Fig. 2.

Abundance of the Trichodina spp. on an arbitrary scale (0 absent, 1 1–3, 2 4–10, 310–20, 4 >21 individuals per slide) at different sampling locations during the study. Given are median abundance (squares) with 25–75% percentiles (boxes in grey) and 10–90% percentiles (whiskers). Prevalences [%] are indicated below the box plots. The sampling periods, shown below the prevalences, are identified by month and year (Apr April, Sept September, Oct October). Order of abundance observed among sites is given at the top of the graph for each sampling period. In parenthesis: additional differences observed for prevalences. E Elbe, O Outer Eider, H Helgoland, S Spiekeroog, I Inner Eider. The numbers of flounder evaluated during the sampling periods are given in Table 1