Migratory Fishes


The Sea Trout very often is being regarded as the basic form of the trout of our homeland.

In German rivers the species “salmo trutta” appears in three different phenotypes.

As Brown Trout, being the typical and original trout of German streams and rivers.

As Lake Trout in big and cold lakes like the pre-alpine lakes in the South of Germany and as Sea Trout, spending its growth period in the estuaries and coastal waters of the North Sea and the Baltic.

The three phenotypes distinguish themselves by their migration behavior, which depends on the type of waters the trout lives in.

If migration distance to the sea is small, a big part of the Brown Trout will convert into Sea Trout, in the vicinity of a big lake, into Lake Trout. Nature takes care that the habitat will be used to the best advantage of the species. The migration to the sea is risky. The feeding resources yet gigantic in comparison to a small stream.

The habitat on the other hand shape the phenotype of the individual fish. In a small stream they stay smaller, mostly not longer than 60cm and brownish with red dots. In the pre-alpine lake and in the sea the grow to stately sized individuals of shiny silver. More than 20kg and over a meter long are possible.

“Salmo trutta” is a perfect example for the wonderful and miraculous world under water with its huge variety of lifeforms being well adapted to their habitats. The historic stocks of Brown Trout, Lake Trout and Sea Trout were close to being extinct.

Like with the Salmon, migratory fishes projects all over the country are struggling to rebuild the stocks. The Sea Trout is especially affected by obstacles blocking its migratory path like dams and hydropower stations.

The number of cormorants and other fish eating birds has increased dramatically over the last decades. In winter, when the great lakes are covered with ice, it happens regularly that great numbers of cormorants intrude into the spawning habitats of Trout in small rivers to satisfy their enormous nutritional needs.

These birds are threatening the genetic reserve of the eventually last remaining native Brown Trout, Lake Trout and Sea Trout.