Impacts of underwater noise on orcas

Scott Veirs, Orcasound hydrophone network

Clallam MRC Orca Forum
May 10, 2019, Port Angeles

Slides at: orcasound.net/talks

Zones of bioacoustic impact from noise

  1. Injury (acoustic trauma, or stranding)
  2. Deafening (permanent or temporary threshold shift)
  3. Behavioral change (can also be due to physical proximity or interference)
  4. Masking of signals and cues
  5. Stress (e.g. from chronic noise)
  6. Audibility

Potential impacts of noise on southern resident killer whales (SRKWs)

  1. Injury (L112? J34?)
  2. Stranding (observed in other toothed whales, but not SRKWs)
  3. Deafening (permanent or temporary)
    • What explosives were used near SRKWs during the capture era, and previously?
    • Pile driving?
    • MFA sonar: (HMS Ottawa, 2012)
    • Naval detonations: (HMS Ottawa, 2012)
  4. Behavioral change (can also be due to physical proximity or interference)
  5. Masking of signals and cues (mostly by vessels)
  6. Stress (e.g. from chronic noise)
Right whale stress fell after 9/11 decreased ship noise in 2001 (Rolland et al., 2012)

We know: SRKWs respond to noise

2003: U.S. Navy uses sonar in Haro Strait with SRKW behavior change observed by Center for Whale Research

2009: SRKWs "speak up" in noise from nearby boats (Holt, Noren, Veirs, Emmons & Veirs)

Vessel noise can mask both calls & clicks

Frequencies of vessel noise overlap
with SRKW hearing and signals

Veirs, Veirs, & Wood (2016, PeerJ)

Typical ship:

Squeaky ship:

Vessel noise can mask both calls & clicks

It's already too loud!

  1. Communication space reduced: 75% for NRKWs (Miller+2006); 94-98% for SRKW by Haro ships (Veirs+2011)
  2. Current levels of Salish Sea noise caused 62-97% loss of communication space (Williams et al., 2014)
  3. Foraging space reduced 58-89% by Haro ships (Veirs+2011)
  4. 85% decrease in echolocation range in container ship noise at 440 meters (Holt, 2008)

We also know:

  1. Ships dominate the Haro Strait soundscape
  2. Ships transit Haro Strait ~20 times/day
  3. Boats elevate mean ambient noise levels ~2 dB during summer

Vessel noise mitigation

There are many ways to "more than mitigate" vessel noise.

Operational (temporary) and technological (permanent)

Orcasound's network, new nodes and app

15 years of citizen scientists listening for whales in the Salish Sea

Thanks to all the backers of the 2017 Kickstarter, plus our app key developers/designers to date:
Paul Cretu, Skander Mzali, Steve Hicks, Tyler Crisafulli, Nóra Mészáros, and Liam Reese

Listen for whales at live.orcasound.net!

Listen for whales

For free live-listening, browse to:
live.orcasound.net

New player was released to the public on November 1. Stay tuned for more features coming this summer at: beta.orcasound.net

Questions?

Maximizing near-term SRKW acquisition of Chinook salmon

Supply

Long-term:
  1. Habitat
  2. Hydropower
  3. Hatcheries
  4. Heat
Short-term:
  1. Harvest! Commercial; recreational; tribal; Canadian; Alaskan; N Pacific!?
  2. ...

Access

  1. Decrease masking of echolocation (minimize cavitation [and echosounders?] in all vessels)
  2. Decrease masking of communication calls during foraging
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