In Alaska, development interests are pitted against conservationists on the question of whether the coastal plain of the Arctic National Wildlife Refuge shall be opened to oil exploration. The area in question lies close to Prudhoe Bay's enormous reserves of petroleum and natural gas. It is also the primary calving ground for the Porcupine caribou herd of some 180,000 animals, and the public debate centres on how this herd, that migrates between Alaska and Canada, would be affected. The decision on opening the Arctic coastal plain to development will rest with the US Congress.