The present study examines the composition of the diet and size-related as well as seasonal changes in the prey selection of pikeperch in large eutrophic L. Võrtsjärv. The total stomach contents of 325 pikeperch with a standard length of 5–76 cm were analysed in 1994–2005 with the goal to assess how the predation pressure of pikeperch is distributed over various prey species. The frequency of occurrence (FO), the number and restored weight of prey fish as well as the index of relative importance (IRI) and Ivlev’s selectivity index (E) were used for the description of pikeperch diet. The results of our study showed that the first prey fish for young pikeperch were mainly congeners and smelt Osmerus eperlanus (L.). With increasing body size the diet of pikeperch was enriched with ruffe Gymnocephalus cernuus (L.), perch Perca fluviatilis L., and roach Rutilus rutilus (L.). According to IRI, ruffe (IRI = 56%) was the most important prey for pikeperch in L. Võrtsjärv, while roach and perch were of second-rank importance. Bream Abramis brama (L.) was a rejected prey fish (E = – 0.9) for pikeperch, while smelt (E = 0.8) was actively selected. In comparison with data from the 1950s (Erm, V. 1961. Eesti riim- ja magevete kohade bioloogilistest ja morfoloogilistest erinevustest. In Hüdrobioloogilised uurimused, Vol. 2, pp. 289–342, Tartu), the main long-term changes in the diet of pikeperch are related to shifts in the fish community structure. Vendace Coregonus albula (L.) was the main prey (FO = 54%) for pikeperch in the 1950s, but it is absent from the recent diet. At present smelt replaces vendace in the diet of young pikeperch. Cannibalism was not observed half a century ago due to the small number of pikeperch in the lake at that time.
Ali, M. A., Ryder, R. A. & Anctil, M. 1977. Photoreceptors and visual pigments as related to behavioural responses and preferred habitats of perches (Perca spp.) and pikeperches (Stizostedion spp.). J. Fish. Res. Bd. Can., 34, 1475–1480.
Arnekleiv, J. V. & Raddum, G. 2001. Stocking Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) in rivers: diet selectivity and the effects on the macroinvertebrate community. Nord. J. Freshwater Res., 75, 109–126.
Benndorf, J. 1990. Conditions for effective biomanipulation: conclusions derived from whole-lake experiments in Europe. Hydrobiologia, 200/201, 187–203.
Bírό, P. 2001. Freshwater biodiversity: an outlook of objectives, achievements, research fields, and co-operation. Aquat. Ecosystem Health Manage., 4, 251–261.
Carpenter, S. R., Kitchell, J. F. & Hodgson, J. R. 1985. Cascading trophic interactions and lake productivity. BioScience, 35, 634–638.
Carpenter, S. R. & Kitchell, J. F. (eds) 1993. The Trophic Cascade in Lakes. Cambridge University Press, Cambridge.
Cortės, E. 1998. Methods of studying fish feeding: reply. Can. J. Fish. Aquat. Sci., 55, 2708.
Deelder, C. L. & Willemson, J. 1964. Synopsis of biological data on pike-perch Lucioperca lucioperca (Linnaeus) 1758. FAO Fish. Synop., 28, 1–58.
Densen, W. L. T. van & Grimm, M. P. 1988. Possibilities for stock enhancement of pikeperch (Stizostedion lucioperca L.) in order to increase predation on planktivores. Limnologica, 19, 45–49.
Deudero, S. & Morales-Nin, B. 2001. Prey selectivity in planktivorous juvenile fishes associated with floating objects in the western Mediterranean. Aquacult. Res., 32(6), 481–490.
Erm, V. 1961. Eesti riim- ja magevete kohade bioloogilistest ja morfoloogilistest erinevustest. In Hüdrobioloogilised uurimused, Vol. 2, pp. 289–342, Tartu.
Erm, V. 1981. Koha. Valgus, Tallinn.
Fickling, N. F. 1986. The feeding characteristics of the zander. In Proceedings of the 4th British Freshwater Fish Conference, pp. 193–202. University of Liverpool, UK.
Hacunda, J. S. 1981. Trophic relationships among demersal fishes in a coastal area of the Gulf of Maine. Fish. Bull., 79, 775–788.
Hindar, K. & Jonsson, B. 1982. Habitat and food segregation of dwarf and normal Arctic charr (Salvelinus alpius) from Vangsvatnet Lake, western Norway. Can. J. Fish. Aquat. Sci., 39, 1030–1045.
Hokanson, K. E. F. 1977. Temperature requirements of some percids and adapdations to the seasonal temperature cycle. J. Fish. Res. Bd. Can., 34, 1524–1560.
Järvalt, A., Kangur, A., Kangur, K., Kangur, P. & Pihu, E. 2004. Fishes and fisheries management. In Lake Võrtsjärv (Haberman, J., Pihu, E. & Raukas, A., eds), pp. 281–295. Estonian Encyclopaedia Publishers, Tallinn.
Järvet, A., Karukäpp, R. & Arold, I. 2004. Location and physico-geographical conditions of the catchment area. In Lake Võrtsjärv (Haberman, J., Pihu, E. & Raukas, A., eds), pp. 11–26. Estonian Encyclopaedia Publishers, Tallinn.
Kangur, A. 2000. Feeding of pikeperch, Stizostedion lucioperca (L.) in Lake Peipsi. Proc. Estonian Acad. Sci. Biol. Ecol., 49, 98–108.
Kangur, A. & Kangur, P. 1998. Diet composition and size-related changes in the feeding of pikeperch, Stizostedion lucioperca (L.) and pike, Esox lucius L. in Lake Peipsi (Estonia). Italian J. Zool., 65, 255–259.
