Invasion

Invasion Description

Based on the abundance of polyps and medusae in the Black Sea coast swamps on the Bulgarian coast, Thiel (1935) considered that it was part of an endemic 'Sarmatic' cnidarian fauna, and only recently introduced to the United States. This was based on B. virginica's absence in early American collections (of Agassiz, Fewkes, Hargitt, etc.), and the lack of records of polyps from North America. Blackfordia virginica's native distribution includes the Sea of Azov (Naumov 1969; Thiel 1935), but canals enabled it to invade the Caspian Sea in 1956 (Logvinenko 1959). It should be noted that Russian and Ukrainian workers consider B. virginica to be of Northwest Atlantic origin, and introduced to the Black Sea (Mordukhai-Boltovskoi 1964; Shadrin 2000; Gomiou et al. 2002). Provisionally, we are following Mills and Sommer (1995) and Ruiz et al. (2000) in treating this species as an invader of Black Sea origin.

Geographic Extent

Bulgaria/Black Sea (Theil 1965); Russia-Ukraine (Naumov 1969)