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Field and experimental evidence of the effect of Jenynsia multidentata , a small omnivorous–planktivorous fish, on the size distribution of zooplankton in subtropical lakes
Author(s) -
IGLESIAS CARLOS,
MAZZEO NÉSTOR,
GOYENOLA GUILLERMO,
FOSALBA CLAUDIA,
TEIXEIRA DE MELLO FRANCO,
GARCÍA SOLEDAD,
JEPPESEN ERIK
Publication year - 2008
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.2008.02007.x
Subject(s) - zooplankton , ecology , copepod , biology , omnivore , predation , piscivore , daphnia , eutrophication , fishery , plankton , crustacean , predator , nutrient
Summary 1. Small cladocerans, copepod nauplii and rotifers often dominate the zooplankton community in tropical and subtropical lakes. This is probably because of high predation pressure by small omnivorous–planktivorous fish, but experimental evidence is scarce. 2. This study used two approaches to test the effect of the small omnivorous–planktivorous fish species Jenynsia multidentata , which is frequently abundant in (sub)tropical eutrophic lakes in South America, on the size distribution of zooplankton. In Lake Blanca (Uruguay), which lacks any piscivores, we sampled seasonally for both fish and zooplankton. We also conducted an outdoor mesocosm experiment with treatments containing or lacking J. multidentata . 3. Together, the empirical and experimental data suggest that J. multidentata predation plays an important role in modulating the size structure of the zooplankton community in subtropical lakes. In the absence of J. multidentata , stocked large‐sized zooplankters like Daphnia obtusa were abundant in the experiments, while small‐sized zooplankton dominated in the presence of fish, as they did in the lake itself from spring to the end of the season.