suitable access to saltwater. [4] [ failed verification ] Anadromous behavior has been reported in the Columbia River and its tributaries in the U.S. and in Canadian rivers on both the Pacific and Atlantic coasts. [6]

Taxonomy

As treated here, the anadromous sea trout Salmo trutta morpha trutta is not taxonomically distinct from the freshwater-resident forms of the brown trout, i.e., the lacustrine S. t. morpha lacustris and the riverine S. t. morpha fario, although previously they have been considered different subspecies or even species. They represent ecological forms with different migration behaviour. Originally, the name Salmo trutta was used to refer specifically to the anadromous or sea-run forms of brown trout. [7] Early angling literature often referred to sea trout as white trout or bull trout. [8]

Description

Anadromous brown trout are a silvery color with faint black spots. However, once they return to freshwater, they quickly take on the normal coloration of resident brown trout in preparation for spawning. Sea trout kelts (post spawn) return to their silvery stage as they migrate back to saltwater. [9] Adult brown trout are 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). Breeding males will develop a hook-like, upward-facing protrusion on the lower jaw called a kype. In freshwater the top of the trout is an olive color with brown and black spots, with the ventral side being tan to yellow. The sides have many orange and red spots ringed with a light blue. [10]

Life cycle

Their average length is 60 cm, but they can grow up to 130 cm in length and weigh up to 20 kg under favourable habitat conditions.

Their most striking feature is the long, elongated, torpedo-shaped body. They have silver grey sides and grey-green backs. The belly is white. Like all trout species the sea trout has an adipose fin.

Sea trout feed mainly on fish, small crabs, shrimps and prawns.

It is an anadromous, migratory fish, which closely resembles the Atlantic salmon in its form and lifestyle. In the sea, it makes long journeys and also swims upstream into small rivers in order to spawn. Spawning occurs in winter on gravelly river beds in the grayling zone to the barbel zone. Their eggs are laid in troughs or redds. The young fish remain in freshwater for one to five years and then make their way to the sea. The "inner clock" signals to the fish when they need to make their return journey to the sea. During this migration, they can cover up to 40 km per day.

Fish that are ready for spawning are usually lean and have to eat a lot of food in order to increase their energy levels as quickly as possible. After completion of the spawning process, the fish return to the sea. The mass mortality after spawning that is common in some species of salmon is not usual for brown trout. Once back in the sea, the fish regain their weight and lose their brown spawning colouring.

The surviving young of sea trout will generally migrate back to the sea, to feed in estuaries and coastal waters. However it is also known that the adult brown trout, which may have spent some years entirely in a river, can, for whatever reason, decide to migrate to sea, to return next year as a much larger (sea) trout, with silver colouration.

Threats

In many rivers of Central Europe, the sea trout have been extirpated because hydropower plants prevent spawning migration. In addition, many spawning grounds have disappeared due to the backflooding of rivers. In more recent times, sea trout have succeeded in re-establishing themselves in some lakes and rivers through the introduction of fish ladders and bypass channels around hydropower plants. In this way spawning migration has been enabled again, albeit in a limited way.

Angling

Sea trout are popular with anglers and as food. The close season lasts at least three months depending on river authority regulations. Like salmon, sea trout are protected by law in the Rhine river system and in most German rivers (except some northern German rivers) all year-round.

In the coastal waters of Schleswig-Holstein, sea trout is protected from 1 October to 31 December. This applies only for fish in spawning colour (brown), the silver coloured fish may continue to be caught. In most estuaries angling is completely prohibited in a protected area of 200 metres around the river mouth during this time.

In the coastal waters of Mecklenburg-Vorpommern, there is a general prohibition on fishing for sea trout from 15 September to 14 December. This applies both to fishermen and anglers.

In Germany, the term Absteiger is used by anglers to describe a sea trout after spawning. The removal of absteigers is a controversial topic among anglers. Most anglers refuse to take sea trout that have spawned because their meat is inferior and dry.

In North Wales the rivers Clwyd, Elwy and (to a lesser extent) Aled have runs of migratory trout, otherwise known as sea trout or, locally, sewin. Sewin generally refers to smaller sea trout up to around 30 – 40 cm in length. Fishing (angling) for sea trout is usually carried out at night using fly fishing techniques, but only when the rivers are running clear. Sea trout are very easily "spooked" by bankside disturbance and during daylight hours tend to be tucked up under the banks and submerged tree roots, and therefore very hard to catch. At night they feel more confident to come out into the main river flow and can often be seen "running" (migrating upstream) in the shallow runs during the months of May to November. When the rivers are flowing coloured in a spate following heavy rain, it is possible to catch sea trout during the day with artificial lures or spinners. The fishing season for sea trout in the Clwyd catchment is from March 20 to October 17 inclusive. Many fly fishermen would agree that night fishing for sea trout can be one of the most exciting forms of the sport as the fish can grow to more than 10 lbs (5 kg) in weight. The Rhyl and St Asaph Angling Association [11] controls 20 miles of river fishing on the rivers Clwyd, Elwy and Aled.

