After months of silence, the song of a fin whale has once again been heard in the southern Ionian Sea, and was recorded by three different experiments connected to the submarine infrastructure of the INFN National Laboratories of the South (LNS-INFN), and conducted by the LNS and the Sicilian Centre for Nuclear Physics and the Structure of Matter (CSFNSM): ITINERIS, LOWNOISER and VONGOLA.
The detection took place at the end of the winter months, which were characterised by intense anthropogenic noise due to a prolonged geophysical survey campaign in the eastern Mediterranean aimed at the exploration of offshore hydrocarbon deposits, and only a few weeks after the passage of Hurricane Harry. The researchers succeeded not only in identifying the whale’s song, but also in tracking its movements in the area south-east of Sicily, thanks to the combination of traditional acoustic sensors and fibre-optic-based technologies.
The signals were indeed detected by the LNS acoustic sensors installed through the ITINERIS project (Italian Integrated Environmental Research Infrastructures System), led by the National Research Council (CNR) and dedicated to the development of an integrated network of infrastructures for the study of environmental processes. At the same time, the recording was confirmed by the Distributed Acoustic Sensing (DAS) systems installed for the first time in the Mediterranean as part of VONGOLA (Visual and nOise-eNhanced AI Analysis for Marine Biodiversity MonitorinG, Observation and LeArning), a National Recovery and Resilience Plan (PNRR) project coordinated by the CSFNSM to mitigate anthropogenic impacts on marine ecosystems, and subsequently by LOWNOISER, a Horizon Europe project dedicated to reducing acoustic pollution generated by maritime traffic.
“This is the first time that whale songs have been recorded simultaneously by such different measurement systems”, comments Giorgio Riccobene, researcher at the INFN National Laboratories of the South and INFN coordinator for the ITINERIS and LOWNOISER projects. “We used both the data from the piezoelectric hydrophones employed in ITINERIS and the new DAS technology used in the LOWNOISER and VONGOLA projects, which enables continuous monitoring of the soundscape”.
DAS technology represents one of the most advanced frontiers of marine acoustic monitoring. The system uses laser pulses transmitted along a submarine optical fibre to detect acoustic disturbances through analysis of the reflected light. In this way, the optical fibre is transformed into a chain of thousands of hydrophones distributed along the seabed, making it possible to monitor the marine soundscape in real time and distinguish between natural and anthropogenic sources.
Endangered population
“The detection of fin whale sounds is a result of great importance for this area, since the Mediterranean population is endangered and its presence in the Ionian Sea is still poorly documented. We know that the songs of these whales are used mainly for courtship and reproductive purposes, but we still know very little about how and in what context they are produced. Shipping noise is also a significant source of disturbance for this species and, thanks to this technology, we will be able to begin understanding better how maritime traffic interferes with fin whale vocalisations by assessing the degree of overlap between different acoustic signals”, comments Virginia Sciacca, CNR researcher and CNR coordinator for the LOWNOISER project.
“The possibility of having a distributed acoustic sensor extending for more than 100 kilometres allows us to detect the characteristic low-frequency calls of fin whales, around 20 Hz, and to track their movements across a very large area. We can therefore observe these great cetaceans across profoundly different marine environments, from coastal waters to the deeper areas of the Ionian Sea, helping to improve our knowledge of their distribution in a part of the Mediterranean where direct sightings remain relatively rare”, emphasises Salvatore Viola, INFN researcher and INFN co-coordinator of underwater acoustics activities within the ITINERIS and LOWNOISER projects.
The observation represents a new piece in a long tradition of research in which infrastructures developed for fundamental physics have also become valuable tools for marine sciences. For more than ten years, acoustic sensors installed on Sicilian submarine infrastructures, developed as a spin-off from the KM3NeT underwater neutrino telescope, have enabled the monitoring of the presence of cetaceans inhabiting the Ionian basin. Today, new dedicated technologies make it possible not only to detect cetaceans, but also to continuously monitor the noise produced by human activities and its impact on marine ecosystems.
“This result confirms the excellence of the acoustic sensor network on the Sicilian seabed and opens up new prospects for monitoring Mediterranean cetaceans”, comments Alessia Tricomi, director of the INFN Catania division, the CSFNSM, and coordinator of the VONGOLA project. “Thanks to the researchers at the CSFNSM and the LNS-INFN who are working to refine signal analysis algorithms, we will become increasingly accurate in recognising the presence of these great mammals and in assessing the effects of acoustic pollution on their communication, orientation and migration abilities”.
This new result once again demonstrates the value of multidisciplinary research and shows how the Ionian underwater observation network, built by INFN primarily for the KM3NeT telescope and fundamental neutrino physics research, can also become a permanent laboratory for the protection of marine biodiversity, capable of integrating physics, bioacoustics, artificial intelligence and environmental monitoring into a single system for listening to the sea.
ABOUT THE PROJECTS:
ITINERIS
The PNRR ITINERIS project coordinated 22 Research Infrastructures and integrated their data and services to create the Italian hub dedicated to the observation and study of environmental processes across the atmospheric, marine, biosphere and geosphere domains.
ITINERIS – Italian Integrated Environmental Research Infrastructures System – was a research project funded by the European Union – NextGenerationEU PNRR – Mission 4 “Education and Research” – Component 2: “From Research to Business” – Investment 3.1: “Fund for the creation of an integrated system of research and innovation infrastructures”.
LOWNOISER
The LOWNOISER project addresses the problem of underwater acoustic pollution caused by maritime traffic. The project partners, from both research and industry, will develop innovative noise reduction technologies, define regulatory standards and promote industrial practices for more sustainable maritime transport that is more respectful of marine ecosystems.
LOWNOISER is funded by the European Union’s Horizon Europe framework programme with €6.3 million.
VONGOLA
The VONGOLA project, funded under the PNRR, was dedicated to the development of innovative techniques for assessing and mitigating anthropogenic impacts on marine ecosystems, with particular attention to underwater acoustic pollution. Universities, research institutions and stakeholders collaborated on tools and technologies for the monitoring and protection of marine biodiversity in the Mediterranean Sea.
VONGOLA – Visual and nOise-eNhanced AI Analysis for Marine Biodiversity MonitorinG, Observation and LeArning – was a PNRR research project funded by the European Union – NextGenerationEU, within the National Biodiversity Future Center – Spoke 1, the scientific network leading national strategies for the monitoring, management and conservation of marine biodiversity.
To view the signal
To listen to the signal
This article is shared from LOWNOISER project partner National Institute for Nuclear Physics.