An observation of Calanus marshallae Frost, 1974, on the Atlantic side
of the Polar Ocean is reported. Copepods were identified by comparing
nucleotide sequences of mitochondrial 16S ribosomal RNA with a previo
usly reported sequence from the Pacific region. Presence of the specie
s in the Barents Sea may explain multi-modal length distributions prev
iously obtained in the region. Potential implications for future ident
ification of Calanus spp, in this region are discussed.