Sea lamprey found in the northern and western Atlantic Ocean along the shores of Europe and North America, in the western Mediterranean Sea, the Black Sea, and in the shores of the Great Lakes. They have been found at depths to 4000 m and tolerate temperatures between 1.0 and 20 °C. The largest European populations of sea lampreys are located throughout the south-western areas of Europe (north-central Portugal, north-northwest of Spain, and west–south-west of France). These countries also support the main fisheries of the species. Sea lampreys are anadromous. From their lake or sea habitats, they migrate up rivers to spawn (followed
African admixture in Europe Europe may have a common origin in Asia (e.g. Y haplogroups R1, and some paternal haplogroup T and U subclades). One subclade of haplogroup U, namely U6a1, is known to have expanded from northern and eastern Africa back into Europe even though haplogroup U6 is considered to have originated in the Middle East. Other lineages are known to have moved from Europe directly into Africa, for example mitochondrial haplogroups H1 and H3. Such bidirectional migrations between Africa and Eurasia complicate the task of defining admixture. One proposed example of Holocene gene flow from Africa to Europe, via the Middle East,