This Micronesian Monday Feature is Part 2 of a report about a study of beaked whales around the Marianas. Read Part 1 here.

Since June, researchers have been collecting the sounds of the sea off the coast of Guam, hoping to better understand the beaked whale population around these parts. 

Holger Klinck, who is part of a team of folks taking on this project, said this study will help inform officials about the potential impacts of sonar on beaked whales. 

“For obvious reasons, the Marianas Islands are of high geopolitical importance. Hence, there is a large Navy contingency based on Guam that is required to train for readiness purposes regularly,” Klinck said. 

The Navy is required by law to minimize its impacts on marine mammals and get a permit from NOAA Fisheries for its operations, Klinck noted. He also pointed out that America is one of a few countries that has a law in place that protects marine mammals from harm. 

“Knowledge of local population sizes and trends thereof is important to assess the potential impacts of sonar use in the area,” he told The Husk. 

Acoustic recorders

Unlike other areas, there isn’t an extensive network of underwater acoustic sensors in the Marianas, Klinck said. 

“The Marianas Islands are challenging. Most other training areas in Hawaii, Southern California, Florida, and the Bahamas are equipped with extensive bottom-moored networks of underwater acoustic sensors,” he said. “These sensors allow real-time acoustic monitoring of marine mammals on the training ranges.”

With that in mind, researchers will use another way to monitor marine mammal populations here.

There will be six acoustic recorders used in this project. 

“Five of them will be deployed off the northwest corner of Guam,” Klinck said. These five recorders will be configured together to allow multiple recorders to pick up whale vocalizations. 

“This allows us to estimate where approximately the vocalizing whale—or group of whales— was located. Under ideal conditions, even in 3D!” Klinck said. “The sixth recorder will be deployed off the southwest corner of Guam. This data will give us an idea of how differently —or not— these locations are visited by beaked whales.”

Klinck said he expects to record a lot of marine mammal vocalizations. 

In 2014 and 2015, Klinck was part of a group that used autonomous underwater vehicles with acoustic sensors to survey offshore areas of mammals.

“During these surveys, we discovered a whale vocalization … that no one had recorded before, which was very exciting,” Klinck said of the 2014 and 2015 surveys. “A few years later, colleagues from NOAA were able to identify the source of these vocalizations: the Bryde's whale.”

Recording

From that experience, Klinck has an idea of what the recorders will pick up. 

“I am sure that we will record many marine mammal vocalizations,” he said. “While the primary focus is on beaked whales, we are interested in all species present in the area. Again, the project's focus is very specific … but I am also curious to see what has changed since we did the glider surveys several years back.” 

At the end of this year, the recorders will be retrieved and the data will be given to the U.S. Navy for review first. They want to ensure sensitive military signals aren’t contained in the data. After the data has been reviewed, then Klinck and the team will analyze the recordings for patterns of beaked whales. 

“This is a team effort. Our project partners are the University of St. Andrews in Scotland and Scientific Innovations, Inc., Philadelphia, PA. Cornell is in charge of collecting the acoustic data and analyzing it for occurrences of beaked whale vocalizations. Scientific Innovations, Inc. uses the outputs of our analysis to locate vocalizing individuals or groups of beaked whales in the vicinity of our hydrophone array,” Klinck said. 

Future research opportunities

This isn’t Klinck’s first time conducting research in this part of the world and he said he’s open to future research around Guam and Micronesia. 

There have been several large-scale marine protected areas established recently but Klinck said baseline data on the marine mammal species needed to manage these areas effectively is severely lacking. 

He noted that passive acoustics can help gather data of this type and he and his team are interested in aiding local communities in managing marine mammal populations. 

“Data on the abundance and distribution of most marine mammals in Micronesia, Melanesia, and Polynesia is still very sparse. There is so much we don't know,” he said. ◉

Read Part 1 of this report here:

The Husk

Beaked whales near Guam and potential sonar impact to be studied

This Micronesian Monday Feature is a multiple-part report about a study of beaked whales around the Marianas…

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6 days ago · 5 likes · 1 comment · Jasmine Stole Weiss