Unexpected occurrence of the Japanese amberjack Seriola quinqueradiata in the Mediterranean Sea: First record and possible introduction pathways

Abstract

The introduction of non-indigenous species (NIS) into the Mediterranean Sea represents a growing ecological concern, driven by multiple vectors including shipping, aquaculture, and climate-mediated range expansions. In this study, we report the first Mediterranean record of the Japanese amberjack Seriola quinqueradiata Temminck & Schlegel, 1845 (Carangidae), a species native to the northwestern Pacific Ocean. A specimen was captured by an angler on 13 February 2026 along the coast of Nardò (Ionian Sea, Italy), near Zone C of the Porto Cesareo Marine Protected Area. Species identification was confirmed through an integrative taxonomic approach combining morphological examination and mitochondrial COI gene barcoding. A second specimen, likely belonging to the  same species, was captured shortly thereafter in the same area. The most plausible introduction pathways were discussed. This finding highlights the importance of continuous monitoring of marine biodiversity, particularly through the integration of citizen science and fisheries observations, which are essential for the early detection of rare and potentially invasive species.