underwater sound reference division ultrasound

“ Noise emission during the first powerboat race in an Alpine lake and potential impact on fish communities,” J. “Port industry statistics,”, 1 p (Last viewed October 25, 2013).Īmoser, S., Wysocki, L. Rock fracturing produced a source level of 175 dB, whereas six distinct sources associated with rock excavation had source levels ranging from 164.2 to 179.4 dB re 1 μPa-1 m (rms).Īmerican Association of Port Authorities. The strongest sound sources (180–188.9 dB) were emitted by commercial shipping. Source levels (dB re 1 μPa-1 m rms) were back calculated using fitted regression (15LogR). To address concerns for protection of fishery resource occupying the harbor, SPL were examined at frequency bands of 50–1000 Hz and 100–400 Hz, the ranges where the majority of fishes without hearing specializations detect sound and the range of greatest sensitivity, respectively. Results are presented as sound pressure levels (SPLs) in one-third octave versus range across the 20 Hz to 20 kHz frequency band. To place sound emitted from these dredges in perspective with other anthropogenic sounds, recordings were also made of several deep-draft commercial vessels. Sound sources included rock fracturing by a hydraulic cutterhead dredge and six distinct sources associated with a mechanical backhoe dredging operation during rock excavation. Sound recordings were made of two dredging operations at hydrophone depths of 3 and 9.1 m at distances up to 1.2 km from the source in shallow waters (<15 m) of New York Harbor.

Underwater sound reference division ultrasound