Life on our blue planet depends on healthy oceans, but recent reports warn that sea life faces the next mass extinction. Next to climate change, overfishing is the single greatest threat to marine biodiversity. Industrial fishing has reduced populations of large, predatory fish like tuna, cod and sharks by about ninety per cent in the last fifty years. Growing demand for seafood, wasteful fishing practices and mismanaged fish stocks and aquaculture operations are leading to broken links in marine food chains in Canadian waters and worldwide. Urgent action is needed to protect marine life and allow recovery. Greenpeace works to relieve pressure on ocean ecosystems and to establish a network of no-take marine reserves–ocean parks–covering 40 per cent of the world's oceans.