Michel Vely

The Comoros archipelago is situated in the northern Mozambique Channel. The islands of Moheli, Anjouan and Grande Comore (Union of the Comoros) constitute volcanic islands, and are a proposed migration destination for humpback whales. Cetaceans have never been studied in the area and preliminary small boat-based surveys were conducted during the austral summer of 2002 and 2003. These surveys were primary dedicated to the assessment of the occurrence of humpback whales (Megaptera novaeangliae), but other cetacean species were also recorded. The collation of opportunistic sighting records was also used to provide information on the diversity of marine mammals inhabiting this area. A total of fourteen marine mammal species were recorded around the Union of the Comoros, including the dugong (Dugong dugon), humpback and sperm whale (Physeter macrocephalus), spinner dolphin (Stenella longirostris), pantropical spotted dolphin (Stenella attenuata), Fraser’s dolphin (Lagenodelphis hosei), b...

Movements of humpback whales Megaptera novaeangliae  among breeding regions within the southwestern Indian Ocean are poorly understood. Understanding the relationships among breeding regions is critical for effective  conservation and management strategies. Through systematic comparisons of molecular genotypes and both systematic and non-systematic comparisons of individual identification photographs collected between 1996 and 2006, we have  thus far identified nine whales (six males and three females) utilising two breeding areas within this region: the northern Mozambique Channel and eastern Madagascar. Four of the nine whales were recaptured using only photographic data, two whales were independently recaptured using both photographic and genetic data, and three whales were recaptured exclusively using molecular methods. The discovery of these nine individuals provides much-needed data to guide the formulation and future revision of stock boundaries. Keywords : conservation, gene...

The coastal waters of the southwest Indian Ocean (including Mozambique, Tanzania, Kenya, the Seychelles, Comoros, Mayotte, Madagascar and the Mascarenes and their EEZ) countries are characterized by a high marine biodiversity. This paper review information on the diversity, distribution and conservation issues to cetaceans in this region. To date, up to 33 species of cetaceans have been recorded in the southwest Indian Ocean: 16 delphinids (Stenella longirostris, Stenella attenuata, Stenella coeruleoalba, Delphinus spp., Steno bredanensis, Grampus griseus, Sousa chinensis, Tursiops truncatus, Tursiops aduncus, Globicephala melas, Globicephala macrorhynchus, Pseudorca crassidens, Orcinus orca, Lagenodelphis hosei, Feresa attenuata, Peponocephala electra), 8 large toothed whales (Physeter macrocephalus, Kogia sima, Kogia breviceps, Mesoplodon pacificus, Mesoplodon densirostris, Mesoplodon mirus, Ziphius cavirostris, Mesoplodon gingkodens) and 7 baleen whales (Megaptera novaeangliae, B...

Ce rapport de mission presente les travaux realises entre le 16 janvier et le 15 fevrier 1995 sur et a propos des mammiferes marins du parc national du Banc d'Arguin, Mauritanie. Ceux-ci ont porte sur : a) un travail de terrain : la collecte d'echantillons resultants d'echouages recents ou anciens le long du littoral continental et des iles du banc d'Arguin; l'observation aerienne a partir d'un avion de tourisme; l'observation depuis le bord a l'aide de vehicule ou a pied; l'observation a partir des embarcations traditionnelles imraguen a voile latine, les lanches; b) un travail au laboratoire : etiquetage et preparation des crânes et calvariums; traitement et analyse des contenus stomacaux. (Resume d'auteur)

