(2008). MARINE MAMMAL NOISE-EXPOSURE CRITERIA: INITIAL SCIENTIFIC RECOMMENDATIONS. Bioacoustics: Vol. 17, No. 1-3, pp. 273-275.

Marine mammal noise-exposure criteria: initial scientific recommendations

The effects of noise on man

Combining calibrated hydrophone measurements with vessel location data from the Automatic Identification System, we estimate underwater sound pressure levels for 1,582 unique ships that transited the core critical habitat of the endangered Southern Resident killer whales during 28 months between March, 2011, and October, 2013. Median received spectrum levels of noise from 2,809 isolated transits are elevated relative to median background levels not only at low frequencies (20-30 dB re 1 µPa(2)/Hz from 100 to 1,000 Hz), but also at high frequencies (5-13 dB from 10,000 to 96,000 Hz). Thus, noise received from ships at ranges less than 3 km extends to frequencies used by odontocetes. Broadband received levels (11.5-40,000 Hz) near the shoreline in Haro Strait (WA, USA) for the entire ship population were 110 ± 7 dB re 1 µPa on average. Assuming near-spherical spreading based on a transmission loss experiment we compute mean broadband source levels for the ship population of 173 ± 7 dB re 1 µPa 1 m without accounting for frequency-dependent absorption. Mean ship speed was 7.3 ± 2.0 m/s (14.1 ± 3.9 knots). Most ship classes show a linear relationship between source level and speed with a slope near +2 dB per m/s (+1 dB/knot). Spectrum, 1/12-octave, and 1/3-octave source levels for the whole population have median values that are comparable to previous measurements and models at most frequencies, but for select studies may be relatively low below 200 Hz and high above 20,000 Hz. Median source spectrum levels peak near 50 Hz for all 12 ship classes, have a maximum of 159 dB re 1 µPa(2)/Hz @ 1 m for container ships, and vary between classes. Below 200 Hz, the class-specific median spectrum levels bifurcate with large commercial ships grouping as higher power noise sources. Within all ship classes spectrum levels vary more at low frequencies than at high frequencies, and the degree of variability is almost halved for classes that have smaller speed standard deviations. This is the first study to present source spectra for populations of different ship classes operating in coastal habitats, including at higher frequencies used by killer whales for both communication and echolocation.

Ship noise extends to frequencies used for echolocation by endangered killer whales

The Heard Island Feasibility Test source transmitted a hum at 209–220 dB re: 1 μPa at 175‐m depth, centered on 57 Hz with a maximum bandwidth of 30 Hz for 1 h of every 3. Experienced marine mammal observers conducted line‐transect surveys and monitored marine mammal behavior visually and acoustically in a 70×70 km square centered on the transmission site. Thirty‐nine groups of cetaceans and 19 of pinnipeds were sighted from both vessels before the start of transmissions. Thirty‐nine groups of cetaceans and 23 of pinnipeds were sighted during transmissions. Blue (Balaenoptera musculus), fin (B. physalus), and sperm (Physeter macrocephalus) whales were sighted during the base line period; blue, sperm, and possibly sei (B. borealis) whales were sighted during the transmission period. More schools of hourglass dolphins (Lagenorhynchus cruciger) were sighted during transmissions, but fewer groups of pilot whales (Globicephala melas), southern bottlenose whales (Hyperoodon planifrons), and minke whales (B. acutorostrata). The density of all cetaceans was 0.0157 groups/km2 before the transmissions and 0.0166 groups/km2 during. Antarctic fur seals (Arctocephalus gazella) and southern elephant seals (Mirounga leonina) were seen, but not in sufficient numbers to estimate abundance. One blue whale tracked before, during and after a transmission changed respiration and reorientation rates, but did not avoid the source detectably. Sperm whales and pilot whales were heard in 23% of 1181 min of baseline acoustic surveys; but in none of 1939 min during the transmission period. Both species were heard within 48 h after the end of the test.

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Relative abundance and behavior of marine mammals exposed to transmissions from the Heard Island Feasibility Test

Stafford, K.M., C.G. Fox, and D.S. Clark. 1998. Long-range acoustic detection and localization of blue whale calls in the northeast Pacific Ocean. Journal of the Acoustical Society of America

Marine Mammals and Low-frequency Sound: Progress Since 1994

The study compares the relative magnitudes and effects on marine mammals of noise from oil and gas industry activities with noise from other sources in Alaska OCS and coastal waters. The study procedure incorporates the receiver, source and path concepts generally used in acoustic analysis. The receiver characterization includes a review of marine mammal distribution in Alaska and a map of the distribution of each major species. Information on species sound production, hearing sensitivity (when known), and observed responses to noise sources is also included. The analysis of noise sources found in the Alaskan marine environment considers natural, industrial, transportation, and cultural sources. Acoustic transmission loss characteristics obtained from measurements and model predictions are used to estimate the effective ranges of the noise sources using available source level information. Information on species distribution was combined with information on source distribution, source level, and transmission loss to determine the most significant sources in terms of their acoustic range and the numbers of mammals potentially affected by developing a Standardized Noise Contribution Model species.

Analysis and ranking of the acoustic disturbance potential of petroleum-industry activities and other sources of noise in the environment of marine mammals in Alaska. Final report

Research was performed during the first year (1985) of the two-year project investigating potential responsiveness of bowhead and gray whales to underwater sounds associated with offshore oil-drilling sites in the Alaskan Beaufort Sea. The underwater acoustic environment and sound propagation characteristics of five offshore sites were determined. Estimates of industrial noise levels versus distance from those sites are provided. LGL Ltd. (bowhead) and BBN (gray whale) jointly present zones of responsiveness of these whales to typical underwater sounds (drillship, dredge, tugs, drilling at gravel island). An annotated bibliography regarding the potential effects of offshore industrial noise on bowhead whales in the Beaufort Sea is included.

Prediction of drilling site-specific interaction of industrial acoustic stimuli and endangered whales: Beaufort Sea (1985). Final report, July 1985-March 1986

P.R. Miles

Papers

Analysis and ranking of the acoustic disturbance potential of petroleum-industry activities and other sources of noise in the environment of marine mammals in Alaska. Final report

Prediction of drilling site-specific interaction of industrial acoustic stimuli and endangered whales: Beaufort Sea (1985). Final report, July 1985-March 1986