Rockhopper penguin positions and islands became surrounded by subtropical water masses, resulting in a split between Northern and Southern rockhopper penguins. Many advance and retreat cycles of Patagonian icecaps during the late Pleistocene may have created a barrier to gene flow between Southern Pacific and Southern Atlantic populations, causing a split between Southern and Eastern rockhopper populations. Adult Rockhopper penguins have no land-based predators. They are eaten when at sea by leopard seals, fur seals, killer whales and blue sharks. Chicks and eggs are eaten by many birds including giant petrels, skuas, sheathbills and various types of gulls. Although the rockhopper penguin
Rockhopper Exploration in production licences PL023, PL024, PL032 and PL033 covering approximately 3800 km. In 2005 it farmed into licences PL003 and PL004 operated by Desire Petroleum plc. In 2011, Rockhopper increased its share of PL004b from 7.5% to 60.0% and in PL004c from 7.5% to 25.0%. Licence PL004b contains an extension to the Sea Lion field as well as the Beverley, Casper and Casper South discoveries. The Rockhopper board comprises eight directors; a non-executive chairman, three executive directors and four non-executive directors, one of whom acts as senior independent director. Four of the non-executive directors are considered to be independent. The