One of the world’s most endangered whale species could get help from threats posed by humans, through technology developed by the University of East Anglia (UEA). Researchers have developed machine learning techniques that can be used to detect North Atlantic right whales by listening for the sounds they make underwater.
Finding the animals before they get close to ships can both protect the whales and avoid costly shutdowns of offshore operations.
North Atlantic right whales are one of the world’s most endangered marine species with only around 350 remaining and of those, only about 100 females of breeding age. Human activities are a significant threat to right whale populations, either through entanglement in fishing gear or strikes from shipping.
Calls from right whales are often confused with noises made from shipping or other underwater activities, such as fishing and drilling. The new techniques can remove these unwanted noises from recordings, thereby increasing the reliability of detecting right whales in adverse conditions.
The conventional way of locating right whales relies on observers onboard ships, but this is expensive and not possible at night or in low-visibility conditions. An automated method to detect the presence of right whales gives much more hope for the species to survive and increase in population, said lead researcher Dr Ben Milner of UEA’s School of Computing Sciences.
Dr Milner, a senior lecturer, said: “The aim of this work is to develop robust methods of detecting marine mammals from passive acoustic monitoring (PAM) devices in challenging environments.
“Having the ability to deploy an automated system – whether it be on buoys, Autonomous Surface Vehicles (ASVs), or gliders – that can achieve high levels of detection in real-time, is vital to the long-term future of right whales.
“Being able to reliably detect marine mammals is important for population monitoring and for mitigation, as many species are endangered and protected by environmental laws.”
Right whales emit a range of vocalisations, with common sounds being upcall tones and gunshot sounds. Upcalls most likely play a role as a social contact call between individuals and are produced by both sexes and different age classes, and are therefore most commonly used for passive acoustic detection of the species. The gunshot sounds are very different from upcalls and are characterised as an impulse, and although less common, can also be detected by the new technology.
Both vocalisation types can be difficult to hear in noisy conditions and to visualise in spectrograms, as low frequency regions are often masked by marine noise from passing ships, drilling and piling activities, seismic exploration, or interference from other marine mammals, such as humpback whale song. In many cases, anthropogenic and environmental noises overlap in frequency with right whale calls, which makes detection difficult.
The researchers studied ‘de-noising’ processes that could block out non-whale noises from trawlers, tankers and other human activities.
Photo credit: NOAA News