The sea cucumber stocks off the east and northwest coasts of Sri Lanka were estimated by
surveying 1307 km2 and 1779 km2 by an underwater visual census (UVC)
in June and October 2008 respectively. The presence of twenty-five sea cucumber species
belonging to seven genera; Actinopyga, Bohadschia, Holothuria, Pearsonothuria,
Stichopus, Thelenota and Acaudina was identified in five
hundred sampling sites randomly selected in each area. The overall average density (± SD) of sea cucumbers was higher in the northwest (350 ± 648 ind ha-1) than in
the east (90 ± 130 ind ha-1) and low-value species were predominant in both
survey areas (79 ± 125 ind ha-1 in the east, 244 ± 488 in the northwest) when
compared with medium (10 ± 34 ind ha-1, 105 ± 175 ind ha-1,
respectively) and high-value category (<2 ind ha-1).
The estimated total biomass in the northwest (13 024 t) was roughly four times greater
than the east (3027 t). Holothuria edulis was the most abundant species
in numbers while Holothuria atra had the highest stock biomass in both
areas. Sea cucumber densities were significantly different among the habitat
(p < 0.001) and depth categories. The highest
density was reported in rocky habitat associated with seagrass and / or macroalgae. The
density of low-value species was significantly high in 1–10 m depth category
(p < 0.001) in the northwest while other
commercial groups were dominant in 20–30 m depth range in both areas. Temporal banning of
the fishery for high and medium-value species would be a better management option to avoid
further stock depletion.