The Lower Congo region is the section of the Congo River from the outlet of Malebo Pool at Kinshasa to the coast. It occupies 2% of the Congo Basin but contains nearly 30% of the basin's fish species (Research Outreach, 2019), and ca. 30% are endemic (Brooks et al., 2011). They are highly adapted to the turbid, fast-flowing waters of the rapids, which drive high levels of speciation (Research Outreach, 2019). The Lower Congo is the second-highest center of threatened freshwater species in Central Africa (Brooks et al., 2011). It is a freshwater biodiversity hotspot, in terms of species richness, endemism, and threats. The Congo River is one of a few, long, substantially free-flowing rivers left in the world (Grill et al., 2019). An analysis of the IUCN Red List shows that there are more than 1,200 freshwater species present in the Lower Congo that have been assessed by IUCN. One can expect that there are many more undescribed. Altering the hydrological and sediment flow regime of the Congo River will have significant negative impacts on its highly diverse and endemic biodiversity. Unfortunately, the Lower Congo is also a target for hydropower development, with proposals for development of the Grand Inga dams project, which would divert 83% of the Congo River’s average flow, raise water levels as far as 180 km upstream, create a reservoir of about 40 km2, and permanently displace ca. 6,300 people (International Rivers, 2014). The river’s large sediment load also creates the Congo Plume, a plankton-rich fan water extending 300,000 km2 into the Atlantic Ocean. It is a carbon sink of global importance, which could collapse if the sediment flow which sustains it is interrupted (Showers, 2009).

Sources:

Research Outreach (2019). https://researchoutreach.org/articles/fishes-lower-congo-river-extreme-case-species-divergence-convergent-evolution/

Brooks et al. (2011). https://www.iucn.org/content/status-and-distribution-freshwater-biodiversity-central-africa-0 Grill et al. (2019). https://www.nature.com/articles/s41586-019-1111-9 7

International Rivers (2014). https://archive.internationalrivers.org/resources/congo-river-death-by-a-thousand-cuts-8222