Abstract
Two new fish species were recorded while monitoring the fish fauna of Sukhyi Lyman (or Sukhyi Estuary), an estuary in the northwestern Black Sea (Ukraine) close to the marine port of Chornomorsk. A single pumpkinseed, Lepomis gibbosus (Linnaeus, 1758), was observed in May 1999, followed by numerous observations in May 2021, while a single peacock blenny, Salaria pavo (Risso, 1810), was photographed during snorkeling observations in September 2021. The estuary is a known hub for invasive alien species and other neobionts due to the presence of the marine port. The new population of pumpkinseed, a North American invasive species, in the estuary represents the next stage in the species’ ongoing expansion along the Ukrainian Black Sea coast. Likewise, the appearance of the peacock blenny represents the latest stage in the “Mediterranization” of the Black Sea, a process that has been ongoing over the last several thousand years.