 This occurred during the last glacial maximum (18,000 BP) when the basin was completely isolated.Sea level rise during the marine transgression flooded the basin, forming a marine embayment from 11,800 BP to 8700 BP and the basin rim was completely flooded by about 8000 BP, at which point Bass Strait was formed and Tasmania became a separate island.Like the rest of the waters surrounding Tasmania, and particularly because of its limited depth, it is notoriously rough, with many ships lost there during the 19th century.