 Once the coastlines of Alaska and British Columbia had deglaciated about 16,000 years ago, these kelp forest (along with estuarine, mangrove, and coral reef) habitats would have provided an ecologically homogenous migration corridor, entirely at sea level, and essentially unobstructed.A 2016 DNA analysis of plants and animals suggest a coastal route was feasible.Mitochondrial subhaplogroup D4h3a, a rare subclade of D4h3 occurring along the west coast of the Americas, has been identified as a clade associated with coastal migration.