Quantification of particulate size class ingestion, egestion, and water clearance rates by the orange-footed sea cucumber, Cucumaria frondosa, and implications for Integrated Multi-Trophic Aquaculture (IMTA)

Abstract

The sea cucumber Cucumaria frondosa is a candidate for Integrated Multi-Trophic Aquaculture (IMTA) farms as a species to extract organic effluent. Ingestion, egestion, and water clearance rates, and size of particulates ingested were assessed for C. frondosa, through field and laboratory experiments. Sea cucumbers in the field had a clearance rate of 7.2 L∙individual[superscript -1]∙day[superscript -1], significantly different from those feeding in the laboratory (3.6 L∙individual[superscript -1]∙day[superscript -1]). Ingestion rates of C. frondosa feeding in the field (38 mg∙individual[superscript -1]∙day[superscript -1], SD=18) and in the laboratory (30 mg∙individual[superscript -1]∙day[superscript -1]) were not significantly different. Nor were egestion rates in the field (13 mg∙individual[superscript -1]∙day[superscript -1]) or laboratory (11 mg∙individual[superscript -1]∙day[superscript -1]). There was little reduction in particulate concentrations in laboratory experiments, making it unclear which sizes of particulates sea cucumbers are primarily ingesting, C. frondosa is unlikely to remove large quantities of waste effluent from IMTA farms, although it will likely remain a potential candidate due to its marketability and ability to efficiently absorb waste.