Seamounts are isolated topographic elevations with summit depths at least 100 m above the seafloor. Recent estimates of the number of seamounts have ranged from 171,864 seamounts and to more than 25 million seamounts with a relief of more than 100 m in height. Those with a relief of > 1000 m cover an estimated 4.7% of the ocean floor while features < 1000 m in elevation cover 16.3% of the seafloor, which is equivalent to or greater than the area covered by tropical dry forestsor by temperate broad-leafed forest or grassland. They are hotspots of biological diversity, and one of the main forms of impact have come from deep-sea fisheries, including bottom trawling. Other and future impacts come from deep-sea mineral mining. Management of these areas and implementation of sustainable fisheries has been problematic, but there has been some modest progress in limiting damage to seamount ecosystems, but to date this is inadequate.