Related Research Articles

<span class="mw-page-title-main">Trout</span> Freshwater fish from subfamily Salmoninae

Trout is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera Oncorhynchus, Salmo and Salvelinus, all of which are members of the subfamily Salmoninae in the family Salmonidae. The word trout is also used for some similar-shaped but non-salmonid fish, such as the spotted seatrout/speckled trout.

<span class="mw-page-title-main">Fish migration</span> Movement of fishes from one part of a water body to another on a regular basis

Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear.

<span class="mw-page-title-main">River Clwyd</span> River in Wales

The River Clwyd is a river in Wales that rises in the Clocaenog Forest 5 mi (8 km) northwest of Corwen. Its total length is 35 mi (56 km).

<span class="mw-page-title-main">Brown trout</span> Species of fish

The brown trout is a species of salmonid ray-finned fish and the most widely distributed species of the genus Salmo, endemic to most of Europe, West Asia and parts of North Africa, and has been widely introduced globally as a game fish, even becoming one of the world's worst invasive species outside of its native range.

<span class="mw-page-title-main">Bull trout</span> Species of fish

The bull trout is a char of the family Salmonidae native to northwestern North America. Historically, S. confluentus has been known as the "Dolly Varden", but was reclassified as a separate species in 1980. Populations of bull trout in the lower 48 states are listed as threatened under the U.S. Endangered Species Act, and bull trout overall are listed as vulnerable to extinction on the IUCN Red List of Threatened Species. The Saskatchewan-Nelson Rivers population in Alberta, Canada is listed as threatened under the Species at Risk Act.

<span class="mw-page-title-main">Rainbow trout</span> Fresh-water species of fish

The rainbow trout is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead is an anadromous (sea-run) form of the coastal rainbow trout(O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.

Steelhead, or occasionally steelhead trout, is the anadromous form of the coastal rainbow trout (Oncorhynchus mykiss irideus) or Columbia River redband trout. Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and North America. Like other sea-run (anadromous) trout and salmon, steelhead spawn in freshwater, smolts migrate to the ocean to forage for several years and adults return to their natal streams to spawn. Steelhead are iteroparous, although survival is approximately 10–20%.

<i>Salmo</i> Genus of fishes

Salmo is a genus of ray-finned fish from the subfamily Salmoninae of family Salmonidae, and is part of the tribe Salmonini along with the sister genera Salvelinus and Salvethymus. Almost all Salmo species are native only in the Old World, the only exception being the Atlantic salmon, which is also naturally found across the North Atlantic in eastern North America.

<i>Arripis</i> Genus of fishes

Arripis is a genus of marine fishes from Australia and New Zealand, known as Australian salmon, kahawai and Australian herring. They are the only members of the family Arripidae. Despite the common name, Australian salmon are not related to the salmon family Salmonidae of the Northern Hemisphere, just as Australian herring are not related to herring of the Northern Hemisphere, but belong to the order Perciformes of perch-like fishes. Australian salmon were named so by early European settlers after their superficial resemblance to the salmoniform fishes.

<span class="mw-page-title-main">Atlantic salmon</span> Species of fish

The Atlantic salmon is a species of ray-finned fish in the family Salmonidae. It is the third largest of the Salmonidae, behind Siberian taimen and Pacific Chinook salmon, growing up to a meter in length. Atlantic salmon are found in the northern Atlantic Ocean and in rivers that flow into it. Most populations are anadromous, hatching in streams and rivers but moving out to sea as they grow where they mature, after which the adults seasonally move upstream again to spawn.

<span class="mw-page-title-main">Brook trout</span> Species of fish

The brook trout is a species of freshwater fish in the char genus Salvelinus of the salmon family Salmonidae native to Eastern North America in the United States and Canada. Two ecological forms of brook trout have been recognized by the US Forest Service. One ecological form is short-lived potamodromous populations in Lake Superior known as coaster trout or coasters. The second ecological form is the long-living predaceous anadromous populations which are found in northern lakes and coastal rivers from Long Island to Hudson Bay, which are referred to as salters. In parts of its range, it is also known as the eastern brook trout, speckled trout, brook charr, squaretail, brookie, or mud trout, among others. Adult coaster brook trout are capable of reaching sizes over 2 feet in length and weigh up to 6.8 kg, whereas adult salters average between 6 and 15 inches in length and weigh between 0.5 and 2.3 kg. The brook trout is characterized by its distinctive olive-green body with yellow and blue-rimmed red spots, white and black edged orange fins, and dorsal vermiculation. The diet of the brook trout is restrictive to the season and location of the fish, but will typically consist of terrestrial and aquatic insects, fry, crustaceans, zooplankton, and worms.

