Data visualizations illustrating the impact of ocean noise on Southern resident killer whale foraging
Presented here are select animations of vessel distributions around focal whales which depict how the echolocation space responds to the dynamic vessel noise field.
We used custom bioacoustic software, best-available estimates of vessel source levels, and whale and vessel tracks from 2003-05 and 2020 to develop realistic animations of SRKW sound exposure. The noise model results are presented in a plan-view perspective of a killer whale swimming through a distribution of vessels. The whale and boat tracks are based on spatial field data collected by Oceans Initiative. The killer whale that was observed through a focal follow is represented by a to-scale icon (black & white orca).
Notes for viewing these animations:
- The title above the animation frame shows date-time, track ID, number of boats (total and audible/moving), and the focal whale ID.
- A metric scale bar is provided, no matter what “zoom” level is selected.
- The blue ellipses that move with the whale represent the maximum and current active echolocation space — the regions in which the whale could detect an adult Chinook salmon in natural background noise and the current level of boat noise, respectively. As the whale receives higher levels of boat noise, the inner, darker-blue ellipse shrinks — indicating a reduction in foraging space and efficiency.
- Each vessel is depicted by a label overlying circular zones of varying colors that indicate the level of radiated noise.
- Purple (<110 dB (re 1uPa));
- Yellow (110-120 dB (re 1uPA));
- Green (120-130 dB (re 1uPA));
- Red represent high noise levels (>130 dB (re 1uPA)).
Ships Going Fast vs. Slow — 2020
Animation of SRKW sound exposure in the presence of close approaching boats and a slow passing ship on July 7, 2020. The northbound ship presents a large acoustic footprint, however the greatest noise is demonstrated by the close approaching research boat. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (J pod, male).
Ships and Boats Present — 2020
Animation of SRKW sound exposure in the presence of ships, commercial whale watching boats, and recreational boats on September 1, 2020. Ships show a noisier footprint until commercial and recreational whale watching boats increase speed and their acoustic footprints expand dramatically. The presence of ship noise indicated by the large red zone results in the shrinking of the whale’s echolocation space. There are also several other vessels present, including two private boats, which appear to affect the whale’s echolocation space variably until finally, the whale moves away. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (J pod, juvenile).
Boats Going Fast vs. Slow — 2003-05 and 2020
Animation of SRKW sound exposure in the presence of three boats transiting the area on August 21, 2003. The whale’s echolocation space shrinks when a faster moving vessel passes the area quickly. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (L74, L pod, male).
Animation of SRKW sound exposure in the presence of 13 boats (11 private, 1 commercial whale watch, and 1 enforcement vessel) transiting the area on July 6, 2020. The whale’s echolocation space is reduced when multiple private vessels pass the whale at a higher speed. A commercial whale watch vessel remains unmoving towards the bottom right of the screen. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (J pod, male).
Boats Close to Whales vs. Boats Far from Whales — 2003-05 and 2020
Animation of SRKW sound exposure in the presence of boats close and far away on July 4, 2004. The whale’s echolocation space is limited as boats continue to follow the whale at a close distance. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (unidentified).
Animation of SRKW sound exposure in the presence of boats close and far away on September 1, 2020. Traveling boats far away reduces the whale’s echolocation space and grows when passing through close stationary boats. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (J51, J pod, male).
Boats Following Whale-watch Guidelines vs. Boats Not Following Guidelines
Animation of SRKW sound exposure in the presence of multiple commercial whale-watch vessels on September 6, 2003. The whale’s echolocation space dramatically reduces as four whale watching boats travel through the whale’s path, and grows when moving past two stationary whale watching vessels. The whale changes direction as a single whale watching vessel travels perpendicular to the whale. Another boat in particular speeds through and causes the active echolocation space to disappear. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (unidentified).
Animation of SRKW sound exposure in the presence of multiple vessels, including commercial whale watches, on September 1, 2020. The whale changes direction when approached by 3 commercial whale watch vessels, and its echolocation space is reduced. One commercial whale watch vessel towards the top right of the frame maintains its position while all others continue to follow the whale at a closer distance. This is presented in a plan-view perspective of a to-scale focal killer whale icon swimming (J51, J pod, juvenile male).