The trophic role of Cyphocharax voga (Hensel, 1869) according to habitat foraging and diet analysis in turbid shallow lakes

GONZALEZ SAGRARIO MA; FERRERO, L

FUNDAMENTAL AND APPLIED LIMNOLOGY

E SCHWEIZERBARTSCHE VERLAGS

Lugar: Stuttgart; Año: 2013 vol. 183 p. 75 - 88

1863-9135

Detritivory is a widespread strategy that has been associated to shallow, warm and productive systems. Eutrophic and hypereutrophic lakes can be dominated by an assemblage of detritivorous fish species. The trophic role of the pelagic fish Cyphocharax voga in two temperate turbid shallow lakes is analyzed through the study of its diet and foraging area. The results showed that C. voga consumed detritus, zoobenthos and zooplankton (95.77%, 4.11% and 0.12 % of total ash free dry mass ingested, respectively). Benthic invertebrates were the most abundant organisms ingested, representing the 93 % of the total biomass. In particular, Leydigia louisi, ostracods and harpacticoid copepods contributed most in abundance and biomass. Pelagic preys, represented mainly by Bosmina (Neobosmina) huaronensis, constituted the 7 % of the total biomass consumed by fish. Prey availability was determined in the open and littoral areas and in the lake bottom. C. voga showed a selectivity for crustaceans from the lake bottom. These evidences and the high consumption of detritus indicate that C. voga is exploiting the benthic food webs and thus can be considered a detritivorous species. This strategy seems suitable in turbid lakes (20-30 cm Secchi disc depth) where prey detection for visual predators is constrained. Moreover, as C. voga attains a high biomass in warm temperate eutrophic shallow lakes of South America, it might be contributing to the linkage of benthic and pelagic pathways, being detritus and benthic invertebrates a subsidy for the pelagic food web.