The density and mean size of 0 + pikeperch (Sander lucioperca) were studied in late summer in 2004–2017 in clay-turbid and eutrophic Lake Tuusulanjärvi in southern Finland. Hydroacoustics and simultaneous experimental trawling were used to estimate the density of 0 + pikeperch. In some autumns, 0 + pikeperch was the most abundant species in the pelagic fish assemblage. However, the annual amplitude of pikeperch density was extremely high (1,300 - 19,900 individuals ha⁻¹). The density and size variations of 0 + pikeperch were analysed in relation to air temperature sums and degree days. Unexpectedly, the density of 0 + pikeperch showed no correlation with the air temperature sums or degree days, but both the mean length and weight of 0 + pikeperch correlated positively with these temperature variables. The highest correlation coefficients between mean size and temperature were found with temperature sums over 10 °C and degree days over 5 °C. The correlation between density and condition of 0 + pikeperch was negative but non-significant. The high density of 0 + pikeperch in some autumns suggests that pikeperch may play a central role in the pelagic food web in eutrophic lakes – not only as a predator of planktivores but also by its own planktivory.

2004-2017 年夏末，在芬兰南部粘土混浊和富营养化的 Tuusulanjärvi 湖中研究了 0 + pikeperch ( Sander lucioperca ) 的密度和平均大小。使用水声学和同时实验拖网来估计 0 + pikeperch 的密度。在某些秋季，0 + pikeperch 是远洋鱼类群落中最丰富的物种。然而，梭鲈密度的年幅度非常高（1,300 - 19,900 只 ha ^-1）。分析了 0 + pikeperch 的密度和大小变化与气温总和和度日的关系。出乎意料的是，0 + pikeperch 的密度与气温总和或度日无关，但 0 + pikeperch 的平均长度和重量都与这些温度变量呈正相关。在温度总和超过 10°C 和度数超过 5°C 时，发现平均大小和温度之间的相关系数最高。0 + pikeperch 的密度与条件之间的相关性为负但不显着。某些秋季 0 + 梭鲈的高密度表明梭鲈可能在富营养化湖泊的中上层食物网中发挥核心作用——不仅作为浮游动物的捕食者，而且还作为其自身的浮游动物。