P.P. Shirshov Institute of oceanology Russian Academy of Sciences and
Istanbul University joined their efforts in the studies of the Sea of
Marmara ecological situation. Author investigated the ichthyoplankton
distribution and its species composition, ctenophore Mnemiopsis leidyi
and other jellyfish animals distribution. Mnemiopsis leidyi was distr
ibuted practically over the whole of the Sea of Marmara only in upper
layer to the depth 15 - 30 m. Its average biomass was 4.2 kg/m2. Small
and average size specimens prevailed, large ones were in the list. On
ly very scandy data are available in the Sea of Marmara ichthyoplankto
n. There weren't any ichthyoplankton in the upper layer. Fish eggs and
larvae of several species were found under termocline.