Scientists have explored less than one per cent of the deep sea. We know neither the extent of the habitats targeted by mining nor how the ecosystems will respond to it. Most of the species that live on the seafloor remain unknown to science, as do their lifestyles, interactions and ecological roles. Developing strategies to protect them is a major challenge. We do know that many deep-sea species are particularly vulnerable to the destruction of habitat by deep-sea mining. They grow slowly, live for decades or even centuries and reproduce late in life.