Influence of visual conditions on foraging and growth of juvenile fishes with dissimilar sensory physiology |
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Authors: | L. Ljunggren,&dagger &Dagger A. Sandströ m,§ |
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Affiliation: | Institute for Coastal Research, National Board of Fisheries, Box 109 SE-74071, Öregrund, Sweden; , Department of Aquaculture, SLU, SE-901 83 Umeå, Sweden; , Department of Natural and Environmental Sciences, Mid-Sweden University SE-831 25 Östersund, Sweden; and Department of Biology, Åbo Akademi University, FI-20500, Turku, Finland |
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Abstract: | The influence of turbidity on foraging and growth of young-of-the-year (YOY) of two percid species with relatively dissimilar sensory physiology, perch Perca fluviatilis and pikeperch Sander lucioperca was tested. A littoral mysid, Neomysis integer , was used as prey. Functional response was investigated indoors at two levels of turbidity, 3 NTU (clear) and 25 NTU (turbid). Growth and consumption rate were studied both during day and night in outdoor experiments at similar turbidity levels. Pikeperch were not affected by turbid conditions in either of the experiments. Foraging of perch, on the other hand, was significantly negatively affected by higher turbidity in the functional response experiments and during the night-time in the outdoor experiments. As opposed to pikeperch, consumption rates of perch decreased markedly during nights. Perch also grew more slowly in the treatments with turbid water. The dissimilar reactions of the two species indicate that sensory physiological adaptations and foraging behaviour are important factors that partly can explain disparate reactions of YOY fishes to the level of turbidity. |
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Keywords: | foraging growth perch pikeperch turbidity visual |
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