Analysis of the impact of Holoth aria scabra intensive farming on sediment

摘要

We analysed the impact of intensive Holothuria scabra farming by comparing various parameters of the sea cucumber food (i.e. the upper layer of the sediment) inside and outside the pens of two farms in the south-west of Madagascar. Our analyses showed that: (i) the proportion of the finest grain size fraction (<250 jim) decreased from 5 to 14%, (ii) the global carbonate proportion decreased by 5%, (iii) aragonite was the carbonate type most affected by holothurians, followed by calcite and magnesian calcite, (iv) the total organic matter did not vary significantly, (v) the number of bacteria decreased by up to 50%, and (vi) the concentration of photosynthetic microorganisms fell by up to 22%, within sea farm pens. Based on these results we suggest that fallow practice should be considered in the future for holothuriculture.