These autonomous buoys can detect a whale’s presence by listening to their calls. (Image Credit: Morgan Visalli/WHOI)
Yellow autonomous buoys from the Woods Hole Oceanographic Institute (WHOI) have been bobbling in ocean waters off the US East and West Coast to listen for nearby whales in real-time. A buoy detected a sei whale and a fin whale approximately twenty miles offshore Martha’s Vineyard. Scientists also think these robots could help ships maneuver around whales. WHOI marine ecologist Mark Baumgartner says wind energy companies, the US Navy, NOAA, state agencies, and Canadian researchers are working with these systems to reduce the risks of harming the whales. These buoys monitor whale activity on the West Coast as part of the Whale Safe system mapping ship and the large mammal movement.
The WHOI researchers deployed seven buoys and four Slocum gliders, each featuring the same software and instruments. The software, developed by Baumgartner, detects whale sounds and uses a spectrogram to generate pitch tracks. Then, the system compares these tracks to whale calls in an existing library. Audio clips containing whale sounds are transmitted to an onshore server. Analysts then listen to these sounds, determining whether or not the system detected whales. Afterward, they log the sound features along with the species producing them.
The Slocum gliders work with the buoys and send data back to the lab. (Image Credit: Paul Fucile/Woods Hole Oceanographic Institution)
Also, each glider and buoy features a computer, particle sensors that determine the sounds’ direction, and an underwater microphone. These computers transmit data to the lab via an iridium satellite system before being processed and posted on the Robots4Whales website. This data is also shared with the National Oceanographic and Atmospheric Administration.
While the buoy relies on year-lasting alkaline batteries for its power source, the glider uses a lithium-ion battery lasting for three to four months. WHOI specifically designed the buoy to stay quiet, allowing the instruments to pick up ocean sounds.
Each glider and buy has two-way communication capabilities. Every two hours, the glider sends its performance, location, and next destination data to a computer in the Woods Hole, Massachusetts lab. The researchers can move the system to another location or troubleshoot any onboard issues.
Planes, drones, or ships usually monitor the oceans to spot traveling whales, if not for this system. These techniques provide a visual reading of the whales, and captured images can be used to determine if they’re sick, injured, entangled, or dead. However, strong winds and other weather factors may affect flying instruments. Plus, imaging could present a problem if the ocean has a lot of white caps, making it more difficult to spot whales.
The researchers hope these robots use emails, texts, government software, an alert app, or other communication methods in the future to notify ships or fishermen of nearby whales.
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