Mnemiopsis leidyi

Even species that are not known to produce bioactive metabolites may have a large environmental impact, such as Emiliania huxeleyi. This haptomonad protist blooms periodically in the Bering Sea at the detriment of diatoms, disruptii the food chain with massive death of migratory birds and fish losses. Mnemiopsis leidyi is another major such problem this comb jelly has invaded the Black Sea, subtracting zooplankton to fish. 

Indices of condition like those mentioned above have also been used in studies of other water organisms. The food available to the medusa Aurelia aurita and the ctenophore Mnemiopsis leidyi can be judged from their level of carbohydrates (Anninsky, 1990), and that available to copepods such as Calanus helgolandicus can be judged from their content of neutral lipids, especially wax esters (Yuneva and Svetlichny, 1996). 

In August 1988, a new Black Sea invader - the ctenophore Mnemiopsis leidyi - appeared in the Sea of Azov it was first encountered near the Kerch Strait in the southern and eastern parts of the sea. From that time, every spring or summer, Mnemiopsis leidyi has penetrated into the Sea of Azov from the Black Sea with currents to provide an outburst in its development in the summer or early autumn. Then, it became extinct at the temperature drop below 4 °C at the end of October to November [28]. Mnemiopsis leidyi negatively affected the ecosystem of the Sea of Azov and undermined its fish stocks. 

The cold period of 1985-1993 and the subsequent steady-state growth in SST were accompanied by important changes in the Black Sea ecosystem. For example, the cold winters of 1985 and 1987 seem to oppose the mass development of the ctenophore Mnemiopsis leidyi, which invaded into the Black Sea in 1982-1983 [17]. A sharp decrease in its biomass that followed its mass... 

Fig. 2 Interannual variations of the abundance of Mnemiopsis leidyi (gm 2) in August-September (abundance was estimated with coefficient for insignificant catchability (in mean 2) after Vinogradov [35]) and average surface water temperatures (direct measurements)...

Fig. 5 Fish catch after Mnemiopsis leidyi outbreak but before B. ovata development...

The ctenophore Mnemiopsis leidyi is the most impressive representative of invaders it is the most aggressive invader, which expanded over all the seas of the Mediterranean basin and over the Caspian Sea and affected their ecosystems. The subsequent introduction of Beroe ovata to the Black Sea provided the beginning of restoration of its ecosystem. 

Purcell JE, Shiganova TA, Decker MB, Houde ED (2001) In Purcel JE, Graham WM, Dumont HJ (eds) The ctenophore Mnemiopsis leidyi in native and exotic habitats U.S. estuaries versus the Black Sea basin. Hydrobiologia. 451. Kluwer, Dordrecht, p 145... 

Total number of aliens in the Sea of Azov comprised 46 species. When analyzing the ecological role of species-invaders in the Sea of Azov, one should first mention the enormous negative effect at all the levels of its ecosystem, fish resources included, caused by the invasion of the predator ctenophore Mnemiopsis leidyi. 

In the field of biology, the most urgent is the estimation of the present-day condition and productivity of the Black Sea biota after the long-term impact of the invader ctenophore Mnemiopsis leidyi and of the recent invader, ctenophore Beroe ovata. 

Great South Bay, NY scyphozoan medusae and Mnemiopsis leidyi ctenophores Mnemiopsis leidyi ctenophores and 1-3 (summer) Park and Carpenter (1987)... 

Narragansett Bay mixed zooplankton >200 pm Mnemiopsis leidyi ctenophores 39 (spring) 3-15 Kremer (1975)... 

Kremer, P. (1975). Mineral cychng in southeastern ecosystems. In Nitrogen Regeneration by the Ctenophore Mnemiopsis leidyi" (Howell, F. G., Howell, J. B., and Smith, M. H., eds.). ERDA Symposium Series (Conf-740513), Kingston, Rhode Island, pp. 279—290. 

Kremer, P. (1977). Respiration and excretion by the ctenophore Mnemiopsis leidyi. Mar. Biol. 44, 43-50. 

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