2026/07/01 by Alessandro Balestrieri, Andrea Gazzola, Athina Papatheodoulou +3
Agricultural and Biological Sciences · Biochemistry, Genetics and Molecular Biology · #Fish Biology and Ecology Studies #Genetic and Clinical Aspects of Sex Determination and Chromosomal Abnormalities #Reproductive biology and impacts on aquatic species
paper · doi:10.1002/aqc.70423
openalex publication_date 2026/07/01 · openalex created_date 2026/07/15 · openalex updated_date 2026/07/29
ABSTRACT The European eel ( Anguilla anguilla ) has sharply declined throughout its range. Currently, little is known about its status in the Eastern Mediterranean. To address this gap, between 2020 and 2025 we surveyed 136 sampling river stretches in 31 river catchments of the Republic of Cyprus, combining electrofishing with habitat assessments. Eels were found in half of the catchments and at about one third of the sampling sites, mostly in river stretches downstream of dams. Overall, the species was assessed to occur in ca. 10% of the Republic's hydrographic network (ca. 200 km of river stretches). Only a few individuals were detected above dams, showing how barriers can strongly restrict their distribution. In the main rivers still supporting populations, dams prevent eels from accessing 70% of the river network (262 out of 380 km). Length–frequency analysis revealed up to 12 cohorts, which were grouped into five groups. Habitat models showed that water conductivity and distance from the sea best explained eel occurrence. Density models further highlighted ontogenetic shifts in habitat preferences: small eels were abundant near the coast, in warm, fast‐flowing waters, whereas larger ones were more frequent in shaded areas and sometimes associated with higher conductivity. We observed smooth changes across size classes, pointing to the importance of habitat diversity for supporting all life stages. Yet habitat loss due to dams, affecting habitat availability, remains a major constraint. Management should therefore focus on restoring river connectivity, for example, through eel ladders, and providing refuge habitats in downstream reaches that periodically dry.