Simulation of larval dispersal between seamounts for regional environmental management plans of deep-sea mining

In deep-sea mining, understanding genetic connectivity through larval dispersal can be the basis for regional environmental management plans. This study conducted larval dispersal simulations for seamounts in the Northwest Pacific where potential mineral resources, cobalt-rich crusts, are distributed. A total of 19 seamounts were selected for simulation within a 1000 x 1000 km2 area around seamounts where contracted areas for exploration of cobalt-rich crusts were established by the International Seabed Authority. The pelagic larval duration was assumed to be 97 days, which is the average for deep-sea species (Hilário et al., 2015, Front. Mar. Sci.). Two-dimensional dispersions were calculated at a depth of 900 m just above the seamount summits. Flow velocity data were obtained from the ocean model JCOPE2M. The simulation results showed that seamounts with contracted areas for exploration were divided into separate clusters in the larval dispersal network. Seamounts without contracted areas served as sources or sinks of larvae to seamounts with contracted areas. These results may provide fundamental insights for effective environmental management based on interactions among seamount populations.