Individual characteristics: (a), (b) catch, (c), (d) abundance, (e), (f) standard length (L _S), and (g), (h) age, of 0+ Sander lucioperca trawl catches in the Římov Reservoir in (a), (c), (e), (g) 2007 and (b), (d), (f), (h) 2008. Grey lines indicate linear relationship between observed values and sampling time. Median values (thick lines), upper and lower quartiles (boxes), maximum and minimum values (whiskers), and outliers (dots) are shown.