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With the arrival of the invasive comb jelly Mnemiopsis leidyi in the Caspian Sea in 1991, extensive changes have been occurred. Therefore, this project aims to investigate the comb jelly M. leidyi monitoring and rearing in the southern Caspian Sea in 2013. To survey of M. leidyi and zooplankton abundance and biomass, sampling was carried out during the four seasons at spring, summer, autumn and winter in 4 half-transect (Anzali, Tonekabon, Noshar and Amirabad) and also samples for the ctenophore rearing was done at depths of 5, 10 and 20m. Sampling was performed with a 500 and 100 μ plankton net vertically at layers of 0-5, 0-10 and 0-20 m. 12 aquaria of 50 L volume were designed with salinity of the Caspian Sea to study the breeding and fecundity with aeration. 3 of aquariums with salinity of 9±1pp, 3 with 11±1ppt and 3 of 12±1 ppt filled with Caspian Sea water. Water temperature in each of the three treatments was set in 20±2oC, 23±2^oC and 25±2^oC. 3 of aquaria were set at the salinity of 12.5 ppt and at the same temperature of the Caspian Sea (20, 23, 25^oC) as control. Mean annually Mnemiopsis abundance and biomass were 16.8±1.5 ind.m^3 (139.5±41.1 ind.m^2) and 1.9±0.1 g.m^3. (5.3±0.7 g.m^2). Maximum mean abundance was recorded in autumn with 36.6.7±13.8 ind.m^3 (355.1±103.6 ind.m^2) and maximum biomass was observed in summer of 1.9±0.2 g.m^3(15.0±1.5 g.m^2). Minimum mean abundance was found in spring with 1.3±0.5 ind.m^3 and minimum biomass was in winter of 0.01±0.005 g.m^3. Regional distribution of M. leidyi in the southern Caspian Sea showed aggressive area in terms of density and biomass are areas with significant differences (P |
