Smooth fan lobster Ibacus novemdentatus in the southwestern Indian Ocean: an overlooked fisheries resource?

Abstract

Bottom-trawl data collected by the RV Dr Fridtjof Nansen off Mozambique (in 1990, 2007 and 2018) and off eastern South Africa (in 2018) were analysed to investigate the distribution, abundance and size composition of the smooth fan lobster Ibacus novemdentatus as a potential fisheries resource. The lobsters occurred shallower (depth 53–297 m) than traditional deep-water trawl grounds, were concentrated in ‘hotspots’ at the seaward edges of sand/mud banks at the Thukela Bank, Delagoa Bight and Sofala Bank, and exhibited segregated juvenile and adult populations. Three other high-value lobster species and several marketable teleost species occurred in trawl nets where I. novemdentatus was present. Further exploration by trawling should be considered to better define hotspots of adults of this species and to investigate the contribution that I. novemdentatus could make to mixed-species commercial catches.

Keywords: crustaceans, deep-water trawls, EAF-Nansen Programme, fisheries development, mixed-species catches, survey data