An assessment of holothurian diversity, abundance and distribution in the shallow lagoons of Mauritius

The sea cucumber industry, which is known to be particularly vulnerable to overexploitation and collapse, has been under tremendous pressure in Mauritius since the mid-2000s. Consequently, in 2010, the Ministry of Fisheries imposed a two-year ban on the collection of sea cucumbers, which was later extended for another four years (2012–2016) to avoid the collapse of the fishery. This study collected data on the diversity and abundance of sea cucumbers in the shallow lagoons of Mauritius in order to assist with the sustainable management of the fishery. Previous surveys conducted in 2011 in the lagoons of the south and west coasts of the island revealed the presence of 17 holothurian species. The present study visited some of the earlier study sites as well as some new ones in the north and east coasts to assess sea cucumber abundance and diversity. From March to June 2013, 115 daytime transects at 23 sites (totally 92,000 m² in area) revealed a total of 7,488 holothurians, of which 76% were of commercial importance. The holothurians were distributed within a range of habitats with no significant correlation detected between abundance and habitat types. Holothurian distribution in the shallow lagoons of Mauritius seems to be influenced by physical, biological and anthropogenic factors. The present survey revealed that some species could be recovering from exploitation.