The major threats are from coastal development, destructive fishing practices, overexploitation of marine resources, marine pollution and sedimentation from inland deforestation and farming.

CNN: Task force announces coral reef protections

Dr Worm and his colleagues discovered that the more species an ocean region has, the more robustly it seems to cope with overexploitation.

ECONOMIST: Marine biodiversity

"Sharks are very vulnerable to overexploitation, and the consequences of depleting their numbers may have very serious consequences not only for sharks but also for marine ecosystems and for fishermen themselves, " he said.

BBC: EU gives shark protection teeth

Problems arise from conflicts between different uses of coastal land and waters, overexploitation of coastal resources, discharge of wastes and effluents into coastal waters, increasing stress by sea level change and growth of coastal population.

UNESCO: Water Portal | Water Events Worldwide

Unless action is taken now, the consequences of our activities are at a high risk of causing, through the combined effects of climate change, overexploitation, pollution and habitat loss, the next globally significant extinction event in the ocean.

FORBES: A Call to Arms on Climate Change