Gastric emptying, clearance rate, feeding periodicity and food consumption of the Black Sea jelly fish, Mnemiopsis leidyi (Agassiz)

Abstract

The feeding physiology of Mnemiopsis leidyi fed on Artemia salina were investigated under laboratory conditions. Multifactorial experimental designs were used to study the factors affecting gastrovascular emptying in M. leidyi. A high correlation was found between number of prey ingested and digestion time. Modelling of gastric emptying time (GET, h.) of M. leidyi fed on A.salina was attempted to describe the effect of animal size, prey number, container volume and temperature on the digestion time. GET= 3.42- 0.00636 W + 0.0121 pN - 0.155 V - 0.00983 T. The clearance-rate was significantly affected by container volume and the feeding time. Multiple regression was attemped to model clearance rate: CR = 0.366 + 0.377 V - 0.197 H. Studying the feeding periodicity over a 24 h period, it was found that under laboratory condition and with readily available prey, M. leidyi feeds continuously except for the early hours of the day. Under such conditions medium size Mnemiompsis (11.36±0.38 g) consumed between 1286 and 2741 artemia daily. With the models of gastric emptying time (GET) and clearance rate (CR) presented in this study, quantitative assessment of the predatory impact of the ctenophore Mnemiopsis leidyi on the Black Sea ecosystem can be faciliated.