<span class="mw-page-title-main">Cutthroat trout</span> Species of fish

The cutthroat trout(Oncorhynchus clarkii) is a fish species of the family Salmonidae native to cold-water tributaries of the Pacific Ocean, Rocky Mountains, and Great Basin in North America. As a member of the genus Oncorhynchus, it is one of the Pacific trout, a group that includes the widely distributed rainbow trout. Cutthroat trout are popular gamefish, especially among anglers who enjoy fly fishing. The common name "cutthroat" refers to the distinctive red coloration on the underside of the lower jaw. The specific name clarkii was given to honor explorer William Clark, coleader of the Lewis and Clark Expedition.

<span class="mw-page-title-main">Arctic char</span> Species of fish

The Arctic char or Arctic charr is a cold-water fish in the family Salmonidae, native to alpine lakes, as well as Arctic and subarctic coastal waters in the Holarctic.

<i>Salmo trutta fario</i> Subspecies of Salmo trout

Salmo trutta fario, sometimes called the river trout, is a river-dwelling freshwater predatory fish from the genus Salmo of the family Salmonidae. It is one of the three main subspecies of the brown trout, besides sea trout and the lacustrine trout.

<span class="mw-page-title-main">River Elwy</span> River in Wales

The River Elwy is a river in Wales forming a tributary to the River Clwyd. Though the source of the river may be on the northern flank of Moel Seisiog, south-east of Llanrwst, the river only receives the name Elwy at the village of Llangernyw, where three rivers meet.

<span class="mw-page-title-main">Naugatuck River</span> River in Connecticut, United States

The Naugatuck River is a 40.2-mile-long (64.7 km) river in the U.S. state of Connecticut. Its waters carve out the Naugatuck River Valley in the western reaches of the state, flowing generally due south and eventually emptying into the Housatonic River at Derby, Connecticut and thence 11 miles (18 km) to Long Island Sound. The Plume and Atwood Dam in Thomaston, completed in 1960 following the Great Flood of 1955, creates a reservoir on the river and is the last barrier to salmon and trout migrating up from the sea.

<span class="mw-page-title-main">Westslope cutthroat trout</span> Subspecies of fish

The westslope cutthroat trout, also known as the black-spotted trout, common cutthroat trout and red-throated trout is a subspecies of the cutthroat trout and is a freshwater fish in the salmon family of order Salmoniformes. The cutthroat is the Montana state fish. This subspecies is a species of concern in its Montana and British Columbia ranges and is considered threatened in its native range in Alberta.

<span class="mw-page-title-main">Coastal cutthroat trout</span> Subspecies of fish

The coastal cutthroat trout, also known as the sea-run cutthroat trout, blue-back trout or harvest trout, is one of the several subspecies of cutthroat trout found in Western North America. The coastal cutthroat trout occurs in four distinct forms. A semi-anadromous or sea-run form is the most well known. Freshwater forms occur in both large and small rivers and streams and lake environments. The native range of the coastal cutthroat trout extends south from the southern coastline of the Kenai Peninsula in Alaska to the Eel River in Northern California. Coastal cutthroat trout are resident in tributary streams and rivers of the Pacific basin and are rarely found more than 100 miles (160 km) from the ocean.

<span class="mw-page-title-main">Kype</span>

A kype is a hook-like secondary sex characteristic which develops at the distal tip of the lower jaw in some male salmonids prior to the spawning season. The structure usually develops in the weeks prior to, and during, migration to the spawning grounds. In addition to the development of the kype, a large depression forms in the two halves of the premaxilla in the upper jaw, allowing the kype to fit into the premaxilla when the mouth is closed.

References

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  2. Everard, Mark. Britain's Freshwater Fishes. Princeton: PUP, 2013, p. 84.
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  4. 1 2 "Trout Facts-Sea trout". Wild Trout Trust. Retrieved October 3, 2016.
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  6. Bisson, Peter A. (1986). "Occurrence of anadromous brown trout in two lower Columbia River tributaries" (PDF). North American Journal of Fisheries Management. 6 (2): 290–292. doi:10.1577/1548-8659(1986)6<290:OOABTI>2.0.CO;2.
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  9. "Sea trout recognition" (PDF). Wild Trout Trust. Retrieved October 3, 2016.
  10. "Salmo trutta". Animal Diversity Web. Retrieved October 3, 2016.
  11. Rhyl and St Asaph Angling Association