Abstract: (2728 Views)
The Caspian Sea ecosystem has been suffered from many problems since 1980s. Owing to the significance of zooplankton communities in marine ecosystems, the state of the fluctuations of Copepoda and Cladocera species and their relationship with Ctenophora was investigated in southern Caspian Sea. This study were evaluated at the depths 5, 10, 20 and 50 m in the southwestern Caspian Sea between 1996 and 2013. A decline in zooplankton species was observed before 2000 and continued until 2013. Only four of ten Cladocera species recorded during 1996/1997 were found in 2013. Of the seven Copepoda species recorded during 1996/1997, only three species of Copepoda, were recorded after 2000. The findings revealed no decrease of Acartia tonsa detected during the blooming period of Mnemiopsis leidyi after 2001 until 2013. No negative impact of M. leidyi was verified on the A. tonsa by comparing the annual average of A. tonsa abundance in 1996/1997, before the invasion of M. leidyi, and after the invasion during 2001 to 2013. The dominance of M. leidyi population had <5 mm length which feeding only microplankton as protozoa, dinoflagellates and small diatoms. Climate change, overfishing, and pollutants increase might play important roles in enhancement of zooplankton population and loss of endemic species in the Caspian Sea.
Type of Study:
Research |
Subject:
Special Published: 2019/06/22