Echo - physiological characteristics of Mnemiopsis leidyi (Ctenophore) and Rhizostoma pulmo (Scyphozoa) in Black Sea Ecosystem

In this study, the emptying physiology of Mnemiopsis leidyi and Rhizostoma pulmo fed on Artemia salina, Raphana thomasiana larvae respectively in the laboratory conditions were investigated. The factors affecting gastric emptying in both jelly fish were studied using multifact oriel experimental designs. It was found that there is a high correlation between number of prey ingested and gastric emptying time (GET). Gastric emptying in Mnemiopsis leidyi fed on Artemia salina was best describes by using exponential model. GET= 3.42- 0.00636 W + 0.0121 pN - 0.155 V - 0.00983 T The clearance-rate was also modelled as, C.R.= 0.366 + 0.377 V - 0. 197 H The study has shown that there is a good correlation between initial number of prey items and clearance-rate in Rhizostoma pulmo. Gastric emptying time of Rpidmo fed on Rapana thomasiana was significant affected by umbrella diameter of R.pulmo. The feeding periodicity of M. leidyi fed on A.salina over the 24 h. period was also studied. It was found that these animals at laboratory condition feed opportunistically such that when prey are readily available feeding occurs all day through except early hours of the day. Key Words : Mnemiopsis leidyi, Rhizostoma pulmo, Clearance-rate, Gastric emptying, Food consumption VII