Patterns and mechanisms of aquatic invertebrate introductions in the Ponto-Caspian region

Abstract

The Black, Azov, and Caspian sea drainages (i.e., Ponto-Caspian region) have an extensive and long history of species introductions. Here we review patterns and mechanisms of introductions of aquatic invertebrate species into these ecosystems. Since the late 1800s, 136 free-living and 27 parasitic invertebrate species have been introduced outside their native ranges and have established reproducing populations in the Ponto-Caspian region. The bulk of these introductions are represented by crustaceans (53%), flatworms (15%), and molluscs (13%). Most of the introduced species are native to other areas within the Ponto-Caspian region (37%), with other sizable contributions from the Atlantic–Mediterranean (15%) and boreal European–Siberian (14%) geographic regions. Mechanisms of introductions were dominated by deliberate releases (29%) and shipping activities (22%), with the former occurring principally in freshwater habitats and the latter in marine and estuarine ones. Other introductions resulted from unintentional release (21%) and hydrotechnical development (14%), notably the construction of reservoirs and canals. Global and regional trade, particularly that mediated by commercial ships, provides dispersal opportunities for nonindigenous invertebrates to and within the Ponto-Caspian region, rapidly changing the composition of its endemic fauna.

Anthropogenic Effects of Reservoir Construction on the Parasite Fauna of Aquatic Wildlife

“…These changes have serious effects on the abundance and species composition of parasites (Izyumova, 1979(Izyumova, , 1987. In addition, the anthropogenic movement of fish and invertebrates into new reservoirs creates additional problems because they introduce new parasites to the indigenous fauna that may lead to epizootic outbreaks of disease (Hoffman and Bauer, 1971;Grigorovich et al, 2002). The detailed changes in the parasite fauna that occur during the reservoir formation period are dependent on the types of life cycles they use (see below).…”

Dispersal of the Ponto-Caspian amphipod Echinogammarus ischnus: invasion waves from the Pleistocene to the present

“…Many organisms endemic to the Ponto-Caspian region are currently involved in range expansions, and have colonized Eastern and Western Europe, including the Baltic Sea (Bij de Vaate et al, 2002;Grigorovich et al, 2002). After a first wave of expansion in Europe, several of these invaders including fishes (Proterorhinus marmoratus, Neogobius melanostomus), mussels (Dreissena polymorpha, Dreissena bugensis), and crustaceans (Cercopagis pengoi, Echinogammarus ischnus) have reached the Great Lakes via ballast water discharge, triggering a secondary wave of dispersal in North America .…”

Bryozoa of the southern Caspian Sea, Iranian coast

“…The low salinity and longterm isolation of this lake created suitable conditions for only a few inhabitants, among which are a small number of bryozoan species (Karpinsky 2005). The Black, Azov and Caspian seas (Ponto-Caspian Basin) were separated and reconnected several times during geological history, and construction of Volga-Don shipping canal caused anthropogenic reconnection of these seas in 1952 (Grigorovich et al 2002, 2003, Riedel et al 2006, Panov et al 2007, Shiganova 2010. Gontar (2010) described a new cheilostome species, Lapidosella ostromuovi, from the Sea of Azov.…”