Many varieties of fish are taken opportunistically and randomly, as opposed to pike and bream, which can locally appear to be selected out of proportion to their regional population. Particularly diverse in the white-tailed eagle's prey spectrum are the family Cyprinidae, of which more than 20 species are known to be predated including the common bream. Others taken with some preference may include salmonids and cod and their allies, both families known to obtain relatively large body sizes and occasional habituate shallow water, as well as lumpsuckers, because they are benthic. In Greenland, the leading prey species is the salmonid, the Arctic char ("Salvelinus alpinus"), which comprised 27.2% of 660 prey items. The secondary prey in Greenland was recorded as two species of cod. While the Arctic char can average up to and cod can sometimes grow considerably larger than that, the average weight of cod taken here was estimated at only and the average char at . In Norway, of 524 fish prey items, the common lumpsucker ("Cyclopterus lumpus"), which averages up to but is usually smaller, made up 24% of fish taken and the Atlantic wolffish ("Anarhichas lupus") made up 17% of fish taken. However, fish were secondary to birds overall in Norway. Per two studies from Sweden, fish were usually the main food unlike in Norway and Finland and could comprise from 51-60% of the diet. Fish were also somewhat dominant in the foods from two studies in Belarus, making up 48.1-53.7% of the diet. Fish similarly were important to nesting eagles in Hokkaido, where 54% of 533 prey items were fish, led by the Alaska pollock ("Gadus chalcogrammus") at 18.4%. In different studies of the Danube Delta of Romania, from 44.6% to 79% of the diet was comprised by fish, led by the common carp ("Cyprinus carpio") and Prussian carp ("Carassius gibelio"). In the Kostomuksha Nature Reserve of Russia, fish were strongly dominant in food remains, making 80% of the known diet.