Kangur, A., Kangur, P. & Pihu, E. 2002. Long-term trends in the ichthyocoenosis of L. Peipsi and L. Võrtsjärv (Estonia). J. Aquat. Ecosystem Health Manage., 5, 379–389.
Kangur, A., Kangur, P., Kangur, K. & Möls, T. 2007. The role of temperature in the population dynamics of smelt Osmerus eperlanus eperlanus m. spirinchus Pallas in Lake Peipsi (Estonia/Russia). Hydrobiologia (in press).
Kangur, P., Kangur, A., Kangur, K. & Möls, T. 2003. Condition and growth of ruffe Gymnocephalus cernuus (L.) in two large shallow lakes with different fish fauna and food resource. Hydrobiologia, 506–509, 435–441.
Karås, P. & Sandström, A. 2002. Effects of eutrophication on Y-O-Y freshwater fish communities in coastal areas of the Baltic. Environ. Biol. Fish., 63, 89–101.
Kitchell, J. F., Minns, M. G. J. C. K., Loftus, K. H., Greig, L. & Oliver, C. H. 1977. Percid habitat: the river analogy. J. Fish. Res. Bd. Can., 34, 1936–1940.
Lammens, E. H. R. R. 2001. Consequences of biomanipulation for fish and fisheries. FAO Fish. Circ., 952.
Lammens, E. H. R. R., Frank-Landman, A., McGillavry, P. J. & Vlink, B. 1992. The role of predation and competition in determining the distribution of common bream, roach and white bream in Dutch eutrophic lakes. Environ. Biol. Fish., 33, 195–205.
Lehtonen, H., Hansson, S. & Winkler, H. 1996. Biology and exploitation of pikeperch, Stizostedion lucioperca (L.) in the Baltic Sea area. Ann. Zool. Fenn., 33, 525–535.
Liao, H., Pierce, C. L. & Larscheid, J. G. 2001. Empirical assessment of indices of prey importance in the diets of predacious fish. Trans. Am. Fish. Soc., 130, 583–591.
Peltonen, H., Rita, H. & Ruuhijärvi, J. 1996. Diet and prey selection of pikeperch (Stizostedion lucioperca (L.)) in Lake Vesijärvi analysed with a logit model. Ann. Zool. Fenn., 33, 481–487.
Persson, A. & Brönmark, C. 2002. Foraging capacity and resource synchronization in an ontogenetic diet switcher, pikeperch (Stizostedion lucioperca). Ecology, 83, 314–322.
Pihu, E. 1993. Distribution of fish species in Estonian lakes. Proc. Estonian Acad. Sci. Ecol., 3, 181–186.
Pinkas, L., Oliphant, M. S. & Inverson, I. L. K. 1971. Food habits of albacore, bluefin tuna, and bonito in California waters. Calif. Dep. Fish Game, Fish Bull., 152, 1–105.
Popova, O. A. 1978. The role of predacious fish in ecosystems. In Ecology of Freshwater Fish Production (Gerking, S. D., ed.), pp. 215–249. Blackwell, Oxford.
Popova, O. A. & Sytina, I. A. 1977. Food and feeding relations of Eurasian perch (Perca fluviatilis) and pikeperch (Stizostedion lucioperca) in various waters of the USSR. J. Fish. Res. Bd. Can., 34, 1559–1570.
Reinart, A. & Nõges, P. 2004. Light conditions in Lake Võrtsjärv. In Lake Võrtsjärv (Haberman, J., Pihu, E. & Raukas, A., eds), pp. 141–149. Estonian Encyclopaedia Publishers, Tallinn.
Salonen, S., Helminen, H. & Sarvala, J. 1996. Feasibility of controlling coarse fish populations through pikeperch (Stizostedion lucioperca) stocking in Lake Köyliönjärvi, SW Finland. Ann. Zool. Fenn., 33, 451–457.
Skov, C., Perrow, M. R., Berg, S. & Skovgaard, H. 2002. Changes in the fish community and water quality during seven years of stocking piscivorous fish in a shallow lake. Freshwater Biol., 47, 2388–2400.
Smith, P. A., Leath, R. T. & Eaton, J. W. 1998. A review of the current knowledge on the introduction, ecology and management of zander, Stizostedion lucioperca, in the UK. In Stocking and Introduction of Fish (Cowx, I. G., ed.), pp. 209–224. Fishing News Books.
StatSoft, Inc., 2005. STATISTICA (data analysis software system), version 7.1. www.statsoft.com
Steffens, W., Geldhauser, F., Gerstner, P. & Hilge, V. 1996. German experiences in the propagation and rearing of fingerling pikeperch (Stizostedion lucioperca). Ann. Zool. Fenn., 33, 627–634.
Tuvikene, L., Kisand, A., Tõnno, I. & Nõges, P. 2004. Chemistry of lake water and bottom sediments. In Lake Võrtsjärv (Haberman, J., Pihu, E. & Raukas, A., eds), pp. 89–101. Estonian Encyclopaedia Publishers, Tallinn.
Windell, J. T. & Bowen, S. H. 1978. Methods for study of fish diets based on analysis of stomach contents. In Methods for Assessment of Fish Production in Fresh Waters (Bagenal, T., ed.), pp. 219–228. Oxford, London, Edinburgh, Melbourne.
Winfield, I. J., Tobin, C. M. & Montgomery, C. R. 1993. The fish of Lough Neagh. Part E. Ecological studies of the fish community. In Lough Neagh (Wood, R. B. & Smith, R. V., eds), pp. 451–471. Kluwer Academic Publishers.