Recovery of the Perch (Perca Fluviatilis) in an Acidified Lake and Subsequent Responses in Macroinvertebrates and the Goldeneye (Bucephala Clangula)

• Published in: Water, air, and soil pollution Vol. 130; no. 1-4; pp. 1367 - 1372
• Main Authors: Rask, M, Poeysae, H, Nummi, P, Karppinen, C
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01-08-2001
• Subjects: Acid deposition; Acidity; Aquatic birds; Aquatic organisms; Bucephala clangula; Environmental monitoring; Finland, Vaehae Valkjaervi L; Fish; Freshwater; Lakes; Macroinvertebrates; Perca fluviatilis; Population number; Predation; Studies; Water quality; Finland; Finland, South
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1023/A:1013967604076

The perch population of Lake Vaehae Valkjaervi, a two hectare clear-water lake in southern Finland, decreased due to acid precipitation during the 1980s. During the early 1990s a decrease in acidic deposition resulted in slight improvement of water quality of the lake. This was followed by recovery of the reproduction of perch starting in 1991. A mark and recapture experiment in spring 1995 indicated a hundred fold increase in the population size of perch in a four year period. A decrease in the abundance of aquatic invertebrates was recorded during 1989-1996. This decrease well coincided with the recovery of the perch population, suggesting that increased predation by fish was responsible for the decrease. The occurrence of goldeneye young also dropped in L. Vaehae Valkjaervi since 1993. This was thought to be due to increased food competition with perch.