Only 400 North Atlantic right whales are left in the wild today, and only 100 of these whales are breeding females. Boat strikes and being entangled in fishing gear are their greatest survival threats. These whales can be protected by diverting boats away from potentially dangerous encounters. New technology described in the Journal of the Acoustical Society of America could make this possible.
Researchers often use underwater microphones, called hydrophones, to listen for marine life. These mics are mounted on robotic gliders or buoys. The audio recorded is converted into spectrograms, visual representations of sound that can be used to identify specific whale species calls. These distinctive sounds can often be drowned out with background noise. Researchers have been using deep learning, a machine-learning technique that automates this analysis in recent years. However background noises still hamper reliability.
Researchers have now trained two deep learning models to help cut through the noise. The models were first given thousands of clean spectrograms containing only North Atlantic right whale sounds. They then slowly added thousands of spectrograms with background sounds such as tanker engine hums. Scientists say the algorithms are capable of turning noisy spectrograms into clean ones. This reduces false alarms and helps spot whales before they reach danger zones.
Shyam Madhusudhana is a Cornell University data engineering engineer who was not part of the study. He says that he would like to see if these models could also be used to locate marine mammals. He notes that dolphins and humpback whales have more complex speech paths than right whales. Ben Milner, a University of East Anglia machine learning researcher, is one of the authors of the study. He hopes to use this technology to detect animals in the Ukrainian forests where he was able to locate them near the Chernobyl disaster of 1986.
Peter Tyack, University of St. Andrews behavioral ecologist, said that the new system can be used to determine where whales are in the year so that they can be protected. Tyack believes this technology is a great tool for estimating the density or abundance of these whales in areas where they are difficult to see.
However, he cautions that this should not be the only way to prevent ship strikes and entanglement. Tyack's research has shown that North Atlantic right whales are able to be quiet for hours at times. Passive acoustic monitoring might miss one. Tyack says that killing just one of these whales could result in the extinction of the entire population.
