Observations on an Aggregation of Grey Reef Sharks (Carcharhinus amblyrhynchos) in the Mozambique Channel Off the Coast of Nosy Be (Madagascar) and Tools for Photo-Identification—A New Aggregation Nursery Site?

2024/08/26 by Primo Micarelli, Marco Pireddu, Damiano Persia +7 · 1 voice
Environmental Science · #Ichthyology and Marine Biology #Marine Ecology and Invasive Species #Marine animal studies overview

paper · pdf · doi:10.3390/biology13090661

openalex publication_date 2024/08/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23

Abstract

Following preliminary underwater observations of about 1000 h carried out monthly between 2012 and 2023 (except the years 2021 and 2022), 23 specimens of grey reef sharks were spotted and photo-identified off the coast of Nosy Be in Madagascar, on an emerging reef called "Mokarran" at a depth between 15 and 30 m. Over 10 years of observations, eight specimens were re-sighted, identified with a non-invasive photo-identification technique of part of the first dorsal and the caudal fin, and one specimen was re-identified after 1982 days from the first sighting, i.e., after more than 5 years. In addition, six specimens of probably pregnant females were also identified in the same area. The population was entirely made up of females. The aggregation area could represent a new nursery site which, if confirmed after further investigations, will require greater protection.

Citations

• Shark nursery areas: concepts, definition, characterization and assumptions

Discussions

• Observations on an Aggregation of Grey Reef Sharks (Carcharhinus amblyrhynchos) in the Mozambique Channel Off the Coast of Nosy Be (Madagascar) and Tools for Photo-Identification—A New Aggregation Nur [bsky, 1 points, 0 comments]

Related

• The Needle in the Haystack: Uncovering the First Whale Shark ( <i>Rhincodon typus</i> ) Aggregation in the Coral Sea
• Insights into the structure of grey reef shark aggregation, <scp> <i>Carcharhinus amblyrhynchos</i> </scp> ( <scp>B</scp> leeker, 1856), in two distinct channels of the <scp>M</scp> aldivian archipelago, <scp>I</scp> ndian <scp>O</scp> cean
• Opportunistic sighting of a silky shark (<i>Carcharhinus falciformis</i>) aggregation in the subtropical southwest Atlantic
• A blacktip's black tip: The reliability of using dorsal‐fin patterns for photo identification of blacktip reef sharks (<i>Carcharhinus melanopterus</i>)
• First insights into the population characteristics and seasonal occurrence of the great hammerhead shark, Sphyrna mokarran (Rüppell, 1837) in the Western Tuamotu archipelago, French Polynesia