Spring is in the air and the Great Barrier Reef is about to explode with new life. Divers descend into dark water in the hope of seeing the world’s biggest simultaneous orgasm during the annual coral spawn. Manta rays drop in like great alien space ships to filter-feed on the nutrient rich waters. Thousands of sea birds congregate on the islands and coral cays to nest, while in the mangroves saltwater crocodiles violently defend their eggs. In the far North, rangers and scientists fight to control a potentially catastrophic plague of coral-eating crown of thorn starfish.