This dataset presents findings from environmental impact assessments conducted from 2005 to 2023 in different OWFs of the BPNS. Samples were collected by means of Van Veen grab of 0.1m². Some samples belonging to the monitoring of one turbine (D5) in C-Power were collected by divers a differents distances (1, 7, 15, 25, 50, 100, 200 m) from the scour protection layer in 2010, 2011 and 2012. Subsamples of each Van Veen were taken for grain size analysis, and total organic matter content analysis. The remaining part of the Van Veen were sieved over a 1 mm sieve on board and stored in a 4% formaldehyde-seawater solution. In the laboratory, the samples were stained with 1% Rose Bengal, and rinsed over a 1 mm sieve. The organisms were counted and identified to the lowest possible taxonomic level (generally: species level). The organisms were also weighted using the ash-free dry weight (2005 to 2013) and the blotted wet weight (2014 onwards). The samples were then stored in a 4% buffered formaldehyde solution".