Introgressive hybridization between the Atlantic and Pacific herrings (Clupea harengus and C. pallasii) in the north of Europe.
We present evidence of mitochondrial and nuclear introgression from the Atlantic herring Clupea harengus into the Pacific herring C. pallasii in northern European seas, where the two species have come into secondary contact following the post-glacial trans-Arctic invasion of Pacific herring to the Atlantic realm. Although the breeding areas of the two species are thought to be separate, 7 % of the