The Return of the Salmon
Source: Water, Air, and Soil Pollution, Volume 130, Numbers 1-4, August 2001 , pp. 1349-1354(6)
Abstract:The Atlantic salmon population in the River Otra, southern Norway was lost during the 1960's due to acid rain and industrial and municipal pollution. The industrial and municipal pollution sources were sanitized by 1995. A concurrent reduction in acid deposition has during the last 10 years raised pH from 5.2 to 5.7 and reduced inorganic monomeric Al from 71 to 28µg Al L^−1 above the industrial area. The water quality improvement resulted in salmon fry again being caught from 1995. Physiological measurements (blood parameters and seawater tolerance) performed on smolts of Atlantic salmon exposed within the river during the spring of 1999 suggests that the smolts were fully smoltified and seawater tolerant, despite having moderate gill morphological changes and having moderate high gill Al concentrations (70–80 µg Al g^−1 dw). The smolt quality measured suggests that the river again can support a native salmon population, provided no negative change in water quality. Winter episodes and acid tributaries within the watershed can, however, offset the recovery process.
Document Type: Regular Paper
Affiliations: 1: Norwegian Institute for Water Research, PO Box 173, Kjelsås, N-0411 Oslo, Norway e-mail: email@example.com 2: Norwegian Institute for Water Research, PO Box 173, Kjelsås, N-0411 Oslo, Norway 3: Norwegian School of Veterinary Science, PO Box 8146, N-0033 Oslo, Norway
Publication date: 2001-08-01