caa a22 4500 477116612 CHVBK 20180405111624.0 cr unu---uuuuu 170330e19961101xx s 000 0 eng 10.1007/BF00000500 doi (NATIONALLICENCE)springer-10.1007/BF00000500 The effects of turbidity and vegetation on the risk of juvenile salmonids, Oncorhynchus spp., to predation by adult cutthroat trout, O. clarkii [Elektronische Daten] [Robert Gregory, Colin Levings] Synopsis: During their seaward migration, juvenile salmonids encounter structural and visual cover which varies between and within watersheds. In this study, the effects of two types of cover (turbidity and artificial vegetation) on the predation mortality of juvenile salmonids exposed to fish piscivores was investigated in outdoor concrete ponds. During experiments, adult coastal cutthroat trout, Oncorhynchus clarkii clarkii, were allowed to feed on juvenile salmonid prey — chinook salmon, O. tshawytscha, chum salmon, O. keta, sockeye salmon, O. nerka, and cutthroat trout — in separate trials. Daily instantaneous per capita predation rate was determined for each turbidity and vegetation treatment, within each trial. Mean predation rates varied between 1% and 76% daily. In the presence of cover, mean daily predation rates were 10-75% lower than those in controls (no vegetation and clear water), depending on prey species. Predation rates were significantly lower in the presence of vegetation cover and did not covary with prey size or species. The effects of turbidity were generally not significant and were not additive with the effects of vegetation. However, turbidity appeared to significantly reduce the effectiveness of vegetation as cover for juvenile chinook and sockeye salmon. We suggest that these two forms of cover do not affect risk of predation by fish piscivores to juvenile salmonids via the same mechanism. Kluwer Academic Publishers, 1996 Suspended sediment nationallicence Cover nationallicence Aquatic plants nationallicence Habitat selection nationallicence Predator avoidance nationallicence Gregory Robert Ocean Sciences Centre, Memorial University of Newfoundland, AIC 5S7, St. John's, Newfoundland, Canada aut Levings Colin Department of Fisheries and Oceans, West Vancouver Laboratory, 4160 Marine Dr., V7V 1N6, West Vancouver, British Columbia, Canada aut Environmental Biology of Fishes Kluwer Academic Publishers; http://www.wkap.nl 47/3(1996-11-01), 279-288 0378-1909 47:3<279 1996 47 10641 https://doi.org/10.1007/BF00000500 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00000500 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gregory Robert Ocean Sciences Centre, Memorial University of Newfoundland, AIC 5S7, St. John's, Newfoundland, Canada aut NATIONALLICENCE 700 1- Levings Colin Department of Fisheries and Oceans, West Vancouver Laboratory, 4160 Marine Dr., V7V 1N6, West Vancouver, British Columbia, Canada aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Kluwer Academic Publishers; http://www.wkap.nl/ 47/3(1996-11-01), 279-288 0378-1909 47:3<279 1996 47 10641 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer