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Acoustic of cetaceans 

Acoustic is a science that Moidjio, led by Benjamin, has embraced since the early stage of it creation. These animals can be very vocal and exploit the water properties to emit a variety of sounds that will suit their needs for navigation, hunting, communicating, interacting with each others, singing ! We started our first recordings with hand made hydrophones aiming to collect the middle low frequency songs of Humpback whales and it was really challenging to get good affordable material. Time going, we had the chance to have hands on more performant hydrophones and recorders, allowing us to visualise higher spectrum of frequencies. 

Breaching humpback whale Comoros

Humpback whale, Comoros 2018

Humpback whale song, Comoros 2016

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Humpback whale vocal organ

Humpback whale

Since 2016, we are recording humpback whales songs in the Comoros. In 2018, we started a collaboration with 4 other organisations in the view to better understand the vocalisation pattern of humpback whales in the region and the communication and learning behaviour of humpbacks during the breeding season. 

Biagio Violi, PhD student from Genoa University, Italy, Vis-president of Menkab (Accobams partner and sister organisation), collected dozen of hours of whales vocalisation for the regional program. The program is supervised by Olivier Adams from the CNRS France.

song of the whale - Humpback Comoros.
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Humpback whale knock sound, Comoros 2016


Humpback whale song theme, Comoros 2016

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The mighty Spermwhale is a fantastic creatures that dives in the abyss of the oceans. It can reach up to 2000m depth in one dive and can hold his breath for long time and up to an hour. Spermwhales produce the most powerful and loud clicks of any cetaceans in the world. Their head is so big that clicks travelling within it are composed of multiple pulses. A first pulse (P0) is emitted by the right nostril by the contraction of a specific organ called the "monkey bag". This pulse travels all around but is concentrated backward through the "Spermaceti organ",  banging on air sacs located on the skull plate and refracted into the "junk organ" to create a second pulse (P1). Most of the energy is concentrated forward but some of the pulse is refracted backward, passing back to the spermaceti organ and Junk organ, creating a third pulse (P2). Moidjio CRCAD has recorded spermwhales in Comoros, Turkey, Greece and Italy in 2018 and 2019. We are suspecting a migrating population in the Comoros and our team has recorded it 2 years in a raw but no visual yet! 

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Spermwhale multi pulse click, Comoros 2018

Spermwhale Male Turkey

Mâle spermwhale, Türkiye 2018

 Spermwhales, Greece 2018


Spermwhale click, Egypt 2021

Pilot whales Comoros

Pilot whales, Comoros 2018

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Pilot whale

Pilot whales were recorded by Moidjio team in 2018. A pod of 15-20 individuals. A very beautiful recording made offshore Chindini village along the deep canyons of the South. Our recordings were made at less than 100m away from the pod. Pilot of Comoros produce whistles of relatively low frequency (6 to 10 KHz) with harmonics and synchronous clicks. 

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Pilot ComorosMoidjio
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Cuvier Beaked whale Savona

Cuvier beaked whales, Italy 2019

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Cuvier beaked whales click , Comoros 2018

Cuvier beaked whale

Cuvier's beaked whales (CBW) has a very typical click design and it can easily be identified. Easy to identify but hard to detect with hydrophones from boat! CBW are cryptic animals and spend most of their time underwater, going down to 3000m, along the canyons, emitting clicks, only when they reach depth of the order of 300m. While at depth and emitting clicks, CBW is facing downward to the seafloor and scan the area with a narrow beam of clicks emitted in a regular and slow pattern. Having a moored hydrophone seems the best option to detect these animals... Easy to identify, yes ! It is a very long click, the longest of the cetacean kind. In the order of 200 to 400 microsec, with a series of zero-crossing about 9-10, a typical peak-frequency at 35-40 KHz, lower if you are far and it visualise as a frequency sweep in time that represent the wigner plot as a upsweep coma

Risso's Dolphin

Risso's dolphin vocalisation is very particular and gives clews on how to identify it only by acoustic. Moidjio has worked at the analyse of Risso's vocalisation from Montenegro, Cyprus, Egypt and off-course Comoros and all have common features and more precisely within their clicks' characteristics. 

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Risso's MontenegroMoidjio
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Risso's dolphin Comoros

Risso's Dolphin, Comoros 2018

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Melon headed whale Comoros
Melon headed whale
Whistles and clicks - Melon headed Comoros
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Electra Moidjio
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pepono spaceMoidjio
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pepono rigoloMoidjio
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Pepono whistlesMoidjio
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pepono weird Moidjio
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Electra dolphin click spectra, Comoros 2016


Electra dolphins whistles and clicks, Comoros 2016

Spinner dolphins Comoros

Spinner dolphins, Comoros 2016

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Spinner dolphin
Whistles and Clicks - Spinner dolphins Comoros.
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Striped Dolphins

Stripped dolphins were recorded during a survey campaign in Montenegro with the Natural History association of Montenegro in 2018 and 2019. We collected the first acoustic samples of this species in the area. Stripped dolphins seems to be more active acoustically  along the edge of the continental slope and at night. This dolphin can be found in depth >200m along the Adriatic pit and is fairly common there.

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Stripped dolphin Montenegro
Pantropical spotted dolphin Comoros
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Pantropical spotted dolphins
Bottlenose dolphins Comoros

Bottlenose dolphin clicks and Whistles, Comoros 2016

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Bottlenose dolphin click spectra, Montenegro 2018

Bottlenose dolphin
False killer whales
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False killer whales Comoros

False killer whale, Comoros 2018

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Rough-toothed dolphin

Steno dolphins whistles, Egypt 2021


Steno dolphins Click, Brazil 2013


Steno dolphins click train, Egypt 2021

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