Ecomare

Contrary to Pacific salmon, European salmon do not die directly after spawning, allowing them to make a second long voyage to their spawning grounds in the rivers.
Salmon and sea trout are difficult to distinguish from one another. According to the rule of thumb, a salmon can be picked up by its tail, whereas a sea trout cannot. The tail root of the sea trout is namely just as thick as the tip of the tail (and therefore slips easily out of your hand), while the tail root of the salmon forms a nice handhold because it is thinner.
Why they migrate so far away is largely unknown. Although there is a large supply of food near Greenland, the same holds true for areas in the North Sea. It has been suggested that the migration route is inherent and stems from the time when the North Sea was more land than sea (15,000-20,000 years ago). In those days, the mouths of the rivers ended in the Atlantic Ocean. Greenland was not that far from the river mouths and shortened the distance the salmon had to travel.

The salmon fisheries in the Dutch rivers reached a peak at the end of the 19th century. Since then, the catches have diminished and in the 1950s salmon was only sporadically caught in the Dutch rivers. Since 1957, salmon has completely disappeared in the Dutch fresh waters.
One attempted to maintain an artificial salmon population in the Rijn since 1985. First, 4000 1-year olds were released with the intention to repeat this every year up through 1990, resulting in 20,000 animals. Due to a poison disaster near Basal and fruitless attempts to retain the pollution, the project did not succeed. Salmon is categorized as an extinct animal species on the Dutch list of endangered freshwater fish species.

(Sport) fishing for salmon will soon be forbidden. The reason is to increase the number of sea trout in the rivers in Western Europe. Good news in this respect is that salmon eggs were found in 1997 along the gravelly banks of the Sieg, an unnavigatable German tributary of the Rijn and a long known spawning region of the anadromonous species. Anadromonous fish species live in seawater as adults and migrate to fresh water to spawn. Sea trout has been spawning longer in the Sieg.
Some biologists doubt whether the salmon will return; entrance to the rivers is closed by the Delta Works and the Afsluitdijk, to name a few, and there are too many flood-control dams and locks along the river to easily reach the spawning grounds. In addition, the temperature of the rivers such as the Rijn over the past century has risen by around 6 degrees Centigrade, whereby the water contains less oxygen which is necessary for burning off fat reserves.

Salmon farming has been taking place for at least fifteens years already, in countries such as Norway, Ireland, the Pharaoh Islands and Scotland. In 1998, there was more salmon farmed (900,000 tons) than caught in the wild (800,000). The demand for salmon has been increasing every year. Worldwide, 1.2 million tons of salmon were farmed in 2004 and more than twenty million kilograms in 2006 in the Netherlands.
There are a number of problems with farming salmon. The nurseries are a kind of bio-industry, whereby the salmon live very close together with all the dangers. Fish louse, a tick found on wild salmon, can easily spread and give the farmed salmon a diminished appetite and condition. The louse is combated with heavy toxic insecticides, which also kill plankton. The fish farmers also use a cocktail of anti-biotics, hormone disorderlies, organophosphates and anti-fouling to prevent diseases and algae growth. All of these materials produce an enormous waste which is dumped in sea and causes drastic changes in the marine flora and fauna. To make the fish heavier more quickly, artificial light is used at night in the winter in several fjords, to keep the fish eating.
In addition, the mixing of wild salmon with those that have escaped is a problem. In 2005, more than 300,000 salmon escaped in Norway after a severe storm damaged a nursery basin. Sabotage activities a year later also helped a record number of salmon to escape, around 800,000 specimen. Unidentified people cut cables many times, which bonded the nursery basins together. Farmed salmon can carry over diseases. There are also major consequences when salmon are genetically manipulated in order to grow more quickly and then mix with wild salmon, as happened in a nursery in Canada.

In 2003, the EC anounced a limit to the use of canthaxanthine, a coloring put into fish food to give salmon the pink color. Wild salmon get this color naturally from eating shrimp, but farmed salmon are not fed shrimp. Too much coloring causes crystals to grow on the retinas of the eyes. Farmers have decided to switch over to astaxantime, a slightly more expensive coloring for which there a no regulations as of yet.