In a descriptive study of megafauna of several Southeast Atlantic seamounts, multiple video-transects on upper slopes and summits documented the occurrence of benthic invertebrate taxa, primarily corals, regarded as indicators of vulnerable marine ecosystems (VMEs) as defined in international guidelines. At Schmitt-Ott Seamount there was a pronounced dominance of gorgonian corals (seafans, Alcyonacea). In all other study areas the diversity was greater, and more scleractinians (stony corals, Scleractinia) were observed. Scleractinian corals were mainly dead, and much of the coral framework and rubble may have been ancient. In the Valdivia complex and on Ewing Seamount, which are open to fisheries, scleractinians seemed restricted to some slopes of knolls, and on Valdivia Bank and the subarea denoted Valdivia West the summit substrate was mostly bare rock. Pelagic armourhead Pseudopentaceros richardsoni and splendid alfonsino Beryx splendens (two targets of commercial fisheries in the area) were observed at a few sites, but did not appear to be abundant in the main former fishing areas of the Valdivia area. Orange roughy Hoplostethus atlanticus was common in video records around the summit at Ewing Seamount. The deep-sea red crab Chaceon erytheiae was abundant in the Valdivia area and at Ewing Seamount, and crabs were distributed across a more extensive depth range than the fishes. In areas with high densities of live coral, the video records suggested that the benthic communities were intact and not impacted by fishing. Evidence of past fishing activities included observations of lost pots and rope at Vema Seamount and in the Valdivia area.

Most of the Southeast Atlantic Ocean is abyssal, and global bathymetries suggest that only similar to 3.2% of the areas beyond national jurisdiction (ABNJ; also known as the high seas, as defined in the United Nations Convention on the Law of the Sea [UNCLOS]) are shallower than 2 500 m. This study mapped bathymetry and characterised substrates in selected seamount summit areas, including several that have been or may become fishing areas. The southernmost location, the Schmitt-Ott Seamount, has exposed volcanic bedrock with surrounding flats covered by thin biogenic sediments and/or coral rubble that appears ancient. At Wust, Vema, Valdivia and Ewing seamounts the basaltic base appears to be overlain by coral caps and other coral substrates (sheets, rubble). Adjacent summit plains have biogenic sediments of varying thickness. Vema has a flat, roughly circular summit, <100 m deep, with the shallowest point being a 22-m-deep summit knoll; the upper slopes have ancient coral framework, but the summit has a mixture of coralline and volcanic rock and coarse sediments, including extensive areas with coralline algae and kelp forests. Valdivia Bank is a 230-m-deep, flat, rocky area (similar to 11 x 5 km), protruding steeply from the extensive multi-summit Valdivia subarea of the Walvis Ridge. The distribution of past fisheries in the Convention Area of the South East Atlantic Fisheries Organisation (SEAFO) was considered in relation to the new information on bathymetry and substrate.

The South African hake resource consists of two species: the shallow-water Cape hake Merluccius capensis and the deep-water hake Merluccius paradoxus. It is the largest and commercially most important component of the catch of all four fishery sectors that target hake, as well as of South African fisheries overall. Collectively, it provides the basis for some 30,000 jobs and a landed value of more than US$ 225 million. Aspects of the biology and ecology of the two species are described, including their distribution, life history strategy, reproduction, growth and feeding. The history of the fishery is discussed with special reference to management interventions. A relatively conservative management strategy was implemented after the declaration of the South African Exclusive Fishing Zone (EFZ) in 1977 in order to rebuild following over-exploitation of the resource during the 1960s. Since 1977, the primary regulatory mechanism has been an annual total allowable catch (TAC). Prior to 1991, the TACs were proposed on the basis of annual assessments. Thereafter, an Operational Management Procedure approach was used. Recent annual catches have remained relatively stable in the range of 120,000–150,000 t. Certification of the South African hake trawl fishery by the Marine Stewardship Council in April 2004, followed by re-certification in March 2010, has been a strong driver of taking ecosystem considerations into account in the management of the resource.