and biology Habitat Zander inhabit freshwater bodies, especially large rivers and eutrophic lakes. They can tolerate brackish water and will make use of coastal lakes and estuaries. Individuals living in brackish water habitats migrate upriver, as far as for spawning. Diet Zander are carnivorous and the adults feed on smaller schooling fish. Studies around the Baltic Sea have found them to prey on the European smelt (Osmerus eperlanus), ruffe (Gymnocephalus cernua), European perch, vendace (Coregonus albula) and the common roach (Rutilus rutilus), They were also found to be cannibalistic on smaller zanders. They have also been recorded feeding on smolts of sea trout (Salmo trutta morph. trutta) and Atlantic salmon (Salmo salar). In the United Kingdom zander thrive in canals where the water is turbid due to the boat traffic and although their favoured prey in these waters is common roach they have a high impact on the populations of gudgeon (Gobio gobio). Reproduction The zander spawns over gravel in flowing water, the males defend a territory in which they dig shallow depressions in sand or gravel which are roughly across and in depth in sand or gravel. They will also nest among exposed plant roots and the eggs are laid onto these roots. The nests are normally at depths of in turbid water. Spawning takes place in pairs, at night and at daybreak. When they are spawning the female is stationary above the male's nest and the male rapidly swims around her, keeping a distance of around from the nesting depression. The male then orients itself perpendicular to the substrate and the pair swim around swiftly, releasing the eggs and sperm. The female departs after releasing her eggs. The male remains at the nest and defends it, fanning the eggs using the pectoral fins. Each female lays all of her eggs at once and only spawns once a year. The larvae are attracted to light and after they leave the nest they feed on zooplankton and small pelagic animals. They normal spawning season is in April and May, although exceptionally they may spawn from late February through to July, and the actual period depends on latitude and altitude. The determining factor is that it needs temperatures to reach before spawning starts. Life history Zander has a maximum lifespan of 17 year and they are sexually mature at 3–10 years old, with 4 years old being typical. Parasites and predators