Occurrence of Acanthocephalus minor (Acanthocephala) in two types [Freshwater and middle-reach types] of the goby, Chaenogobius annularis [collected from Ryukei river, Hokkaido, Japan]

acanthocephala agentes nocivos alimentos anatomia anatomia animal anatomie anatomie animale anatomy animal animal anatomy animal aquatique animal nuisible animales animales nocivos animals appareil digestif aquatic animals aquatic organisms asia asie biological competition biological properties body parts bony fishes digestive system facteur nuisible fishes foods helminthe helminths helmintos injurious factors inland waterways intestin intestines intestinos invertebrados invertebrates japan japon noxious animals organisme aquatique organisme nuisible parasite parasites parasitism parasitisme parasitismo partes del cuerpo partie du corps peces pests physiographic features plagas poisson osseux produit alimentaire rivers sistema digestivo transport transporte vertebrados vertebrates vertebre