and largemouth bass; b) species with a feeding strategy specialised on one food category. The fish species included in this stenophagous group varied seasonally: in winter and spring it included nase (detritivorous) and roach, which preyed on cladocerans almost exclusively. In summer, the nase was the only species that remained in this group, whereas roach was grouped together with barbel, mirror carp and white bream; c) species with omnivorous feeding habits and a broad trophic niche in which both planktonic and benthic food categories were consumed. In winter, barbel and mirror carp were clustered into this group. In spring, the common carp also appeared in this group, and in summer it was associated with roach and white bream. Results from detrended analysis located these three trophic groups in a three-dimensional space defined by the three first components axis from the analysis (Fig. 7). DC I was a general bottom-foraging-habitat-related, DC II was mainly defined by the consumption of cladocerans and ephipids, and DC III by the consumption of macroinvertebrates (Table 4). These three components were able to absorb the 73.7% of the data variance