0000000000142124
AUTHOR
A Niemi
Fish community responses to pulp and paper mill effluents at the southern Lake Saimaa, Finland.
Abstract The fish community in sublittoral and profundal waters, at stony shores, and densities of vendace larvae were studied in the southern Lake Saimaa, Finland. The objective was to investigate the possible recovery of fish populations after modernizations at the pulp and paper mills discharging into the lake. Sublittoral and profundal waters were studied by gill net trial fishings, stony shores by electrofishing, and vendace larvae by beach seine. The research area was divided in a polluted (0.5–4.0% effluent), an intermediate (0.1–0.5%) and a ‘clean’ reference area. The fish community in sublittoral and profundal waters in the lake was dominated (>60%) by perch and roach. Relative abu…
The influence of food competition and host specificity on the transmission of Triaenophorus crassus (Cestoda) and Cystidicola farionis (Nematoda) to Coregonus lavaretus and Coregonus albula (Pisces:Coregonidae) in Finland.
Abstract As a superior competitor for planktonic food, vendace ( Coregonus albula ), when abundant, is expected to displace whitefish ( Coregonus lavaretus ) from feeding on plankton and to force it to rely more on benthic food. The predicted result would be a reduced abundance of the copepod-transmitted cestode Triaenophorus crassus in whitefish, but an increase in the abundance of the nematode Cystidicola farionis transmitted via benthic amphipods. We studied the occurrence of both parasites in whitefish during 1991–1996 in three interconnected areas at Lake Saimaa, Finland, where the densities of the vendace stocks varied due to natural fluctuation in year-class strengths. In accordance …