Wednesday, June 18, 2008

Salmon Fishing Scotland The Atlantic Salmon.

Salmon Fishing Scotland The Atlantic Salmon.

The Atlantic salmon is a world traveller. It is an anadromous fish - one that spawns in fresh water but spends much of its life at sea.

External Features

* The Atlantic salmon has a scientific description going back to the 1700s, but even now, much remains unknown about its life history.

* The Atlantic salmon's historic range encompassed the North Atlantic Ocean and its freshwater tributaries from Ungava Bay to Lake Ontario and southward to Connecticut in North America, and from Russia's White Sea to Portugal on the European coast.

* Many of these runs are now reduced or extinct, especially in the southern portions of the species' range. However Atlantic salmon can still be found in the rivers of Ireland, the United Kingdom, Canada, Iceland Norway, Sweden, Finland, Russia, France, Spain, Canada and the United States. Click for map

* In some parts of Europe, small populations are returning to areas impacted by massive polution, including rivers in Germany (Rhine and Elbe), some rivers in Poland and even the Czech Republic, and rivers in the Baltic Republics of Lithuania, Latvia and Estonia.

Atlantic Salmon Life Cycle

* An Atlantic salmon undergoes many changes during its life. Pea-sized orange eggs are deposited in riverbeds in autumn. Early the following spring, thousands of tiny Atlantic salmon alevin emerge. These alevin are about two cm. long, and subsist off the attached yolk sac, hiding from predators in the gravel of the streambed. When the yolk sac is nearly gone the young fish wriggle up into the water, and are called fry until they are about five to eight cm. long.

* The Atlantic salmon later acquire vertical markings on their flank, identifying them as in the parr stage. Parr have dark backs, with 9 to 11 bars, called parr marks, along their sides - which act as camouflage. Parr remain in the river for two to 6 years, depending on temperatures and food supply.

* At a length of 12 to 24 cm., parr undergo a springtime transformation into smolt. Parr marks are replaced by a silvery coat for better camouflage at sea. Their internal systems adapt for saltwater life, and the fish leave their streams, travelling to ocean feeding grounds. Salmon from both sides of the Atlantic rendezvous in the waters off southwestern Greenland. Others travel to lesser-known oceanic or coastal feeding areas. They grow rapidly on a diet of small crustaceans and fish. They also must elude predators including larger fish and marine mammals.

* After one or more years at sea, following a hereditary route and timetable, Atlantic salmon return to their home rivers in an extraordinary journey that may span more than 4,000 km. of open ocean. If they return after one winter at sea, they are called grilse.

* Entering the river between April and November, they navigate upstream, leaping obstructions up to 3m. high to spawn in shallow tributaries in late fall.

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