INVESTIGADORES
O'FARRELL Ines
artículos
Título:
Hydrology driven factors might weaken fish predation effects on zooplankton structure in a vegetated warm temperate floodplain lake
Autor/es:
CHAPARRO, G.; FONTANARROSA M.S; CATALDO, D.; O'FARRELL I.
Revista:
HYDROBIOLOGIA
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2014 p. 1 - 16
ISSN:
0018-8158
Resumen:
Fish predation on microcrustaceans is of
key importance for dominance of small zooplankters
in warm shallow lakes, yet its role in floodplain
environments remains poorly explored. We studied
seasonal and spatial variations of the abundance, diet
composition and feeding selectivity of small omnivorous?
planktivorous fish in relation to zooplankton at
different habitats in a floodplain lake of the Lower
Parana´ River. Fish catches were very high in spring
and summer and scarce in autumn and winter, and
their distribution varied among habitats in response to
changes in refuge provision and oxygen concentration.
Fish diet comprised zooplankton, phytoplankton and
detritus, except in summer when Cyanobacteria prevailed;
in general, cyclopoid copepods and cladocerans
were positively selected. Macrozooplankton
biomass was the highest in spring when calanoid
copepods dominated, probably because their fast
swimming velocity enabled their escape from predators.
Lower macrozooplankton biomass in summer
with low waters, was likely caused by harmful effects
of Cyanobacteria or elevated salinity, while washingout
or dilution processes may explain macrozooplankton
scarcity during cold seasons under low fish
predation pressure. Our results indicate that in floodplain
lakes, factors affected by or related to hydrology
(salinity, Cyanobacteria development, dilution and
washing-out processes) may have stronger influence
than predation on zooplankton structure.