Restoring the Vindel River, Sweden for Atlantic Salmon and Brown Trout
Gustav Hellström, Christer Nilsson, Stig Westbergh, Daniel Palm, Kjell Leonardsson, Daniel Holmqvist, Stefan Ågren, Johanna Gardeström, Anders Alanärä, and Hans Lundqvist
Abstract.—The Vindel River (Vindelälven), Sweden, is 450 km long with a mean annual discharge of 190 m3/s and runs through sparsely populated areas in northern Sweden, joining the Ume River near the Baltic Sea. A severe decline in Atlantic Salmon Salmo salar and Brown Trout S. trutta during the past century was caused by (1) intense timber-floating activities starting in the mid-1800s, which degraded stream habitat; (2) hydropower development in the early 1900s, which limited or blocked upstream migration; and (3) an expanded coastal/ocean fishery after 1950, which overharvested anadromous populations. Restoration efforts during the 1970s and 1980s failed due to low efficacy of stocking programs and insufficient habitat restoration. A legislative reform to unify the fishery right owners (FROs) along the river helped initiate restoration efforts in the late 1990s, focusing on improving fish migration past a hydropower station and restoring degraded habitat. Sweden’s membership in the European Union made large funding for restoration projects possible. The number of returning Atlantic Salmon increased significantly after migration conditions improved around the hydropower station and with stricter regulations on the offshore fishery. Successful habitat restoration was based upon gaining trust from landowners and FROs via extensive communication to gain access to their land. Restoration work was adaptive and experiences gained were incorporated into restoration guidelines. Involvement of universities, as a provider of expertise and as an unbiased interpreter of data, provided support to legal processes and when evaluating restoration measures. During the course of the restoration work, managers learned that stocking often did not produce satisfactory results. By studying historical documents from the timber-floating era, managers learned that the scope of modifications of the tributaries had been much greater than previously thought and that habitat restoration needed to be extensive. In many tributaries, the number of juvenile Brown Trout increased significantly after habitat restoration, sometimes dramatically exceeding expectations, which made the managers question the validity of established production estimates for northern boreal streams. The experience and knowledge gained from the Vindel River restoration served as the catalyst for many other major restoration projects in rivers emptying into the Baltic Sea.