Underwater noise and cetaceans in British Columbia and Washington State

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Underwater noise and cetaceans in British Columbia and Washington State

Its been a busy year for the SMRU Consulting North America team. But, we are ending the year on a high with the publication of two recent reports and the preliminary results of the Vancouver Fraser Port Authority’s vessel Slowdown trial.

The preliminary results of the Slowdown trial and our reports on the effects of noise on Southern Resident killer whales from whale watch boats and commercial shipping, and humpback whale calling behavior in the presence of shipping were released in the Vancouver Fraser Port Authority’s ECHO program newsletter on Friday 15 December.

The reports are available here:

Voluntary vessel slowdown trial in Haro Strait: Preliminary results

Estimating the effects of noise from commercial vessels and whale watch boats on Southern Resident killer whales

Effects of ship noise on calling rates of humpback whales in British Columbia

 

Voluntary vessel slowdown trial in Haro StraitHaro Strait vessel slow down infographic

The Slowdown trial took place from August 7 to October 6 this year and was the first trial that asked ocean-going ships to slow down for the purpose of reducing underwater noise levels. The goal of the trial was to explore how reduced ship speed changes underwater noise levels in the critical habitat of the endangered Southern Resident killer whale (SRKW).  While there are regulations in place to slow vessels in other parts of the world these have all been implemented to reduce the risk of ships colliding with whales and not to reduce ship noise in the marine environment.

While we are busy working with the ECHO program to analyze the results of the Slowdown trial (available in late January 2018) the preliminary results are now available. Our efforts have included continuous monitoring of ambient underwater noise at our Lime Kiln hydrophone off San Juan Island in Washington State -an important foraging area for the SRKW. Preliminary results suggest that there was a ~12% reduction in sound intensity at Lime Kiln during the trial period. Further fine-scale analyses of these data are ongoing.

 

Effects of whale watch and commercial shipping noise on Southern Resident killer whales

Southern Resident killer whales are also the primary target of a thriving cross-boundary whale watching industry in British Columbia and Northern Washington State. During the spring, summer, and fall killer whales find themselves in the proximity of small vessels for much of the day, compared to the transiting ocean-going vessels. This difference in time and, also different sound signatures of smaller whale-watch boats may also affect SRKW.  Our study used a computer modeling approach to compare the behavioral responses of SRKW to large commercial ocean- going vessels and the noise generated by whale watching boats.

noise from whale watch boats and commercial vessels in combination may result in a cumulative loss of time for foraging representing 20% to 23% (4.9-5.5 hours) of each day that SRKW are present in the study area during May to September.

Potential effects of ship noise on humpback whale calling rates in BC waters

In 2016 we collaborated with Oceans Initiative to investigate the potential effects of shipping noise on humpback whale calls in British Columbia coastal waters. Humpback whales have seen a significant resurgence in coastal BC coastal waters over the last few years as populations in the Pacific have recovered from the effects of commercial whaling.  With increasing numbers of whales using coastal waters there is a greater potential for interactions with vessels. Ship noise has been identified as a concern by Fisheries and Oceans Canada (DFO) because of the potential for ship noise to mask calls and interfere with the whales’ behavior.  Our study indicated that that the noise from ships may be influencing humpback whale calling behavior but much more work is required to better understand the humpback whale calling behavior in British Columbia.

A humpback whale known as “Heather” swims past San Juan Island in October 2017. Photograph by Alison Engle.

 

An uncatalogued Pacific humpback whale displays it’s flukes off the South end of Lopez Island in the Salish Sea. Photograph by Alison Engle.

Check out these previous blog posts to learn more about each of these projects:

About the Author:

Frances is a Research Scientist at SMRU Consulting North America. Check out her bio under the "About Us" tab.

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