Dear MARMAM,

My colleagues and I are pleased to announce the open access publication of the following paper in The Journal of Ocean Technology, available here <https://www.thejot.net/article-preview/?show_article_preview=1091>:

Wladichuk, J.L., D.E. Hannay, A.O. MacGillivray, Z. Li, and S. Thornton. 2019. Systematic Source Level Measurements of Whale Watching Vessels and Other Small Boats. Journal of Ocean Technology 14(3): 108-126.

*Abstract*
Marine mammals rely heavily on sound for foraging, communicating, and navigating. As noise in the ocean increases, their ability to perform these important life functions can be affected. Improving our knowledge of how sound impacts marine mammals is particularly important in coastal waters where the spatial distributions of vessels and marine mammals overlap, as exemplified by the critical habitat for the endangered Southern Resident killer whale (SKRW). The impacts of small vessel traffic (including the commercial and recreational whale watching that is directed on this population) has been difficult to assess as there is a data gap for small vessel noise emissions. In this study, two autonomous marine acoustic recorders were deployed in transboundary Haro Strait (British Columbia, Canada, and Washington State, USA) from July to October 2017 to measure sound levels produced by whale watching vessels and other small boats. During this period, 20 different volunteer vessels were assessed operating at a range of speeds – nominally 5 knots, 9 knots, and cruising speed (generally 20-30 knots) to represent whale watching, approach, and transit speeds, respectively. This paper presents source levels with speed in frequency bands which have specific application to SRKW. In general, landing crafts produced the highest source levels (overall mean = 166 ± 5 dB re 1 μPa m), followed by catamarans (160 ± 10 dB re 1 μPa m), RHIBs (158 ± 11 dB re 1 μPa m), monohulls (157 ± 12 dB re 1 μPa m), sailboats (153 ± 9 dB re 1 μPa m), and the small vessel with a 9.9 HP outboard engine was the quietest across speeds and frequency bands measured (150 ± 10 dB re 1 μPa m). Most vessel types demonstrated a higher rate of increase in source level with speed in the higher frequency band, representative of their echolocation range. Analysis also compared spectral levels between different propulsion types.

Feel free to contact me (Jennifer.wladichuk@jasco.com) if you'd like a copy of the high-resolution PDF.

Kind regards,
Jen Wladichuk

Jennifer Wladichuk, Ph.D.

Project Scientist

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