Never heard of the term...Seeforellen, but given the opportunity, ANY trout you refer to as Domestic, will eventually migrate to see, or big water, and become anadromous. And the big seatrout brown?...same as an Atlantic Salmon. I have contested this with the best of them, and have got admissions. They are virtually the same fish. The silver river brown that enters the river will turn dark, and look exactly the same as a brown when he has been in the river for very long. It becomes a flyfishing, marketing approach..."come fish our river for Atlantic salmon" for those that have caught the more common brown trout.

I actually live near streams that connect with saltwater here on the east coast. Here I have seen true searun brook trout (now keep in mind that they are close to non-existent now-a-days but a few still do exist). The state also stocks browns and rainbows and I have also seen those fish take to the saltwater as well. The difference is hard to tell because fresh fish coming from the salt have no color whether it be a brookie, brown, or bow. They all seem to have a nice silver sheen to them and they look entirely different from an ordinary stream trout. I have however noticed that once these fish migrate up into freshwater for a day or two they immediately regain their natural stream colors. This alone makes guessing the strain of trout a little difficult to tell in some areas like where I am from. I have done some side work at a hatchery near my house though and I can tell you that each trout species has a bunch of different strains. Rainbows have many such as kamloops, Saskatchewan, etc. and browns also have a few different strains that may vary depending on the region. I know for a fact that the great lakes region stocks at least 2 different strains of browns which includes the German brown trout strain.