Eastern rockhopper penguin genetic divergence with the southern rockhopper penguin may have been caused by a vicariant event caused by a shift in the position of the Subtropical Front during the mid-Pleistocene climate transition. Analysis of a part of a mitochondrial control region from a northern rockhopper penguin found on the Kerguelen Islands showed that it may have come from Gough Island, 6,000 km away, and that the southern and northern rockhoppers are genetically separate, though some individuals may disperse from their breeding colonies. Many taxonomists have yet to recognize the split, although some are beginning to do so. "E. c. filholi" breeds
Rockhopper Exploration viable rates. In July 2012, Rockhopper announced that it had entered into a conditional farm out agreement with Premier Oil plc whereby Premier will acquire 60% of Rockhopper's interests in its North Falkland Basin licences in exchange for an upfront cash payment of $231m, a contribution of $722m to Rockhopper's share of the Sea Lion development costs and a net exploration carry of $48m. Rockhopper will be fully funded on its share of the Sea Lion development through the contribution to costs and standby financing provided by Premier. First oil from Sea Lion is expected in 2020. Rockhopper holds interests