Effect of filter-feeding fish silver carp on phytoplanktonspecies and size distribution in surface water: A fieldstudy in water work
Hua Ma , Fuyi Cui , Zhiquan Liu , Zhenqiang Fan , Wenjie He , Peijun Yin
DOI:
Received May 22, 2009,Revised August 27, 2009, Accepted , Available online
Volume 22,2010,Pages 161-167
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Silver carp were introduced into the pre-sedimentation pond to control excessive phytoplankton in raw water. The e ectiveness of
the filter-feeding silver carp on phytoplankton control and the e ect of silver carp on phytoplankton community were investigated.
The results showed that Microcystis could be e ectively removed by silver carp stocked in the pre-sedimentation pond, and
simultaneously, the concentration of single-cell phytoplankton increased obviously. The di erence in phytoplankton species and singlecell
phytoplankton size between in the water and in the gut of silver carp indicated that phytoplankton smaller than 5 m, such as
Chamydomonas and Platymonas, were almost not be filtered by silver carp, phytoplankton with the size between 5 and 20 m could
be partly filtered, and large size phytoplankton, mainly colony-forming Microcystis could be filtered almost completely. These filterfeeding
characteristics directly caused the phytoplankton size distribution biased toward miniaturization. Therefore, this biological
treatment using silver carp could be applied only to deal with groups of Microcystis-dominated eutrophic water, and was not appropriate
in water bodies where single-cell micro phytoplankton were dominant. Especially when silver carp are used in water treatment, a
cautious attitude should be taken based on the evaluation of phytoplankton biomass and species structure features in raw water.
