Macrobenthic fauna associated with maërl beds near aquaculture installations in the north-eastern Corinthian Gulf, Greece, with remarks on two taxa

Maërl beds, also known as rhodolith beds, are biogenic benthic habitats formed by unattached coralline algae and support diverse macrobenthic assemblages. In the Mediterranean, especially its eastern basin, information on their distribution, ecological condition and associated fauna remains limited. Maërl beds are sensitive to physical disturbance, sedimentation and organic enrichment, including pressures associated with aquaculture activities. This data paper describes the macrobenthic fauna associated with maërl beds located near and further from finfish farms in the Traxilos area of the north-eastern Corinthian Gulf, Greece. The dataset comprises eight sampling events and 328 abundance-based occurrence records representing 6,410 individuals. The paper also provides morphological notes on two polychaete taxa, Syllis nigricirris and the Neanthioides acuminata species complex, documenting variation in diagnostically relevant characters.