Abstract
The Great Cormorant Phalacrocorax carbo is generally considered to be a major predator of Sweetfish Plecoglossus altivelis released primarily for recreational fishing. We counted Great Cormorants, herons and anglers along 400 km of rivers and at seven lakes in or close to Tochigi Prefecture at the end of May, June and August 2005. We recorded a total of 433 Great Cormorants, 516 herons of four species, and 736 anglers. Along rivers suitable for Sweetfish angling, Great Cormorants were fewer than at other sites and fewer than Grey Herons Ardea cinerea, Great Egrets Egretta alba, or anglers.
