Large-scale and long-term decrease in fish growth following the construction of hydroelectric reservoirs
2011 (English)In: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533, Vol. 68, no 12, 2167-2173 p.Article in journal (Refereed) Published
Hydroelectric reservoirs retain large volumes of water and have a global impact on sea level, elemental cycles, and biodiversity. Using data from a total of 90 historical and recent surveys in nine regulated and eight unregulated alpine and subalpine lakes, we show an additional large effect of reservoirs, i.e., that impoundment causes drastically decreased fish growth and thereby great negative consequences for inland fisheries in Scandinavia. Following a long period (40-65 years) after impoundment, the length and mass of Arctic charr (Salvelinus alpinus) of the single age class 4+ years was, on average, 35% and 72% lower, respectively, in impounded versus natural lakes in northern Scandinavia. The effect was stronger at higher altitudes and can be mitigated by addition of inorganic nutrients. We suggest that the decreased fish growth is a consequence of lowered ecosystem productivity, oligotrophication, caused by impoundment, resulting in erosion and loss of the littoral ecosystem as well as delayed flooding and leakage of nutrients from the riparian zone until after the growing season.
Place, publisher, year, edition, pages
2011. Vol. 68, no 12, 2167-2173 p.
IdentifiersURN: urn:nbn:se:uu:diva-169241DOI: 10.1139/F2011-131ISI: 000299190600012OAI: oai:DiVA.org:uu-169241DiVA: diva2:505923