Effect of Destroy Mnemiopsis Leidyion Zooplan Population in the Caspian Sea

Mnemiosis leidyi is one the species of com-jelly. It belongs to the Ctenophore type, Lobata order. It is a purely marine, free-swimming animal with a transparent jelly-like walnut-shaped body. The alien ctenophore Mnemiopsis which was transported from the Black Sea into Caspian at the end of 1990s has been negatively affecting ecosystem in this new environment. This speices is food rival of pelagic fish. The Ctenophore was decreased sharp Zooplankton and pelagic fish stock. In this study, sampling done from Mnemiopsis leidyi, Zooplankton, spatial and temporal M.leidyi feeding were studied from a total of 8 stations located along two transects (Anzali, Khazarabad) in the Iranian Coasts of the Caspian Sea. During December 2003 to March 2005. Copepoda were been dominant zooplankton in the Iranian coasts of the Caspian sea, from this order was identificated Harpocticode, Calanuide and Cyclopoida. The Maximum of zooplankton abundance achieved with mean 29368 N/m3 in winter and zooplankton achieved minimum with value 9166 Nm3 in summer (Anzali region). In Khazarabad maximum zooplankton abundance measured with value 1616 N/m3 in spring and minimum zooplankton has been 8468 n/m3 in summer. Study Mnemiopsis stomach showed. The highest food frequency were observed Acartia, A.egg, lamlibranch, Balanus nauplii and Tintinnopsis, So M.leidyi gut showed, Fish larve, Crustacea larvae, Cladocera and Chironomid larvae. These results showed, the main food Ctenophore were been Acartia. After invasive Ctenophore sharp decreased zooplankton population.

کلیدواژه ها:

Mnemiosis leidyi ، Zooplankton ، Caspian ، Clupeonella ، Food