Fish predation pressure on zooplankton in a large northern temperate lake : impact of adult predators versus juvenile predators
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Kuupäev
2018
Kättesaadav alates
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Estonian Academy Publishers
Abstrakt
In recent decades, a marked decrease in planktivorous fish (Osmerus eperlanus eperlanus m. spirinchus Pallas and
Coregonus albula (L.)) in Lake Peipsi has stimulated research into the potential effect of fish predation on zooplankton.
The abundance of planktivorous fish and the abundance and biomass of zooplankton were studied from 1986 to 2014, and the diet
of plankton-eating fish was analysed from 2007 to 2013. A linear regression model was used to establish possible trends in
the zooplankton assemblages (biomass, abundance, mean weight of individuals) and in the abundance of zooplankton-eating fish.
The ANOVA test was used to evaluate differences in the zooplankton assemblages and in fish consumption in the years with large
and small fish cohorts. Despite the collapse of the smelt and vendace populations, the abundance of plankton-eating fish remained
high due to an increase in the abundance of juvenile fish. Fish juveniles consumed as much as or even more zooplankton than
adult planktivores. Since 1986, a significant decrease was observed in the cladoceran and copepod biomass and in the mean body
weight of cladocerans. Large cladocerans such as Leptodora kindtii (Focke) and Bythotrephes longimanus Leydig were rare in
zooplankton samples and the biomass of Bosmina spp. decreased. Changes in the structure of the zooplankton community were
most likely caused by the feeding of juvenile fish as the calculated consumption by fish was high, especially in years with
particularly large fish cohorts.
The research was supported by the Estonian target financed project SF0170006s08. We gratefully acknow- ledge Ester Jaigma for the linguistic editing of the manuscript, Marina Haldna for assistance in statistical analyses, and Dr Peeter Kangur for data collection. The publication costs of this article were covered by the Estonian Academy of Sciences.
The research was supported by the Estonian target financed project SF0170006s08. We gratefully acknow- ledge Ester Jaigma for the linguistic editing of the manuscript, Marina Haldna for assistance in statistical analyses, and Dr Peeter Kangur for data collection. The publication costs of this article were covered by the Estonian Academy of Sciences.
Kirjeldus
Märksõnad
planktivorous fish, zooplankton, diet of juvenile fish, size of fish cohorts, top-down effect of fish, articles