Page 90 - Livre_MOW2021_EN

88 | BLUE INNOVATIONS

A NEW ERA AN ACOUSTIC POSTCARD
OF THE LAST CENTURY
A world first, this work marks the start of “a new era
of ocean observation”, the researcher explained, sup-
porting the prevention of noise pollution and risks of In spring 2020, the “Quiet Sea” mission also offered
collision. “These vortexes attract cetaceans as they very valuable results. “The mission was able to seize
are very rich in nutrients and therefore prey. They are this extraordinary scientific opportunity to study ma-
even partially visible from space”, noted Hervé Glotin, rine mammal populations without the disruption of
whose team works with the European Space Agency noise pollution” Philippe Mondielli added enthusias-
in order to predict them, and to better understand the tically, who had offered his support. From Toulon to
needs of super-predators through bioacoustic analy- Monaco, 400 kilometres of coastline - amongst the
sis using nautical drones and Bombyx smart acoustic busiest in the world - returned to the calm of pre-in-
buoys. These predators play a fundamental role in the dustrial times. Ideal conditions for cetaceans to visit
food chain, but there are no more than one thousand the coast. Differences of 6 decibels RMS were re-
7
in the north-west Mediterranean. Protecting them re- corded along the coast and at sea, where coastal
quires convergence between experts and challenges, traffic continued, which is a value corresponding to
as this mission shows. a “very deep silence”, explained Hervé Glotin, “which
allowed us to record sounds made by cetaceans in
very high definition, even at sites usually deeply af-
fected by noise pollution”. Other indicators demons-
trated the benefits of a significant decline in human
activities in the area, such as a sharp drop in hydro-
carbons dissolved in the water.

Many questions on the Monaco Ocean Week chat
allowed the mission’s representatives to offer details
on these promising results, which reveal a hidden
Mediterranean.

“The mission was able to seize this
extraordinary scientific opportunity to
study marine mammal populations without
the disruption of noise pollution”

© D.Luquet - IMEV 7. RMS (Root Mean Square) is an average noise volume heard overall,

thus depending on a certain recording time.