Aquatic Ecology

, Volume 33, Issue 2, pp 193–204

Experimental study of the impacts of silver carp on plankton communities of eutrophic Villerest reservoir (France)

  • Isabelle Domaizon
  • Jean Devaux

DOI: 10.1023/A:1009984713183

Cite this article as:
Domaizon, I. & Devaux, J. Aquatic Ecology (1999) 33: 193. doi:10.1023/A:1009984713183


We examined the impact of five silver carp biomass levels (0, 8, 16, 20, and 32 g m−3) on plankton communities and water quality of Villerest eutrophic reservoir (France). We realized the experiments using outdoor mesocosms. The presence of silver carp led to changes in zooplankton and phytoplankton assemblages. High fish biomass strongly reduced cladoceran abundance (through predation). Silver carp inefficiently grazed down particles < 20 μm. More importantly, however, the suppression of herbivorous cladocerans resulted in the increase of small size algae which were relieved from grazing and benefit from high nutrient concentrations.

In contrast, in mesocosms without fish, the dominance of cladocerans (mainly Daphnia) controlled small size algae and probably also larger size algae (colonial chlorophytes, cyanobacteria). Thus, the Secchi disc transparency increased markedly. Through cascade effects, the modification of grazers communities led to changes in the utilization patterns of the added nutrients by phytoplankton communities. In high fish biomass treatments, nutrients were more efficiently accumulated into particulate fractions compared with no-fish and low-fish biomass treatments that were characterized by higher dissolved nutrients concentrations. Zooplankton was an essential source of food for silver carp. The productivity of zooplankton sustained a moderate silver carp biomass (up to 16 g m−3). In the presence of the highest fish biomass, the productivity of zooplankton was not large enough and silver carps fed on additional phytoplankton. Although mesocosms with high fish biomass were characterized by a slight cyanobacteria development compared with other fish mesocosms, silver carp was not effective in reducing cyanobacteria dominance.

biomanipulationeutrophic reservoirmesocosmphytoplanktonsilver carpzooplankton

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Isabelle Domaizon
    • 1
  • Jean Devaux
    • 1
  1. 1.Laboratoire de Biologie Comparée des Protistes, UPRES-A CNRS 6023Université Blaise Pascal Clermont IIAubière CedexFrance (E-mail