Cetaceans surveys by Moidjio CRCAD
We are using a 6m fibre glass boat
equipped with 2 engines.
We are surveying the waters of the south
Grande Comore, including the Marine
Park of the Coelacanth, the waters
around the Marine Park of Moheli and
the offshore canyons between the islands.
Our surveys, are of 2 types:
We are exploring areas of interest such as deep canyons and offshore area in order to
discover new species and habitats.
- Population study:
We are monitoring known populations evolving in known habitat.
We are trying to understand their range distribution, habits,
behaviour and acoustic specificities.
Species identification and GPS plotting:
It is very important to know your species and gives an accurate ID to each encounters. It is sometimes easy but sometimes really challenging. Deep divers such as spermwhales species, beaked whales, do not spent time at the surface and often shows really small part of their body to the surface. It is important to be well trained and confident on each ID.
GPS plotting helps to dress distribution maps that help to understand habitat use of the animals. Also knowing where animals evolves contribute to better conserve these habitats.
Cetaceans distribution in Comoros: Whales distribution / Dolphin Distribution.
What's that ?
The interest of the photo-identification is multiple and here we are looking at identify individuals within a population.
We want to follow this animal in the time but also in the space, assess if this individual is faithful to a group or to an area.
How that work?
We are trying to get pictures of body parts that can be recognisable form an individual to another.
Flukes work very well for humpback whales for example, and it is the best way to identify with certitude an individual. Unfortunately, our humpbacks like to rest in Comoros so they don't dive and don't show much their flukes. So what else???
The dorsal fin... yes that works but has it limitations. It works for identification of individuals within a local population and few individuals but at the scale of regional population it starts to show it limitation and for identification matching between populations that becomes too much of a challenge.
Simply we are trying to find ways to collect informations to resolve our detective work. Once in the computer, it patience work to match, classify individuals. Then it is an even bigger job to analyse data and understand movements, association, dissociations, life expectation, population dynamics.
Each Whale and dolphin, get a name and an identification number and we record date, time, behaviour, number of individuals in the pod.
Humpback whale distribution
Humpback whale distribution Grande Comores, Moheli 2009-2019
Curious mother and calf HW, Moheli 2009
Zone de recherche Moidjio Grande Comores, Moheli 2009-2019
Cetacean survey Grande Comores, 2019
Fluke ID Humpback whale, Grande Comores 2012
Dorsal fin ID Humpback whale, Grande Comores 2016
False Killer whales
Pygmy Killer whales
Melon headed whales
Pantropical spotted dolphins
Dwarf Minke Whales
Species encountered in Comoros by Moidjio CRCAD
Photo-Identification of cetaceans
Cuvier Beaked Whales
Blainville Beaked Whales
Hotula Beaked Whales