Quiet time for orcas: noise reduction strategies that can assist orca in their foraging and communication

Presentation Abstract

Masking by underwater noise can decrease prey acquisition rates in southern resident killer whales (SRKWs) by impeding communication and echolocation during foraging. SRKW increase the source level of their vocalizations when broadband underwater noise increases (in correlation with the number of nearby boats), and ship noise extends to higher frequencies of SRKW echolocation. On San Juan Island, WA, along the Haro Strait we operate hydrophones for the long-term measurement of underwater noise and we record all the Automatic Identification System (AIS) reports from passing boats and ships. Since late July, 2017, the NEMES Program at the University of Victoria, has operated a HD camera from the site taking photos of Haro Strait every few seconds. With AIS data from ships and small boat data from the on-site camera, we have developed noise models parameterized with these local data. We evaluate noise reduction strategies using a suite of metrics (decibels weighted and unweighted, communication range, foraging range) and discuss how these strategies impact the percentage of time that SRKWs are exposed to various levels of underwater noise (peak, minima, and quantiles). Noise reduction strategies we assess include: ship source level reductions (e.g. hull cleaning, maintenance, speed limits); small boat speed limits and no-go zones; and vessel scheduling scenarios.

Session Title

Collaborating to Reduce Impacts of Underwater Noise from Vessels on SKRW: Biological Impacts of Underwater Noise from Vessels

Conference Track

SSE14: Vessel Traffic: Risks and Impacts

Conference Name

Salish Sea Ecosystem Conference (2018 : Seattle, Wash.)

Document Type

Event

SSEC Identifier

SSE14-555

Start Date

6-4-2018 9:45 AM

End Date

6-4-2018 10:00 AM

Type of Presentation

Oral

Genre/Form

conference proceedings; presentations (communicative events)

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Subjects – Topical (LCSH)

Killer whale--Haro Strait (B.C. and Wash.); Marine mammals--Effect of sound on--Haro Strait (B.C. and Wash.); Killer whale--Behavior--Haro Strait (B.C. and Wash.); Ship sounds--Research--Haro Strait (B.C. and Wash.)

Geographic Coverage

Haro Strait (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

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Apr 6th, 9:45 AM Apr 6th, 10:00 AM

Quiet time for orcas: noise reduction strategies that can assist orca in their foraging and communication

Masking by underwater noise can decrease prey acquisition rates in southern resident killer whales (SRKWs) by impeding communication and echolocation during foraging. SRKW increase the source level of their vocalizations when broadband underwater noise increases (in correlation with the number of nearby boats), and ship noise extends to higher frequencies of SRKW echolocation. On San Juan Island, WA, along the Haro Strait we operate hydrophones for the long-term measurement of underwater noise and we record all the Automatic Identification System (AIS) reports from passing boats and ships. Since late July, 2017, the NEMES Program at the University of Victoria, has operated a HD camera from the site taking photos of Haro Strait every few seconds. With AIS data from ships and small boat data from the on-site camera, we have developed noise models parameterized with these local data. We evaluate noise reduction strategies using a suite of metrics (decibels weighted and unweighted, communication range, foraging range) and discuss how these strategies impact the percentage of time that SRKWs are exposed to various levels of underwater noise (peak, minima, and quantiles). Noise reduction strategies we assess include: ship source level reductions (e.g. hull cleaning, maintenance, speed limits); small boat speed limits and no-go zones; and vessel scheduling scenarios.