Field and experimental evidence of the effect of Jenynsia multidentata, a small omnivorous–planktivorous fish, on the size distribution of zooplankton in subtropical lakes

Abstract

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.

Fish but Not Macroinvertebrates Promote Trophic Cascading Effects in High Density Submersed Plant Experimental Lake Food Webs in Two Contrasting Climate Regions

“…By contrast, in the fish treatments, a cascading effect was revealed by a major reduction of the zooplankton grazing potential and a significant increase in phytoplankton biomass in both climatic zones. Our findings confirm the occurrence of a fish predation-driven structure of zooplankton [2], as suggested also in previous works in subtropical, e.g., [19,26,32,[56][57][58][59][60], temperate, e.g., [61][62][63][64], and even sub-polar systems [65,66].…”

Crustacean zooplankton communities in 13 lakes of Yunnan-Guizhou plateau: Relationship between crustacean zooplankton biomass or size structure and trophic indicators after invasion by exotic fish

“…Currie et al (1999) found that the presence of planktivorous fish also resulted in a significant relationship between copepods and cladocerans. Our results supply more comprehensive evidence to support the idea that copepods were more resistant to the predation of planktivorous fish (Schulz et al, 2003;Iglesias et al, 2008) and the predation of planktivorous fish on cladocerans would result in a decrease of water quality (Benndorf et al, 2002;Radke and Kahl, 2002). Therefore, invasion of exotic fish and consistent high production of these fish in lakes of Yunnan-Guizhou plateau have a negative effect on water quality.…”

A comunidade fitoplanctônica nas represas Billings e Guarapiranga (região metropolitana de São Paulo)

“…Accordingly, Other parameters that were not included in our study, such as predation by planktivorous fishes, probably also affected the spatial and temporal distribution of zooplankton species, especially cladocerans (IGLESIAS et al, 2008). As their population development is slower, cladocerans are more likely to be controlled by a top-down process while rotifer life histories are strongly influenced by bottom-up mechanisms (WALZ, 1997).…”