The Effects of Hypoxia and Anthropogenic Disturbance on the Distribution, Abundance and Recruitment of the Sea Cucumber Holothuria leucospilota at the Mouth of a Subtropical Bay, China

Despite the commercial importance of sea cucumber Holothuria leucospilota increasing in recent years, little is known its spatial distribution and ecology South China Sea. We investigate distribution, abundance, recruitment H. from 2017 to 2020 at two sites (S1 S2) Daya Bay, a typical subtropical bay which strongly influenced by human activities report hypoxia drive deeper into shallower waters with higher DO concentrations mouth Dapeng Cove Bay (S1), particularly during summer. Population size S1 decreased 90% levels, before this area was opened public 2018; not observed August (summer) 2020. In contrast, summers 2020, abundance S2, protected open-water area, increased 84%, proportion small-sized (recently recruited) population 20%. Severe summer could negatively influence spawning larval settlement, combined depletion broodstock because fishing pressure and/or hypoxia-induced mortality, inhibit recruitment. abundant (the breeding season) favoured S2. Overall, anthropogenic disturbance impede recovery S1, while larvae may be released settle nearby areas. It imperative develop better understanding biology, conservation tropical cucumbers China.