Underwater photo-identification of sperm whales (Physeter macrocephalus) off Mauritius

The long-term monitoring of long-lived animals often requires individual identification. For cetaceans, this identification may be based on morphological characters observable from a boat such as shape, spots and cuts of the back, fluke and dorsal fins. However, for some species such as the sperm wh...

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Bibliographic Details
Published in:Marine Biology Research
Main Authors: Sarano, Véronique, Sarano, François, Girardet, Justine, Preud’homme, Axel, Vitry, Hugues, Heuzey, René, Sarano, Marion, Delfour, Fabienne, Glotin, Hervé, Adam, Olivier, Madon, Bénédicte, Jung, Jean-luc
Format: Article in Journal/Newspaper
Language:English
Published: Informa UK Limited 2022
Subjects:
Indian Ocean
Mauritius
protected species
monitoring
sperm whales
individual identification
Indian
Physeter macrocephalus
Online Access:https://archimer.ifremer.fr/doc/00779/89069/105098.pdf
https://doi.org/10.1080/17451000.2022.2040737
https://archimer.ifremer.fr/doc/00779/89069/
Description
Summary:The long-term monitoring of long-lived animals often requires individual identification. For cetaceans, this identification may be based on morphological characters observable from a boat such as shape, spots and cuts of the back, fluke and dorsal fins. However, for some species such as the sperm whales (Physeter macrocephalus), this approach may be challenging as individuals display a rather uniform skin pigmentation. They also do not very often show their fluke, complicating individual identification from a boat. Immature sperm whales that usually have an unharmed fluke may be excluded from photo-identification catalogues. Within the framework of the Maubydick project, focusing on the long-term monitoring of sperm-whales in Mauritius, passive underwater observation and video recording were used to identify long-lasting body markers (e.g. sex, ventral white markings, cut-outs of fins). A catalogue of 38 individuals (six adult males, 18 adult females and 14 immatures) enabled observers to record some nearly-daily, and yearly resightings. Advantages and disadvantages of this method are presented here. Such catalogues represent a robust baseline for conducting behavioural, genetic and acoustic studies in social species. Benefits of such newly acquired knowledge are of primary importance to implement relevant conservation plans in the marine realm. plement relevant conservation plans in the marine realm.

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