Records of four non-indigenous marine species, south of Koroni (Messiniakos Gulf, Peloponnese, Greece).
Caulerpa racemosa var. cylindracea (Sonder) Verlaque, Huisman and Boudouresque 2003 (Bryopsidales, Caulerpaceae), Percnon gibbesi H. Milne Edwards, 1853 (Decapoda, Plagusiidae) and Fistularia commersonii Rüppell, 1838 (Syngnathiformes, Fistulariidae) are reported from the coast, south of Koroni (Messinia, Greece). Sphyraena chrysotaenia Klunzinger, 1884 (Perciformes, Sphyraenidae) is recorded for the first time for this region. The crab Percnon gibbesi is very common along the coastal stretch northeast of Kalamaki beach, while regional observations of Caulerpa racemosa, Sphyraena chrysotaenia and Fistularia commersonii are occasional.