Feeding response of the dendrochirote sea cucumber Cucumaria frondosa (Echinodermata: Holothuroidea) to changing food concentrations in the laboratory

Sea cucumbers (Cucumaria frondosa) (Echinodermata: Holothuroidea) held in flow-through tanks were exposed to different chloropigment concentrations by manipulating the seston concentration via the use of water filters in the inflow lines and the addition of cultured algae or natural plankton to tanks. The percentage of sea cucumbers open and feeding increased asymptotically as the seston chloropigment concentration increased. Below 50 μg·L-1 the percentage of sea cucumbers with tentacles extended and feeding decreased. The rate at which sea cucumbers inserted their tentacles into their mouths (0.96&plusmn0.34 insertion/min (mean&plusmnSD)) increased with increasing seston quality. Cucumaria frondosa fed at faster rates at the higher concentrations. There was a significant positive relationship between the stomach content (amount of chloropigment) of sea cucumbers and the seston chloropigment concentration to which they were exposed (r2 = 0.200, p<0.001).