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Does roach behaviour differ between shallow lakes of different environmental state?
Author(s) -
Jacobsen L.,
Berg S.,
Jepsen N.,
Skov C.
Publication year - 2004
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.0022-1112.2004.00436.x
Subject(s) - rutilus , diel vertical migration , noon , biology , predation , dusk , shore , fish <actinopterygii> , waves and shallow water , ecology , predator , cyprinidae , fishery , oceanography , geology , atmospheric sciences
The diel activity levels and spatial distribution of roach Rutilus rutilus differed markedly between two shallow lakes of different environmental state. The movements of roach (12–25 cm L T ), with surgically implanted mini‐radio transmitters, were monitored regularly during several 48 h tracking sessions in a clearwater and in a turbid lake. In both lakes, the roach in general were most active during dawn and dusk and least active during the night. Activity level in midsummer was lowest around noon in the clear lake and high around noon in the turbid lake. In summer, roach in the clear lake stayed passively in a restricted area of water lilies during the day and moved into the central part of the lake during the night. In the turbid lake, roach were dispersed all over the lake during the day and moved close to the shoreline at night. Predator : prey fish ratios did not differ in the two lakes, however the observed behaviour of roach in the clearwater lake may be explained by a larger predation pressure from fish and birds, both being favoured in the clear water.