Marbled Spinefoot Siganus rivulatus (Siganidae)—A New Alien Species in the Black Sea

A specimen of the marbled spinefoot Siganus rivulatus Forsskål & Niebuhr, 1775, a new fish species for the Black Sea, was caught on November 10, 2020, in the waters of Dvuyakornaya Bay near the city of Feodosiya in the northeastern part of the Black Sea. The 2-year-old fish had a total body length of 124.2 mm and height of 35.7 mm. The morphology of the main elements of the fish’s body and its teeth are described. The path of spreading of this species from its native range (western part of the Indian Ocean) to the Mediterranean and Black seas has been traced. The potential place of this species in the Black Sea ecosystem is discussed.