Dibothriocephalus spp.

Dibothriocephalus spp.

The prevalence of D. ditremus varied from a minimum of 22.2 % in age-class 5 to a maximum of 60.9 % in age-class 7–8 winters, and except for age-class 3–4, the mean and median infection intensities were relatively high in all age-classes ( Table 3 View Table 3 ). The highest numbers of larvae were found in two 15 winter-old fish, with respectively 89 and 297 plerocercoids. Despite the over-dispersion of larvae, the relative density increased significantly with age (linear regression: R 2 =0.76, df=6, F=16.02, p<0.05), while the linear regression between relative density and length-class was not significant (R 2 =0.52, df=5, F=4.40, p>0.05), due to the very much higher relative density in length-class 35–39.9 cm ( Figure 4 View Figure 4 ). A single specimen of D. dendriticus was identified as a new species in the lake ( Table 3 View Table 3 ).