[Bioremediation potential of Apostichopus japonicus (Selenka) in coastal bivalve suspension aquaculture system].

Suspension aquaculture of filter-feeding bivalves can produce large amount of faeces and pseudofaeces (biodeposits) that may impact aquaculture environment, while deposit-feeding sea cucumbers may effectively utilize such particulate wastes and act as a scavenger in mariculture system. In this paper, the ingestion, growth, and excretion of deposit-feeder Apostichopus japonicus were investigated in situ seasonally to evaluate its bioremediation potential of a suspension aquaculture system of filter-feeding bivalves. The results showed that A. japonicus could grow well in newly designed culture nets, with its maximum specific growth rate being 0.34% d(-1). The A. japonicus could effectively use the biodeposits generated by co-cultured bivalves, and the ingestion rate at 21.2 degrees C in summer, 19.2 degrees C in autumn, and 7.7 degrees C in winter was 0.1746, 0.0989, and 0.0050 g g(-1) d(-1), respectively. A. japonicus could promote the regeneration of nutriens in biodeposits via the excretion of considerable amount of dissolved N and P, and the excretion also showed obvious seasonal fluctuation. The extrapolation based on the in situ investigation results showed that when co-cultivated with bivalves in lantern nets, A. japonicus would ingest 4.5-159.6 kg hm(-2) d(-1) of dry biodeposits and excrete 1,382.5-3,678.1 mmol hm(-2) d(-1) of NH4(+)-N and 74.6-335.7 mmol hm(-2) d(-1) of PO4(3-)-P, indicating that the deposit-feeding A. japonicus had a great bioremediation capability in suspension aquaculture systems. The integrated model of deposit-feeding A. japonicus and filter-feeding bivalve could not only benefit the economy, but also sustain the environment.