Enables alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase activity. Involved in oligosaccharide biosynthetic process. Acts upstream of or within ganglioside biosynthetic process. Located in cytoplasm. Is expressed in alimentary system; axial muscle; brain; and craniocervical region bone. Orthologous to human ST6GALNAC6 (ST6 N-acetylgalactosaminide alpha-2,6-sialyltransferase 6). [provided by Alliance of Genome Resources, Apr 2022]