The occurrence of Eriocheir sinensis H . Milne Edwards , 1853 ( Crustacea : Brachyura : Varunidae ) from the Caspian Sea region , Iran

Eriocheir sinensis H. Milne Edwards, 1853 has been introduced and established mainly in North East Europe and San Francisco Bay, United States from native China. This note records the first specimen of the Chinese mitten crab from the River Tazeh Bekandeh, Caspian Sea collected on 26 October 2002.


Introduction
Eriocheir sinensis H. Milne Edwards, 1853 was introduced into Germany in 1912 (Panning 1939) from China by ships' ballast water and has spread subsequently throughout northern Europe.The present estimated distribution of established populations ranges from Finland (Haahtela 1963) in the north, through Sweden, Russia, Poland, Germany, the Czech Republic (Prague), Netherlands, Belgium and England, to France.Although recorded from near Oslo, Norway, this species has not become established (Christiansen 1977).The southernmost Atlantic coast record was the Golfe de Gascogne (Vigneux et al. 1993), France, and the crab extended its range via the Garonne canal system to Sigean (Petit 1960), Languedoc-Roussillon, a Mediterranean district of southern France, although it did not become established (Petit and Mizoule 1974).However, Cabral and Costa (1999) collected mitten crabs from the Tagus River, Lisbon, Portugal and this is the most southerly European record for E. sinensis to date.But further towards the eastern boundaries of Europe, populations of mitten crab appear to have become established in the Black Sea (Zaitsev and Öztürk 2001), and the Sea of Azov (Murina and Antonovsky 2001).Recent captures from this region include mitten crabs from the Volga River Delta and, the Cheboksary and Rybinsk Reservoirs (Slynko et al. 2002).
The crab has also been reported from North America with records from the Detroit River at Windsor Ontario and Lake Erie (Nepszy and Leach 1973), and recently the St. Lawrence River (de Lafontaine 2005) Canada, the Mississippi Delta (Horwath 1989), and San Francisco Bay (Cohen and Carlton 1997), United States.Eriocheir sinensis has now become well established in California.
To complete this synopsis, according to Mayumi Uchida (pers.comm.via Stephan Gollasch) two crabs were collected in Tokyo Bay during 2004.The purpose of this note is to record the first mitten crab from the Iranian coast of the Caspian Sea.

Discussion
According to Aladin et al. (2002), nineteen alien species, believed to be ship-transported, have already established viable populations in the Caspian Sea since the opening of the Volga-Don Canal half a century ago.Although the canal is closed to commercial traffic between November and April, an estimated 400,000 ships have transversed this stretch of water in the last fifty years (Galil and Olenin 2002).However without DNA samples, the origins of the Iranian mitten crab can only be speculative as the Caspian is connected to Baltic Sea in the north and the Sea of Azov in the west.Both these areas have been invaded by Eriocheir sinensis.As for the establishment of a viable population of mitten crabs in the Caspian, this is debatable.Anger (1991) suggests that at suitable temperatures mitten crab first stage zoeas can tolerate salinities between 10 and >30‰, although the extremes cause increases in mortalities.The salinity of the Caspian Sea is ca.12‰.

Figure 1 .
Figure 1.Eriocheir sinensis H. Milne Edwards, 1853: dorsal view of male specimen collected from Northern Iran.Taken by Phil Hurst, NHM Photo Unit

Figure 2 .
Figure 2. Eriocheir sinensis H. Milne Edwards, 1853: ventral view of male specimen collected from Northern Iran.Taken by Phil Hurst, NHM Photo Unit