A broad overview of Namibia's marine resources and commercial fisheries is presented. Five primary impacts of the proposed Sandpiper phosphate mining are suggested. These are: the likely impact of mining on commercial fisheries; the likely impact of mining on the main commercial fish species; the likely impact of mining on the recruitment of commercially important species; the likely impact of mining on fish biodiversity and the likely impact of mining on seabirds and marine mammals. We conclude that the impact on Namibian fisheries will vary depending on the sector. Overall the significance of impact on the fishery sector is considered to be negative and of medium to low significance. Of the main commercial fisheries, the monk-directed trawl fishery will be most impacted. The dredging will potentially cover a significant portion of the historical monk trawling grounds (13.8 % of the Mining Licence Area) with a displacement and mortality of the resource in the target mining sites.