Feeding and metabolism of the jellyfish Pelagia noctiluca (scyphomedusae, semaeostomae)

Abstract

Laboratory experiments were carried out on the holoplanktonic scyphomedusa Pelagia noctiluca, which exhibits population explosions some years in the Mediterranean Sea. Feeding experiments performed on small, laboratory-reared medusae showed specific daily rations of 13 and 35% at 5 and 20 Anemia nauplii prey 1-1 respectively, while basal NH+4 excretion reached 3.9% (specific elemental metabolic rate) for adults at 22°C. These values appear to be consistent with those previously observed by several authors for other planktonic coelenterates. Assuming that such laboratory physiological rates are indicative of food requirements in natural environments, and given the high abundance of P. noctiluca observed regionally, we conclude that P. noctiluca can have a strong predatory impact in the Ligurian Sea (north-west Mediterranean), particularly during the summer and early fall. © 1987 IRL Press Limited.