| Abstract | Planktivorous and benthivorous fish have been documented to influence the density and size structure of their prey communities in lakes. We hypothesized that piscivorous fish modify their prey fish communities in the same way and sought to find evidence for such predation effects from a comparison across 356 lakes located in nine European ecoregions.Wecategorized individual fish as being piscivore, nonpiscivore, or prey of piscivores, depending on species and individual size. We calculated piscivore, nonpiscivore, and piscivore prey densities, respectively, and fit linear abundance size spectra (SS) on lake-specific piscivore, nonpiscivore, and piscivore-prey size distributions. Multiple linear regressions were calculated to quantify the effect of piscivore density and SS slopes on nonpiscivore and piscivore-prey densities and SS slopes by accounting for potentially confounding factors arising from lake morphometry, productivity, and local air temperature. Piscivore density correlated positively with piscivore-prey density but was uncorrelated with density of nonpiscivores. Across a subset of 76 lakes for which SS slopes of piscivores were statistically significant, SS slopes of piscivores were uncorrelated with SS slopes of either nonpiscivores or piscivore prey. However, densities of piscivores, nonpiscivores, or piscivore prey were a significant negative predictor of SS slopes of the respective groups. Our analyses suggest that direct predation effects by piscivorous fish on density and size structure of prey fish communities are weak in European lakes, likely caused by low predator-prey size ratios and the resulting size refuges for prey fish. In contrast, competition may substantially contribute to between-lake variability in fish density and size. |
| Text | 386478 2016 10.1139/cjfas 2015 0034 Scopus 2 s2.0 84962106185 Fish lakes Effects of fish predation on density and size spectra of prey fish communities in lakes Mehner T.; Keeling C.; Emmrich M.; Holmgren K.; Argillier C.; Volta P.; Winfield I.J.; Brucet S. Leibniz Institute of Freshwater Ecology and Inland Fisheries, Department of Biology and Ecology of Fishes, Berlin, 12587, , Germany; Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Freshwater Research, Drottningholm, , , Sweden; Swedish University of Agricultural Sciences, Department of Aquatic Resources, Institute of Freshwater Research, Drottningholm, , , Sweden; Irstea UR HYAX, centre d Aix en Provence, Aix en Provence, , France; CNR Institute of Ecosystem Study, Verbania Pallanza, , Italy; Lake Ecosystems Group, Centre for Ecology Hydrology, Lancaster, , United Kingdom; University of Vic Central University of Catalonia, Aquatic Ecology Group, BETA Technology Centre, 17 Vic, Catalonia, , Spain; Aarhus University, Department of Bioscience, Aarhus, , Denmark; Catalan Institution for Research and Advanced Studies, ICREA, Barcelona, 08010, , Spain Planktivorous and benthivorous fish have been documented to influence the density and size structure of their prey communities in lakes. We hypothesized that piscivorous fish modify their prey fish communities in the same way and sought to find evidence for such predation effects from a comparison across 356 lakes located in nine European ecoregions.Wecategorized individual fish as being piscivore, nonpiscivore, or prey of piscivores, depending on species and individual size. We calculated piscivore, nonpiscivore, and piscivore prey densities, respectively, and fit linear abundance size spectra SS on lake specific piscivore, nonpiscivore, and piscivore prey size distributions. Multiple linear regressions were calculated to quantify the effect of piscivore density and SS slopes on nonpiscivore and piscivore prey densities and SS slopes by accounting for potentially confounding factors arising from lake morphometry, productivity, and local air temperature. Piscivore density correlated positively with piscivore prey density but was uncorrelated with density of nonpiscivores. Across a subset of 76 lakes for which SS slopes of piscivores were statistically significant, SS slopes of piscivores were uncorrelated with SS slopes of either nonpiscivores or piscivore prey. However, densities of piscivores, nonpiscivores, or piscivore prey were a significant negative predictor of SS slopes of the respective groups. Our analyses suggest that direct predation effects by piscivorous fish on density and size structure of prey fish communities are weak in European lakes, likely caused by low predator prey size ratios and the resulting size refuges for prey fish. In contrast, competition may substantially contribute to between lake variability in fish density and size. 73 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 84962106185 partnerID=q2rCbXpz Articolo in rivista National Research Council Canada. 0706 652X Canadian journal of fisheries and aquatic sciences Print Canadian journal of fisheries and aquatic sciences Print Can. j. fish. aquat. sci. Print Canadian journal of fisheries and aquatic sciences. Print Journal canadien des sciences halieutiques et aquatiques Print pietro.volta VOLTA PIETRO |
