Improving feeding of Tigriopus japonicus under various stocking densities on Tetraselmis suecica as a potential live feed for fish larvae

Feeding rates of adult copepods is an important parameter that determines their productivity and population growth. Feeding is influenced by several factors including food quantity and copepod density. The marine harpacticoid copepod, Tigriopus japonicus , is used in the testing of contaminants in marine ecosystems and is also a promising candidate for mass cultivation. However, information on its feeding responses under different stocking densities and feed supplies are lacking. Therefore, this study investigated the effect of copepod densities and microalgal feed concentrations on the ingestion and clearance rates of Tigriopus japonicus on the marine chlorophyte Tetraselmis suecica . The saturation point of feeding for T. japonicus was 486.48 µg C L ^− 1 and the maximum ingestion rate was 3.84 µg C ind ^− 1 d ^− 1 at 40 ind. L ^− 1 . At the same microalgal feed concentration, ingestion rates decreased at copepod densities > 800 ind. L ^− 1 . The ingestion rates significantly increased when microalgal feed concentration was increased up to 15,000 µg C L ^− 1 at copepod densities > 800 ind. L ^− 1 despite no changes in the clearance rates. Increasing feed allocation increased the ingestion rates with similar levels reached for 40 ind. L ^− 1 and 200 ind. L ^− 1 . The findings of the study indicate that decreased feeding in high density conditions may be overcome by providing more food to T. japonicus .