The Feeding and Growth of the Sea Nettle, Chrysaora quinquecirrha (Desor), in the Laboratory

Abstract

The sea nettle,Chrysaora quinquecirrha, can capture ctenophore prey on its exumbrella, tentacles, and oral arms. Once attached to the medusa, the prey is transferred to the oral arms, where it becomes enveloped by the lip-like folds of the oral arms. The oral arms move the prey as far proximally as possible by ciliary creeping and muscular contractions. If the prey is too large to enter the stomach, it is digested within the oral arms by extracellular, proteolytic enzymes that probably originate from the gastrodermis of the oral arms and/or from the gastric cirri. Several large ctenophores can be digested simultaneously, owing to the extensive surface areas of the oral arms. Of the threeC. quinquecirrha medusae maintained in the laboratory for up to 60 d, the smaller two specimens (25–150 g wet weight) showed a biomass doubling in ∼14 d; the largest specimen (300 g), a sexually mature female, showed little growth but did release >100 ova 24 h−1. Growth efficiencies were estimated to be ∼2% for the largest specimen (not including biomass of gametes) and ∼10% for the smaller two specimens. These growth efficiencies are comparable to those of other gelatinous predators.