Sampling Methods Van Veen grab with a sampling area of 1/20 m2 was employed as a macrozoobenthos sampler. Study Extent Data were obtained from sampling analysis from 2011 to 2015. Macrozoobenthos data collected in the northern part of the Romanian littoral (Danube mouths) between 2011-2015. Method step description: The samples were washed onboard through a 0.5 mm mesh sieve. Each sample was subsequently washed in the laboratory through a 1.0 mm and 0.5 mm mesh sieve. Each sample fraction was sorted under a stereomicroscope (OLYMPUS SZX10 - zoom range of 0.63x to 6.3x). All taxa were identified to the lowest possible taxonomic level (e.g. species) and all names were updated according to the World Register of Marine Species (WoRMS).