Anatomy and physiology

Morphology - shape of arctic charr

Charr is a streamlined fish with a relatively small head. It is thickest around the belly and narrows smoothly towards the head and the strong tail. Its shape can be variable between breeds, this is especially true for the shape and size of the head and the ratio between length and thickness of the fish. The head extends to right behind the operculum, where the trunk starts. The tail starts right behind the anal opening. The head is smooth and without scales. The pectoral fins start right behind the operculum. The pelvic fins are ventrally at the midlength of the fish and the anal fin is right behind the anus. The dorsal fin is dorsally at the midlength of the fish and the tail fin or caudal fin is placed symmetrically on its tail. Its second dorsal fin, the adipose fin, is the distinguishing feature of the genus salmonidae.

Figure: Morphology of Arctic charr