Analyzing the potential of the sea cucumber parastichopus regalis for bioremediation of aquaculture wastes

30th New European Society for Comparative Physiology and Biochemistry (ESCPB) Congress, Unraveling complexity: from molecules to ecosystems, 4-7 September 2016, Barcelona.-- 1 pageAquaculture enhances food availability and provides economic and social benefits to coastal communities but there are concerns about the ability of the environment to sustain aquaculture expansion. Farming operations release particulate organic matter (unconsumed feed and fish feces) and inorganic nutrient excretions. The organic wastes settle onto the seabed and produce enriched sediments, which organic matter can be potentially consumed by bottom feeders. In recent years, integrated multi-trophic aquaculture (IMTA) has been proposed as a sustainable approach to mitigate the ecological effects of monoculture systems. Several studies have demonstrated the functional role of sea cucumbers such as Apostichopus japonicus, Australostichopus mollis and Parastichopus californicus to ameliorate the adverse effects of organic matter enrichment in coastal ecosystems. Parastichopus regalis is a holoturian of the family Stichopodidae which five muscle strips have high commercial value in the Spanish Mediterranean Sea. In a recent project (ref. AGL2011-25382) we have studied several aspects of its biology (feeding, reproduction, habitat requirements and behavior). Experimental estimation of feeding parameters (gut transit time, feeding rate and food assimilation efficiency) was performed. The main results obtained showed that P. regalis exhibited a positive selectivity for organic particles. The organic matter assimilation efficiency of the digestive tract was 26%. The estimated gut residence time ranged between 4 and 15 hours. Feeding rate estimates ranged between 0.01 and 1.78 g h-1. In light of these results, the sediment processing rate of P. regalis will be compared with published data on other sea cucumbers to evaluate if this species is an elective candidate for bioremediation in Mediterranean aquaculture farmsPeer Reviewe