Distribution of Bathynectes piperitus (Brachyura: Portunidae) in the Benguela Upwelling Region and Its Relationship with Some Environmental Parameters

Distribution and abundance patterns in relation to some environmental parameters and population size structure have been studied in the deep-water portunid crab Bathynectes piperitus in the Benguela upwelling region. The highest densities were found between 300 and 400 m depth, especially between latitudes 24°S and 28°S, associated with oxygen levels higher than 0.51 ml/l, and bottom temperatures of 7-8°C. Sediment granulometry did not appear to play a crucial role in determining the distribution pattern of the species; high abundances of B. piperitus occurred on sediments with 20-80\% silt-clay content. Sex ratio was highly male-biased at both depth extremes of the distribution. The main recruitment area was found between 200 and 300 m in latitudes 23°S and 24°S. No single environmental parameter appears to be responsible for the species' main distribution patterns in this area.