to be built), Byälven and its tributaries (which went extinct in the 1950s due to the construction of the power plant in Jössefors and no obligations to build fish ladders) and in Borgviksån (in 1939, a new power station was built by the upper falls of Borgviksån, without a fish ladder being built, blocking access to upstreams spawning grounds). Large and unique populations of lake brown trout found in Lake Vänern, that also went extinct, include stocks from the drainage systems coming via Norsälven, Byälven, Upperudsälven, Åmålsån, Borgviksån, Lidan, and at the lakes outlet the rapids near Vargön (as a very special type of downstream spawning trout locally named “Vänerflabben”). Only Gullspångsälven and Tidan still have confirmed yet small self-sustaining migratory salmonid stocks left remaining coming from Vänern (Ros, 1981). The stocks in Klarälven are artificially maintained via human transport to spawning grounds above 9 power stations and the migratory brown trout population here is almost extinct. Nevertheless, most of these once unique subspecies of landlocked salmon once found in Lake Vänern have forever disappeared from the face of the earth due to man made incursions. There are also other species of salmonids (brown trout, Arctic char and grayling) found in the connecting lakes, rivers and streams. Some of these isolated lake brown trout strains are very large in size and genetically unique, although also today being severely threatened (Ros, 1981). Negative environmental changes in the waters holding the juvenile stages of salmon (which have specific demands of clean and running water in their "pre-lake stage" that lasts 1–3 years) have had an undesired effect on the production of natural smolts now entering the lake. This is especially true in the Gullspång River - where it is believed that less than 1% of the natural smolt producing habitat remains in the surrounding watershed drainage system (Ros, 1981). Both salmon and trout also heavily rely upon being able to reach their spawning grounds, which is presently severely limited after the construction of numerous dams in both river systems. Other factors contributing to habitat deterioration include forestry & logging, agriculture, acidification of waters, pollution, road construction, fishing pressure, predators (mostly mink and cormorant - which are both accidentally introduced species) and climate change ([Nordberg 1977] and [Piccolo et al. 2012]). The overall production of natural smolts is today thereby thought to be well under 10% of Lake Vänerns previous output and capacity