22 MAR 2018

Olivier Adam is a professor at the Jean-Rond d'Alembert Institute (at Sorbonne University/CNRS), in the Lutheries-Acoustique-Musique (LAM) team. As a specialist in bioacoustics, he works on cetacean sound emissions, in order to study their behavior, their habitats, and their movements.

For International Whale and Marine Mammal Day on February 19, 2018, he talks about the threats to these giants of the seas and the research interest in their preservation.

Olivier Adam
Olivier Adam

What are the main threats to whales?

All 89 cetacean species are on the International Union for Conservation of Nature's Red List. This sad situation is a direct consequence of the massive industrial hunt practiced in the 20th century. Today, despite the international moratorium on hunting and the creation and development of marine sanctuaries, some countries continue to kill whales for consumption. An additional threat is the direct impacts of human activities on the oceans.

Global warming is not an empty word for oceans and marine biodiversity. Industrial fishing has been denounced for decades, but overfishing continues, ruining ecosystems. Unfortunately, this list of threats continues to grow: sea traffic is exploding, high-powered military sonar and explosive devices are used for underwater oil and geophysical exploration, the development of new offshore energy facilities, oil spills, chemical pollution by fertilizers, significant accumulation of plastic in the oceans, and there are more.

What is the role of research in this context?

Knowledge of the marine environment has never been more important than today. Yet, there is still much to discover. On cetaceans, scientists are working on different aspects to better understand them, better describe their interactions, and their habitats. The ultimate goal is that this new knowledge contributes to conservation policies.

The Jean Le Rond d'Alembert Institute at Sorbonne University studies active and passive underwater acoustics. We are interested in underwater acoustic landscapes, with the objective of having a better knowledge of ecosystems and better describing the effects of human activities. We collect data in all oceans and develop engineering and software for the automatic detection and location of cetaceans from their sound emissions.

What is your current research in bioacoustics? 

Research in bioacoustics is multidisciplinary including biology, ecology, engineering, signal processing, applied computing, genetics and other domains. For my part, I work on signal processing and I am currently involved in several projects:

  • Description of the vocal generator of large whales. The goal is to describe the laryngeal system of whales to study how they create sound emissions. We are working on mechanical models and computer simulations to model acoustic production.
  • Study of humpback whale songs. The description of the sound units composing the songs requires modern approaches to signal processing and pattern recognition.
  • Study of the interactions of mothers and their young in humpback whales. It is a question of studying the privileged relations between the females and their newborns, in particular to describe the different phases of learning.
  • Study of dolphin behavior. There is a major difficulty for cetacean sightings, particularly not being able to identify the individual who makes the sounds. We have developed a new tool, based on a 360 ° underwater camera associated with a network of 4 hydrophones. This device allows us to identify the behavior of dolphins to better understand their activities.

How do you identify whales from an acoustic point of view?

Cetaceans emit sounds for all their activities and social interactions. For some species, we speak of regional dialects, acoustic clans (sounds shared by a group). Each individual has an acoustic signature that can recognize it through the sounds it emits. Species are identified by frequency bands and the form of sounds that are emitted.

How can your research on whale songs help to better preserve them?

The better we know whales the better we can protect them and protect the entire ecosystem. Whales are "umbrella species", which means that protecting whales protects the ecosystem and the oceans in a broader way.

See and Read:

Chant des baleines - Cetamada
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