Evaluating the feasibility of integrated multi-trophic aquaculture (IMTA) for the sea cucumber Holothuria sanctori with finfish and shellfish

Deposit-feeding sea cucumbers are highly potential extractive species within Integrated Multi-Trophic Aqua- culture (IMTA) systems. This study investigated the feasibility of the sea cucumber Holothuria sanctori in pilot- scale IMTA systems with finfish and shellfish over a six-month experimental period. The experiment assessed the survival, growth, and bioremediation potential of H. sanctori (mean weight: 77.74 +/- 32.23 g) using two bottom-placed rearing systems (cages and sediment traps) under finfish and mussel aquaculture waste conditions. In the IMTA system with finfish, H. sanctori performed optimally in the cage model, achieving a survival rate of 96 %, and a specific growth rate of 0.10 +/- 0.05 % per day. In the IMTA system with mussels, the sea cucumber's optimal performance was observed in the sediment traps, with a 100 % survival rate, and a specific growth rate of 0.21 +/- 0.08 % per day. Additionally, the bioremediation capacity of H. sanctori was assessed through a comparative analysis of organic matter (OM) content in sediment traps with and without sea cucumbers. Results indicated a reduction in organic content in sediment traps containing H. sanctori, compared to those without sea cucumbers. This study is the first to evaluate H. sanctori co-cultivation with finfish and mussels in IMTA systems, demonstrating its high potential as an extractive species.