DOI: 10.1007/698_2006_066 Date: 2007-01-15 Proof-Number: 1 uncorrected proof Hdb Env Chem Vol. 5, Part (0000): 1–x DOI 10.1007/698_5_066  Springer-Verlag Berlin Heidelberg 2007 Published online: 2007 Introduced Species Tamara Shiganova P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, 36 Nakhimovsky Pr., 117997 Moscow, Russia shiganov@ocean.ru 1 Introduction ................................... 2 2 Microplankton .................................. 3 3 Marine Fungi .................................. 3 4 Phytoplankton .................................. 4 5 Macrophytes ................................... 6 6 Zooplankton ................................... 7 7 Benthos ..................................... 12 8 Fishes ....................................... 17 9 Pathways of Penetration of Alien Species ................... 22 10 Vectors (Ways) of Alien Species Penetration ................. 25 11 Conclusions ................................... 28 References ....................................... 29 Abstract Due to increasing human activities such as shipping, deliberate stocking, and accidental introduction, a high number of alien species have become established in the Black Sea over the last century. In addition, global warming facilitates the population in- crease of thermophilic species and their northward expansion from the Mediterranean. As a result, the Black Sea became a pivotal recipient area for marine and brackish water aliens. It infects all other seas of the Mediterranean basin and the Caspian Sea as a donor. Species that have become abundant in all these seas are euryhaline and rather euryther- mic, and are widely distributed in the coastal areas of the world’s oceans. As a rule, they are mass or dominant in their native habitats, where they sometimes cause outbreaks. CE a Such species, with wide environmental tolerance and high phenotypic variability, have developed in mass and first became dominant in the Black Sea, and from here they spread to the Sea of Azov and became established in the Caspian and even the Aral Sea. The most euryhaline species also spread south to the Marmara and eastern Mediterranean (mainly the Aegean and Adriatic) Seas. They often greatly affected the recipient ecosystems, first of all the communities in the tropic level they occupy themselves, and thereafter some of them other trophic levels of the ecosystem; and finally, could cause changes in ecosystem functioning and a fundamental rearrangement of the original energy fluxes. The Black CE a Author: Please clarify the use of the word “mass” - all cases Editor’s or typesetter’s annotations (will be removed before the final T E X run)