| "Some people talk to animals. Not many listen though. That's the problem."
Four Sanctuaries Soundscape Monitoring
Together with the Office of National Marine Sanctuaries, ongoing acoustic research is examining the soundscapes of four relatively shallow U.S. National Marine Sanctuaries on the east coast and in the Gulf of Mexico. Since 2016, hydrophone recorders, (SoundTraps developed by Ocean Instruments) have been seasonally deployed in two sites of interest in Stellwagen Bank, Grays Reef, Florida Keys, and Flower Gardens National Marine Sanctuaries.
The acoustic information gathered will be used to classify the acoustic signatures of each of the eight sites, including relative contributions from human produced noise sources, as well as marine wildlife (invertebrates, fish and mammals) and geophysical sources (wind, waves).
We aim to continue this sampling during all four seasons of the year and use this data to contribute to a more complex status assessment regarding current ecological soundscapes within these sanctuaries. Ultimately, the long term goals of this project are to gain information on soniferous species presence/absence, daily/lunar/seasonal patterns in chorusing, anthropogenic noise inputs, and possibly cetacean movement. We will also use this data to aid in the development of novel acoustic metrics and test these against more traditional metrics.
To date, the two sites at Gray's Reef sanctuary have been found to be the most acoustically diverse of the four sanctuaries. There were significant daily patterns in sound pressure levels (broadband, 63 Hz and 125 Hz) due to the acoustic activity of abiotic (tidal currents at new and full moon phases) and biotic factors. In the recordings, there is an enormous diversity of fish and invertebrate acoustic signals. Anthropogenic sound is also distinguishable and is likely due to heavy research vessel activity at the site. Vessel signal is the largest contributor towards changes in the sound pressure levels.
In contrast, Stellwagen Bank sanctuary has had a very different acoustic signature to that of Gray's Reef. The recordings were dominated by low frequency signal of large vessels. There was a broadband sound pressure increase around midday during all moon phases, due to an increase in the number of vessels not only in the immediate vicinity of the hydrophones, but also at greater distances. The identified acoustic telemetry tags that were detected in this Sanctuary were from great white sharks, Atlantic cod, haddock, Atlantic sturgeon, American shad, Atlantic Bluefin tuna, and striped bass.
To learn more about the Four Sanctuaries Monitoring Project, please watch this video or visit the Office of National Marine Sanctuaries web site.