The North Pacific coast is a landform of islands, metaphorically called the necklace of the earth, through which cold currents flow in a counterclockwise direction. The North Pacific coast is home to a variety of speciation mechanisms that result from geological history and topography, including habitat fragmentation due to sea-level change, the opening of straits to the marginal seas, and environmental gradients based on latitude and depth. Large-scale phylogenetic and gene expression analyses will elucidate the origin and evolutionary processes of North Pacific Rim marine biology.