The most frequently recorded prey species in 18 food studies from across the range is the northern pike ("Esox lucius"), present in at least 16 of those studies. Pike were found to be the main prey species in both the Baltic Sea and Lapland in Sweden, at three breeding locations in Finland, in two studies from Germany and in Belarus. The maximum representation of pike known was in Lapland, Sweden where they comprised 38.2% of 809 food items. Considered a top predator in many freshwater ecosystems (and thus with less significant anti-predator camouflage), the pike may be more conspicuous than many fish to hunting eagles due to the fish's boldly speckled flanks. While an average mature weight for a pike is around , white-tailed eagles often attack larger sized pike, with an estimated average weight range of . Some pike taken by white-tailed eagles were even estimated to weigh around , however the eagle would be unable to fly with such a large catch and would need to row it to the nearest shore. The next most widely reported fish prey species is the common bream ("Abramis brama"). This bream was reported in 10 of 18 dietary studies and was the main prey in the Polesie State Radioecological Reserve, Belarus, in the Ural mountains region of Russia, and in the Kostomuksha Nature Reserve, Russia. Like the pike, the relatively large size of common bream, which weigh about on average, can prove attractive to hunting eagles. They are also vulnerable to tapeworms so can be easily taken while floating close the water's surface in ill condition.