A Note on the Feeding, Growth, and Reproduction of the Epipelagic Scyphomedusa Pelagia noctiluca (Forskål)

Abstract

AbstractPelagia noctiluca is a common circumtropical, epipelagic scyphomedusa. It captures prey either on the ex- umbrella, tentacles, or oral arms. Ciliary activity and muscular contractions transport the prey proximally toward the stomach where the elongate gastric cirri attach to it and digestion begins. Prey of P. noctiluca medusae collected in inshore waters of Puerto Rico consisted of a wide variety of zooplankton (e.g., hydromedusae, ctenophores, copepods, chaetognaths, and fish eggs). The ability of P. noctiluca to feed on both large and small prey species is adaptive in the open ocean where prey are taxonomically variable and of a broad size range. Pelagia noctiluca medusae were maintained in the lab for more than 20 days. A biomass doubling occurred in 14 days. The medusae consumed food equaling 60% of their wet weight per day. Growth efficiency was 10%. Starvation weight loss was >50% in 7 days. Because P. noctiluca often occurs in dense swarms, they can consume large amounts of prey in a short...