What did we hear?

Click the icons in the scene below to listen and learn about the sounds we recorded in this sanctuary.


Where did we listen?

Here is a map of listening device locations. Hover on a location to see its site id and click on it to see the rationale for its placement.

The listening range of a hydrophone is influenced by its location and seasonal changes in ocean conditions, and it is specific to a source of sound (intensity, frequency, placement in the water column). The peach shading in this map estimates the listening range on the north side of Santa Rosa Island in Channel Islands sanctuary during April for a 165 decibel and 300 Hertz sound source placed 1 meter below the surface.
There were five SanctSound listening sites in Channel Islands sanctuary. Green bars indicate when good quality data were recorded. Due to logistical or technical difficulties, there were gaps in recordings (white) or periods with compromised data quality (yellow).

Learn more about how we listened to and recorded soundscapes.
See similar maps of the listening range for the other hydrophones in this and in other sanctuaries.

What did we measure?

Spectrogram: intensity of sound at different pitches over time

This example spectrogram from a listening station off north Santa Rosa Island in Channel Islands sanctuary shows that sound levels were louder (warmer colors) at medium pitches and quieter (cooler colors) at lower and much higher pitches, reflecting contributions of snapping shrimp and fish to this biologically driven soundscape. Information about the quality of the sound data is included along the bottom of the plot with green indicating time periods of good quality data, yellow indicating periods with compromised data, and data gaps shown with white. In the data portal, you can get more information about what frequencies of data are compromised during a time period by hovering over each yellow color bar.

Sound levels above median: loudness and contribution of different pitches

This histogram of above-median sound levels for the north Santa Rosa listening station in Channel Islands sanctuary shows inter-annual variability in the soundscape, with the summer of 2020 having the highest overall sound intensity and a notable drop in levels fall 2020 through fall 2021. Data quality is shown in color as described above.

Power spectrum: variability of loudness across pitch

This power spectrum plot for the north Santa Rosa listening site in Channel Islands sanctuary shows that medium pitched sounds (1,250-20,000 Hertz) had the highest median intensities (black line) and were consistently louder throughout the study period (narrow gray band). Sounds with frequencies below 1,250 Hertz were generally quieter (black line), but also were more variable over time (wider gray band).

Anomaly plot: deviation of loudness from average

This sound levels anomaly plot for the north Santa Rosa listening site in Channel Islands sanctuary shows the same inter-annual variation seen in the histogram but more clearly identifies the pitches of sound that were higher than the median. Low to mid frequencies (0-1,250 Hertz, shades of red) were higher in 2018, 2019 and 2021, while high frequences (>1,250 Hertz, shades of red) were higher in 2020. Data quality is shown in color as described above.

Learn more about what we measured and how to read and understand these summary graphs.

See similar summary graphs for the other stations in this sanctuary and here for data available in other sanctuaries.

What did we learn?

One Fish, Two Fish

Learn about our collection of stories.

Read more SanctSound stories.