Survey to establish the infaunal species composition and sediment properties of maerl bed habitats in Falmouth Harbour, from SCUBA diver collected core samples. Surveys were conducted in response to proposed dredging activities to deepen the shipping channel. Core samples collected by divers September - November 2012 and July - August 2013 were used to assess habitat quality and species distribution by quantifying the abundance of infauna and analysing organic content, particle size and maerl structure. There were 6 sites divided into three 5m2 plots. SCUBA divers collected 8 maerl core samples per plot: 5 cores for faunal analysis and 3 cores for sediment and organic content analysis.