Understanding and managing underwater noise: results from the Haro Strait vessel slowdown trial

The Enhancing Cetacean Habitat and Observation (ECHO) Program is a Vancouver Fraser Port Authority-led initiative aimed at better understanding and managing the impact of shipping activities on at-risk whales throughout the southern coast of BC. Between August 7 and October 6, 2017, the ECHO Program managed a voluntary vessel slowdown trial in Haro Strait, located between Vancouver Island in British Columbia and San Juan Island in Washington State. Haro Strait is an important summer feeding area for southern resident killer whales, and a busy international shipping route. Through extensive consultation and collaboration with the Pacific Pilotage Authority, BC Coast Pilots, regional shipping associations and agents, as well as international vessel owners and operators, the overall reported participation rate for piloted commercial vessels at the conclusion of the trial was over 60%. Temporary, deep-water listening stations in the shipping lanes of Haro Strait, a shallow hydrophone off Lime Kiln State Park, and the long-term listening station in the Strait of Georgia were all used to collect data on underwater noise during the trial. Due to the excellent vessel participation rates, the ECHO program team and our consultants at JASCO Applied Sciences and SMRU Consulting were able to obtain a robust data set to evaluate: how reduced speed changes the underwater noise (source level) generated by specific vessels and by vessel classes; how reduced vessel speed changes the total ambient noise; and how these changes in noise may impact the killer whale. The trial results will help the ECHO Program and the Government of Canada make informed decisions on how to reduce the impact of vessel noise on endangered whales. These learnings will be of interest globally to those looking to manage vessel noise in sensitive whale habitats

Commercial ship versus whale watch boat noise: relative effects on Southern Resident killer whales

Underwater noise may be impacting the population recovery of critically endangered Southern Resident Killer Whales (SRKW). This study used an SRKW-Noise exposure simulation model to compare noise effects from large (AIS-enabled) commercial vessels with whale watch boats during summer (May-September) within their principal Salish Sea habitat range use. It predicted moderate or low behavioural responses (BRs) using SRKW-specific dose-response relationships and, if no BRs were triggered, the extent of residual high frequency echolocation click masking. BRs were considered to result in lost foraging due to switches in behaviour or via strong masking effects. The Monte-Carlo simulation used a fine-scale acoustic model to predict broadband sound pressure levels (SPL, BR analysis) and power spectral density (PSD) at 50 kHz (click masking analysis) for AIS-enabled commercial vessels. To derive equivalent data from whale watch boats, we combined data from Holt et al. (2009), SoundWatch and Beam Reach Sustainable School. SRKW habitat used a 10-year synthesis of effort-correct observer sightings. Overall, noise from AIS-enabled vessels was estimated to contribute 93% of overall BR-related potential lost foraging time, with whale watch boats contributing the remaining 7%, despite mean estimates of 6.1hr of boats with each whale per day. Lower SPLs of slow moving boats had low probabilities of exceeding BR thresholds, while large commercial vessel often exceed these thresholds. Lost foraging time per whale was estimated as a median 3.2hr per day when whales were present (13.4% of day). Echolocation click masking effects accumulated an additional 1.7hr of lost foraging time and was strongly dominated by noise predicted from slow (2.5-8 knot) whale watch boats, noting high model uncertainty due to PSD, speed and proximity assumptions. Overall, lost foraging time totaled 20.3% of each whale day (4.9hr), with ~2/3 due to AIS-enabled commercial vessels, highlighting mitigation measures for both vessel types should be considered

Potential Benefits of Vessel Slowdowns on Endangered Southern Resident Killer Whales

