Trends and variations in the baseline soundscape of America’s first offshore wind farm

Abstract

With the development of Cape Wind, Nantucket Sound, Massachusetts may become home to America’s first offshore wind farm. The goal of this ongoing project is to establish the baseline (pre-construction) soundscape of anthropogenic and biological activity, including diel and seasonal variability of various sound types, at the construction site and nearby comparison sites. Acoustic recorders have been deployed since April 2012, recording on a 10% duty cycle (sample rate: 80 kHz). Multiple fish sounds have been identified with the predominant signals attributed to cusk eels (Family Ophidiidae). Cusk eel sounds consist of a series of pulses, with energy between 400 and 2500 Hz. They are detectable from April to October, with dense choruses occurring during the summer months. Sound energy levels during these choruses increased near the hours of sunrise and sunset. Vessel traffic also showed diel and seasonal trends, with peaks during the daytime and in the summer. These trends in biological and human activity provide key baseline records for evaluating the possible influence of wind farm construction and operation on a local US soundscape.