Spatial management of deep-sea seamount fisheries: balancing sustainable exploitation and habitat conservation

Seamounts throughout the world's oceans can support diverse and abundant fish communities. Many have been subject to commercial deep-sea bottom trawl fisheries and have exhibited ‘boom and bust’ characteristics. There is growing concern about the effect of fishing on fragile and vulnerable benthic invertebrate species. This review examines why deep-sea fisheries have generally failed, and recommends measures that are necessary to improve their sustainability. Much is based on lessons learned in the south-west Pacific that may be more generally applicable to global deep-sea fisheries. Sustainable fisheries require highly precautionary feature-based catch limits, and credible and timely stock assessment advice. Management also needs to consider fishing impacts on the benthic habitat, and while reducing and spreading fishing effort on seamounts is beneficial for fish stocks, it can have a negative effect on the benthos. To balance exploitation and conservation, elements of spatial management are required, whereby some seamounts are protected before any fishing has occurred. Protected areas should include entire seamounts, and multiple seamounts in a network. A management regime should incorporate closed seamounts, open seamounts for fishing, and management of adjacent slope areas where these are important for the productivity of fish and invertebrate populations.