Discovery of the Mud Crab Dyspanopeus sayi (S.I. Smith, 1869) (Brachyura: Xanthoidea: Panopeidae) in the Sea of Azov

In August 2022, the mud crab Dyspanopeus sayi (S.I. Smith, 1869) was recorded for the first time in waters of European Russia: in the coastal zone of Cape Kazantyp (Shelkovitsa Bay) at the northern coast of the Kerch Peninsula and in the vicinity of the Arshintsevskaya Spit (Kerch). The native range of this species stretches along the entire Atlantic coast of North America, and its invasive range encompasses coastal waters of the Atlantic coast of Europe, the northern part of the Mediterranean Sea, and the western part of the Black Sea. In 2009, D. sayi was first discovered in the Black Sea near the coast of Romania and has significantly expanded its distribution range in the Azov-Black Sea basin over the past 10 years. Most probably, the species spreads with ballast waters of ships; however, it cannot be ruled out that crab larvae migrate with marine currents. The presence of egg-bearing females and individuals of various sizes can indicate that D. sayi has naturalized in coastal areas of the Sea of Azov. D. sayi is an active invader colonizing transitional waters between continental water bodies and the sea. Therefore, the distribution of this crab must be closely monitored to forecast potential consequences for local species and ecosystems.