Enables sialyltransferase activity. Involved in several processes, including neuron projection extension; positive regulation of synapse assembly; and response to cocaine. Located in perinuclear region of cytoplasm and plasma membrane. Orthologous to human ST8SIA2 (ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 2). [provided by Alliance of Genome Resources, Apr 2022]