English explorers were Francis Drake in the sixteenth century and Captain James Cook in the eighteenth century. The latest developments in deep sea exploration have revealed a world of creatures living at depths which were thought to make life impossible. For example the Pogonophora worms inhabit the seabed near vents or cracks in the sea floor where water comes into contact with the molten earth. The Pacific Ocean ecology is under threat from a variety of directions. The Great Barrier Reef and other corals are being steadily eroded by the spread of the crown of thorns starfish which eats away at coral.
Coral is also at risk through pollution and the effects of tourism.
Many of the area's species, such as sea turtles and sea lions are under special threat. The sea otter came close to extinction early this century from overhunting. Similar pressures on the whale population have only recently been eased by the ban on whaling. Many of the islands of the Pacific have been damaged by the introduction of non-native animal species, such as pigs in Hawaii. The pressure of tourism on the fragile ecology of reefs and islands is a new danger resulting from the growth of modern air travel.