caa a22 4500 445891890 CHVBK 20180317145619.0 cr unu---uuuuu 170323e20110201xx s 000 0 eng 10.1007/s10750-010-0393-6 doi (NATIONALLICENCE)springer-10.1007/s10750-010-0393-6 Diet patterns and ontogenetic diet shift of pikeperch, Sander lucioperca (L.) fry in lakes Peipsi and Võrtsjärv (Estonia) [Elektronische Daten] [Kai Ginter, Külli Kangur, Andu Kangur, Peeter Kangur, Marina Haldna] Pikeperch is a major predator in the pelagic zone of eutrophic waters, such as the large north-temperate lowland lakes Võrtsjärv (Estonia) and Peipsi (Estonia/Russia). The size and structure of the pikeperch population is strongly influenced by their success at the juvenile stage. Therefore, we investigated the diet and prey selection of pikeperch fry caught in the ice-free period in lakes Peipsi and Võrtsjärv in 2007 and 2008. We analysed the stomach contents of 635 pikeperch from Lake Peipsi and 202 pikeperch from Lake Võrtsjärv, and compared our findings with similar data from the 1950s (Erm, About Biological and Morphological Differences of Pikeperch. Hydrobiological Researches II (in Estonian), 1961). Analysing 4-20cm long fry, we studied differences in prey size, seasonal diet patterns and the ontogenetic diet shift. In both lakes, 0+ pikeperch feed mostly on large predatory zooplankters. However, in Lake Peipsi the stomach content weight and the average number of food items in stomach were higher, and the food spectrum was wider than in Lake Võrtsjärv. There was also a difference in the type of food that dominated fry's stomach content (calculated by weight) in the two lakes. In Lake Peipsi, chironomids larvae, as well as zooplankters Daphnia galeata and Bythotrephes longimanus dominated, while in Lake Võrtsjärv zooplankters Mesocyclops leuckarti and Leptodora kindti. Seasonal analysis showed that cladocerans dominated in pikeperch fry stomach content in summer and at the beginning of September, but copepods were dominant in autumn and spring. In contrast to the studies carried out from 1952 to 1958 (Erm, About Biological and Morphological Differences of Pikeperch. Hydrobiological Researches II (in Estonian), 1961), the shift from planktivory to piscivory at the end of the first growing season was hardly ever observed during our investigation. We believe this is due to the lack of suitable prey fish as there was a collapse of the smelt, Osmerus eperlanus (L.), population in both lakes. The transition of pikeperch from planktivory to piscivory was delayed till the next summer. Springer Science+Business Media B.V., 2010 0+ Pikeperch nationallicence Stomach content analyses nationallicence Ontogenetic diet shift nationallicence Feeding patterns nationallicence Large lakes nationallicence Ginter Kai Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut Kangur Külli Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut Kangur Andu Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut Kangur Peeter Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut Haldna Marina Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut Hydrobiologia Springer Netherlands 660/1(2011-02-01), 79-91 0018-8158 660:1<79 2011 660 10750 https://doi.org/10.1007/s10750-010-0393-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10750-010-0393-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ginter Kai Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut NATIONALLICENCE 700 1- Kangur Külli Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut NATIONALLICENCE 700 1- Kangur Andu Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut NATIONALLICENCE 700 1- Kangur Peeter Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut NATIONALLICENCE 700 1- Haldna Marina Centre for Limnology, Estonian University of Life Sciences, 61117, Rannu, Tartumaa, Estonia aut NATIONALLICENCE 773 0- Hydrobiologia Springer Netherlands 660/1(2011-02-01), 79-91 0018-8158 660:1<79 2011 660 10750 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer