What is the purpose of hydrophones, and how was the location of release decided?

• We were initially funded by NOAA to help detect endangered Southern Resident killer whales (SRKW) acoustically. During foggy days or at night when the local sighting networks are inoperable, the acoustic detections helped NOAA/NMFS and other researchers rapidly respond to acquire prey and fecal samples to inform studies of SRKW diet and endocrinology. Locations were distributed across the known and likely critical habitat of the SRKWs.

What are the pros of using passive acoustic monitoring (PAM)?

• For soniferous species, PAM works at night and when daytime visibility or sea state impede visual observations.

What are some of the cons?

• If the hydrophone is not accessible in real-time, the acoustic detections are usually not available for days to weeks, so dynamic management isn't possible.

• Hydrophones and hydrophone networks are still expensive, with sensors costing $300-$3,500 each and cable costing $1-3 per meter.

What are some positive encounters you have witnessed with the public using your website?

• With listeners from around the world, a benefit of the Orcasound web app at live.orcasound.net is engagement in conservation actions for the whales and learning about orcas and bioacoustics.

What are ways in which acoustic monitoring is beneficial to educate the public on the challenges that marine mammals face?

• If you listen to the live audio stream for a few hours, even if you don't hear whales, you'll hear the dominant sources of noise in their habitat: commercial ships and recreational powerboats. Increasing public awareness of these sources of noise pollution can lead to mitigation that helps orcas communicate and hunt more efficiently in the urban areas near Seattle.