Using Mobile Transect Surveys to Assess Biology within Potential Wind Energy Sites In North Carolina

Coastal wind resources available along the United States eastern seaboard represent a renewable energy alternative to fossil fuels.  However, wind turbines pose potential threats to aerial and aquatic organisms (e.g., birds, and fishes) because of the rotors needed for energy production and the foundation required for structural support.  To assess the species that could be affected by a proposed wind farm in a 62 km² region of eastern Pamlico Sound, NC we conducted weekly mobile hydroacoustic and visual surveys to simultaneously document the spatial and temporal variability in fish and avian assemblages in 2010.  We hypothesized that the distribution of fishes across the surveyed area would positively correlate with the density of piscivorous bird species.  A nMDS analysis of the avian dataset in PRIMER showed temporal shifts in bird abundance and species with a distinct cool (15 November – 1 April) and warm (2 April – 14 November) season (2D stress = 0.12).  Preliminary analyses of surveys containing both fish and avian data found a significant positive correlation between fish density and bird density in both cool (n = 25, r = 0.604, p = 0.0061) and warm (n = 47, r = 0.648, p = 0.0001) seasons.  Furthermore, we found a higher density of fishes (mean = 1.18, SE = 0.04 #· (m²)^-1) and birds (mean = 1.12, SE = 0.17 #·km^-1) during the cool season.  This was most notably driven by the presence and abundance of surface diving birds (e.g., cormorants, loons) and forage fishes (e.g., clupeids) documented using monthly experimental gillnet sets (May through December). Understanding the interaction between fishes and birds on a temporal and spatial scale should help guide the placement of future proposed wind farm locations in aquatic habitats.

Current address for M. W. Waine: Atlantic States Marine Fisheries Commission, 1050 N. Highland Street, Suite 200 A-N, Arlington, VA 22201