Age and growth of European eel, Anguilla anguilla (Actinopterygii, Anguilliformes, Anguillidae), in the Karavasta Lagoon, Albania

The European eel, Anguilla anguilla (Linnaeus, 1758), is a critically endangered species with a complex life cycle affected by many environmental factors. Its high flexibility in several biological parameters emphasizes the need for regional management strategies. To support management and population modeling, a study was conducted on the age, growth, and other biological characteristics of eels in a coastal lagoon—this being the first study of its kind conducted in the southwest of the Adriatic Sea for the European eel to date. A total of 435 silver eels were collected from commercial catches in the Karavasta Lagoon, Albania, at the start of their migratory journey from 2022 to 2024. The length–weight relationships revealed distinct growth patterns for both males ( b = 2.8) and females ( b = 2.7), indicating negative allometric growth. The ages of silver eels ranged from 4 to 11 years, with males averaging 6.2 years and females 7.0 years, the latter being significantly older. Throughout their lives in the lagoon, females also exhibited a higher mean annual growth in length (6.4 cm) compared to males (5.7 cm). Swim bladders of all eels were free from infection with Anguillicola crassus , a common and widespread nematode parasite. These results offer important insights into eel population dynamics in transitional waters and form the basis for conservation efforts in Adriatic Sea ecosystems. These data are vital for creating sustainable management strategies, mainly due to the decline in eel populations.