Atlantic salmon

Atlantic salmon

The Atlantic salmon ( Salmo salar) belongs to the genus of the salmon and lives mostly in the Atlantic Ocean. However, in the late autumn the salmon move far up the rivers of Europe and North America to spawn in the headwaters. The fish can grow up to 1.5 meters long and need for spawning gravel reasons. At the end of " spawning migrations ", the females lay their eggs and the males fertilize them. Since the migration and Laichakt for the animals is very demanding and they also often take on the way no food, most of the salmon dies of exhaustion or by beneficiary diseases before reaching the open sea again.

The fry hatch, depending on water temperature after one to five months. At the age of about a year, they are strong enough to wander into the oceans. After a few years, they return to their birthplace to turn to spawn.

The situation in Germany

In Germany Salmo salar was to the 20th century home. He spawned in the tributaries of the Rhine, such as the victory. The Rhine was considered the most important and largest Salmon river in Europe. Even today, many place names, coat of arms or Guest to the former importance of the Rhine salmon.

By engaging the people in the ecosystem of the river the salmon population declined sharply. Reasons were overfishing or reorganization of the rivers. The impacts of industrial effluent deteriorated the living conditions for many species of fish. Thus disappeared until the mid-20th century, all the salmon from the Rhine and its tributaries. In 1950, then disappeared, the last salmon from the victory.

In 1987, of the International Commission for the Protection of the Rhine (ICPR ) decided the "Salmon 2000 Project", which should make the salmon in German rivers back home. It was successful. Today, the salmon is separated again in the Rhine and its tributaries, as well as found in the Elbe. But it will take decades until there is replicating itself salmon populations again. At the moment, hundreds of thousands of young salmon annually are exposed, of which only a fraction of returns.

In Baden-Württemberg rivers Kinzig, Murg Alb and was found again in 2011 spawning or live salmon or several spawning grounds.

For freshwater habitats him legal protection has been granted in accordance with the Habitats Directive.

Genetically modified salmon

The first genetically engineered animal intended for human consumption, a transgenic Atlantic salmon could be used. The GM salmon with the brand name AquAdvantage have a gene for a growth hormone from a different species of salmon americanus ( King Salmon ) and another gene from the adapted to cold ocean regions Zoarces species. Through these two genes, the GM salmon produce more growth hormones. Instead, after three years the battle maturity after 16 to 18 months is reached. The request was made in the USA in 1995, the FDA required safety tests were completed ( GM salmon are as safe as other salmon, according to FDA). Among other things, had to be ensured that the genetic modifications remain stable and have no adverse effects on animal health. All animals were also female and sterile and should be kept in closed tanks, so that an unwanted cross-pollination is not possible.

Name

In addition to the species names exist for the Atlantic salmon and colloquial names for the different age forms. As " Parr " refers to salmon that are older than two years and from the " smolts " by their " Parr - drawing " distinction ( dark vertical bars on the flanks ). In older records such juvenile salmon are also known as " smolt ". As a " smolt " refers to juvenile salmon (and sea trout ) on their first trip into the sea. At this stage the fish are usually silvery mainly. " Grilse " is the name of the salmon when they rise for the first time to spawn from the ocean back to the headwaters of the rivers. Usually the salmon has previously spent one and a half to two years in the sea. First, he comes as " Blank salmon " until it becomes colored salmon and the males eventually spawning the hook ( " hook salmon " ) form.