The first record of smallscale codlet, Bregmaceros nectabanus Whitley, 1941 (Teleostei: Bregmacerotidae) in Montenegrin waters and a review of previous Mediterranean records

Abstract

The smallscale codlet, Bregmaceros nectabanus Whitley, 1941, is a small gadiform fish native to the Indo-West Pacific and the Red Sea. It is considered non-indigenous in the Mediterranean Sea, with its first records appearing in the early 2000s. This paper reports the first confirmed occurrence of B. nectabanus in Montenegrin waters. The specimen was caught by beach seine in the interior of Boka Kotorska Bay at a depth of less than 20 m. Morphometric measurements were compared with existing Adriatic and Mediterranean records, revealing general consistency, although minor deviations were attributed to intraspecific variability, ontogeny, or ethanol-induced shrinkage. An updated overview of Mediterranean records from 2002 to 2024 is provided. While the overall distribution pattern supports a Lessepsian migration pathway, the occurrence of the species in areas of intensive maritime traffic suggests that secondary dispersal via ballast water may contribute to its spread. These findings extend the known range of B. nectabanus in the Adriatic Sea, indicating an ability to exploit shallow coastal environments. Further monitoring and genetic studies are recommended to clarify the mechanisms underlying its ongoing expansion.