A voluntary commercial vessel slowdown trial was conducted through 16 nm of shipping lanes overlapping critical habitat of at-risk southern resident killer whales (SRKW) in the Salish Sea. From August 7 to October 6, 2017, the trial requested piloted vessels to slow to 11 knots speed-through-water. Analysis of AIS vessel tracking data showed that 350 of 951 (37%) piloted transits achieved this target speed, 421 of 951 (44%) transits achieved speeds within one knot of this target (i.e., ≤12 knots), and 55% achieved speeds ≤ 13 knots. Slowdown results were compared to ‘Baseline’ noise of the same region, matched across lunar months. A local hydrophone listening station in Lime Kiln State Park, 2.3 km from the shipping lane, recorded 1.2 dB reductions in median broadband noise (10–100,000 Hz, rms) compared to the Baseline period, despite longer transit. The median reduction was 2.5 dB when filtering only for periods when commercial vessels were within 6 km radius of Lime Kiln. The reductions were highest in the 1st decade band (-3.1 dB, 10–100 Hz) and lowest in the 4th decade band (-0.3 dB reduction, 10–100 kHz). A regional vessel noise model predicted noise for a range of traffic volume and vessel speed scenarios for a 1133 km2 ‘Slowdown region’ containing the 16 nm of shipping lanes. A temporally and spatially explicit simulation model evaluated the changes in traffic volume and speed on SRKW in their foraging habitat within this Slowdown region. The model tracked the number and magnitude of noise-exposure events that impacted each of 78 (simulated) SRKW across different traffic scenarios. These disturbance metrics were simplified to a cumulative effect termed ‘potential lost foraging time’ that corresponded to the sum of disturbance events described by assumptions of time that whales could not forage due to noise disturbance. The model predicted that the voluntary Slowdown trial achieved 22% reduction in ‘potential lost foraging time’ for SRKW, with 40% reductions under 100% 11-knot participation. Slower vessel speeds reduced underwater noise in the Slowdown area despite longer passage times and therefore suggest this is an effective way to benefit SRKW habitat function in the vicinity of shipping lanes

Transboundary Programs to Quiet the Seas: Successes, Challenges, and the Road Ahead

Of all the threats facing the southern residents, reducing noise and disturbance is one area where we have made tangible progress around the Salish Sea. Public processes have led to new programs and policies - successes we can build on, and learn from. This panel will provide a transboundary perspective on programs that been implemented to manage and monitor vessel impacts by sector (i.e., large ships, small vessels), and identify high priority gaps or needs. For each program, panelists will discuss: 1.) What are the successes, so far? What are the challenges, and where are the gaps? 2.) How does your program measure its effectiveness? How will it adapt to new science and and emerging threats? 3.) What is the biggest gap or area of need for transboundary alignment and how would you propose to address it

The Enhancing Cetacean Habitat and Observation (ECHO) Program: collaborating to manage potential cumulative threats to at-risk whales from commercial vessels

The Enhancing Cetacean Habitat and Observation (ECHO) program is a Port Metro Vancouver led collaborative initiative aimed at better understanding and managing the cumulative impact of commercial vessel activities on at-risk whales throughout the southern coast of British Columbia. Some of the key threats to whales in this region include: acoustic disturbance (underwater noise), physical disturbance (ship collisions), environmental contaminants, and the availability of prey. With the benefit of early input and advice from both Canadian and US scientists, shipping and marine transportation industries, conservation and environmental groups, First Nations individuals and government agencies, the ECHO Program is advancing a series of individual short-term projects, scientific studies and educational initiatives to achieve the Program’s long-term goal of developing mitigation and management options that will lead to a quantifiable reduction in vessel-related threats to whales. This presentation will introduce some of the initiatives and projects that are being advanced by the ECHO Program and will describe how the Program is bringing relevant interests together to explore innovative ways to better understand and manage regional cumulative impacts from commercial vessel activities. A number of ECHO-related projects, and work being conducted by our partners and advisors will be further highlighted in associated presentations within this session. Such presentations may include: JASCO’s development of a regional cumulative noise model; ONC and JASCO’s development of hardware for a marine acoustic system in the shipping lane and automated detection, classification, ship source level and ambient noise reporting software; BC and Washington State Ferries cross-border collaborative approach to managing impacts to whales; Vancouver Aquarium’s development of a Mariners guide to whales for the West Coast; DFO and Ocean Sonics Whale tracking Network; NOAA’s work on measurement of contaminant levels in SRKW and, DFO’s assessment of lethal vessel strike risk to whales off west coast of Vancouver Island