@article {57996,
	title = {High-amplitude vocalizations of male northern elephant seals and associated ambient noise on a breeding rookery},
	year = {2019},
	abstract = {<p>Northern elephant seals (Mirounga angustirostris) are massive, land-breeding marine mammals that produce loud, stereotyped calls during annual breeding seasons. To determine vocalization source levels emitted by competing males on a mainland breeding rookery, aerial calls were measured on-axis at 1\&thinsp;m from adult males using three different sound pressure level metrics. Time-averaged (1 min) ambient noise was also measured under variable environmental and social conditions. Results indicate that male northern elephant seals emit high amplitude airborne calls with little variation in call amplitude. Mean source levels ranged from 98 to 114\&thinsp;dB re: 20 \&mu;Pa [root-mean-square (rms) -fast], 102\&ndash;116\&thinsp;dB re: 20 \&mu;Pa (rms-impulse), and 120\&ndash;131\&thinsp;dB re: 20 \&mu;Pa (peak) and average standard deviations for all metrics were \&lt;2.3\&thinsp;dB. Further, these seal rookeries exhibit high variability in ambient noise (in terms of both spectrum and amplitude) from biotic and environmental sources. Finally, males sampled did not adjust call amplitude to compensate for higher background noise levels and thus did not exhibit a Lombard effect. These findings reinforce the view that the remarkable vocalizations of male northern elephant seals serve as rigid and powerful signals that convey individual identity within noisy breeding colonies rather than as honest indicators of size, status, or motivation.</p>
},
	doi = {10.1121/1.5139422},
	url = {http://asa.scitation.org/doi/10.1121/1.5139422},
	author = {Southall, Brandon L. and Casey, Caroline and Marla M. Holt and Stephen J. Insley and Reichmuth, Colleen}
}
@article {53305,
	title = {Assessing vessel slowdown as an option for reducing acoustic masking for Arctic cod in the western Canadian Arctic},
	journal = {The Journal of the Acoustical Society of America},
	volume = {144},
	year = {2018},
	month = {Jan-09-2018},
	pages = {1662 - 1662},
	abstract = {<p>Noise from this shipping traffic can lead to acoustic masking, reducing the ability of marine animals to detect and use biologically important sounds. Vessel-slow down may be an alternative mitigation option in regions where re-routing shipping corridors to avoid important habitat for fish and marine mammals is not possible. We investigated the potential relief in masking from a 10 knot speed reduction of container and cruise ships. Based on ambient sound measurements and real shipping data, the percentage reduction in the available listening space for fish as a container or cruise ship passes under varying speeds and ambient sound conditions was shown. The mitigation effects from slower vessels (travelling at 15 knots compared to 25 knots), in terms of auditory masking, was equal between ambient sound conditions, but not equal between the type of vessel. Slowing vessels led to a substantial decrease in the listening space reductions, with the amount of reduction varying by distance away from vessels. Vessel slowdown through sensitive habitat could be an effective mitigation strategy for reducing the extent of auditory masking.</p>
},
	issn = {0001-4966},
	doi = {10.1121/1.5067412},
	url = {http://asa.scitation.org/doi/10.1121/1.5067412},
	author = {Pine, Matthew and Hannay, David E. and Stephen J. Insley and William D. Halliday and Juanes, Francis}
}
