The growth of perch, Perca fluviatilis L., in small Finnish lakes at different stages of acidification

• Published in: Annales zoologici fennici 1988-01, Vol.25 (3), p.209-219
• Main Authors: Raitaniemi, Jari, Rask, Martti, Vuorinen, Pekka J.
• Format: Article
• Language: English
• Subjects: Acidification; Agnatha. Pisces; Aluminum; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Autoecology; Biological and medical sciences; Ecology, faunistics; Freshwater; Freshwater ecology; Freshwater fishes; Fundamental and applied biological sciences. Psychology; Lake water; Lakes; Limnology; Perca fluviatilis; Population ecology; Population growth; Vertebrata
• ISSN: 0003-455X; 1797-2450

The growth of perch (Perca fluviatilis L.) was studied in 16 oligotrophic lakes at different stages of acidification. The lakes were divided into three groups according to their pH: I Very acid lakes (6 lakes, pH < 5), II Moderately acid lakes (5 lakes, 5 ≤ pH < 6) and III Circumneutral lakes (5 lakes, pH ≥ 6). Perch was the only fish species caught from most of the very acid and moderately acid lakes. The mean weights of the perch were higher and numbers/catch smaller in very acid lakes than in other lakes. The perch grew faster in very acid lakes than in two other acidity groups, where the growth rates did not differ from each other. The most probable reason for the rapid growth in the most acid lakes was increased availability of food due to thinning of the perch populations as a consequence of acid induced reproduction failures. An exception was Lake Hauklampi (pH 4.8), where the perch did not grow as fast as in the other very acid lakes. This may have been due to the stress attributable to a high total aluminium content in the water (400 μg/l).