The lower part of the Orange River forms the border between Namibia and South Africa from the mouth of the river and 580 km upstream. The river origins in the Lesotho Highlands, and runs for approximately 2300 km from the source to the Orange River Mouth at Oranjemund (Namibia) and Alexander Bay (South Africa), where it discharges into the Atlantic Ocean. The total Orange River catchment is approximately 1000000 km². The fish diversity in the Lower Orange River is relatively low. Keywords: Lower Orange River, Namibia, fish populations, management of fisheries, Ramsar site.