Background An aggregation of juvenile whale sharks were first reported off Arta, Djibouti, in 2003 and formally investigated in 2006. Standardised monitoring started in 2009 to establish the demographics of this aggregation and how it relates to the broader Red Sea and Indian Ocean whale shark population. Approach Photo-identification images have been collected from 2003 to present. Satellite relayed archival tags have been deployed to show longer term movements and tissue samples have been collected for DNA. Plankton and environmental information are routinely recorded. For the last two years digital Photo-IDs were collected by volunteers at the local dive operation to enable a longer annual study period to help establish seasonality and sighting trends. Results During 2003–2015, a total of 503 individual sharks were identified by photo-identification from more than 6300 in-water encounters; a maximum of 181 individuals were recorded in a single year. Overall 85% of sharks identified were males and mean body total length ranged from 3.5–4.3 m among years, with no significant difference between sexes. Sharks which were sighted in more than one year had a mean period of inter-annual residency of 4 years (maximum 11 years, n=3). Using data from 2003–2015, mark and recapture models estimated a gross population of 660–777 with 53–78% of individuals being re-sighted in any one year. Satellite tag data showed tagged individuals left the immediate area and travelled into the Red Sea and Northern Indian Ocean; however, 2 of the 3 PAT tagged sharks were seen off Djibouti in subsequent years. Diving depth data showed all sharks made short duration dives to depths greater than 400 m (maximum 832 m) but that all spent at least 45% of the time within 10 m of the surface and an average of 73% of the time shallower than 40 m. Comparison with plankton and environmental data showed that sharks were associated primarily with high plankton concentrations and swimming crab (possibly Charybdis erythrodactyla) spawning events. Conclusions The Arta area off Djibouti is host to a regular and significant aggregation of whale sharks. The average size of the sharks is smaller than those found in other Indian Ocean coastal aggregations suggesting that this may be an intermediate or kindergarten group from which the sharks will leave as they grow to join other juvenile aggregations. Satellite tracking and photo ID support the movement of sharks into Red Sea aggregations.

Megaptera, an association for knowledge, observation and conservation of marine mammals, has conducted monitoring on humpback whales (Megaptera novaeangliae), at Isle Sainte-Marie, Madagascar (site 1), and around the four islands of the Comoros Archipelago (site 2). Monitoring was carried out on board ecotourism boats, during the whales’ migration to breeding grounds in the austral winter, from 1999 to 2008. The objectives of this study were to better understand: (1) humpback whales movements in Western Indian Ocean, within the same site and between the two sites, both within and between seasons; and (2) the significance of the two sites for humpback whale reproduction. Flukes identification photos have been obtained from more than 500 individuals from site 1, and more than 150 from site 2. More individuals, photo-identified by one or both sides of the dorsal fin at both sites, and fluke photo-IDs collected from 1994 to 1997 at site 1, were added to this study. Whales appear to be m...

The coastal waters of the southwest Indian Ocean (including Mozambique, Tanzania, Kenya, the Seychelles, Comoros, Mayotte, Madagascar and the Mascarenes and their EEZ) countries are characterized by a high marine biodiversity. This paper review information on the diversity, distribution and conservation issues to cetaceans in this region. To date, up to 33 species of cetaceans have been recorded in the southwest Indian Ocean: 16 delphinids (Stenella longirostris, Stenella attenuata, Stenella coeruleoalba, Delphinus spp., Steno bredanensis, Grampus griseus, Sousa chinensis, Tursiops truncatus, Tursiops aduncus, Globicephala melas, Globicephala macrorhynchus, Pseudorca crassidens, Orcinus orca, Lagenodelphis hosei, Feresa attenuata, Peponocephala electra), 8 large toothed whales (Physeter macrocephalus, Kogia sima, Kogia breviceps, Mesoplodon pacificus, Mesoplodon densirostris, Mesoplodon mirus, Ziphius cavirostris, Mesoplodon gingkodens) and 7 baleen whales (Megaptera novaeangliae, B...

ABSTRACT New West African specimens of Stenella clymene, the Clymene dolphin, are evidence that the present unequal distribution of this species in the western and eastern parts of the tropical North Atlantic could be an artifact of poor sampling in African waters.

Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried ...

Abstract—The identification of individual animals over temporal and spatial scales can provide robust estimates of population size and distribution. While marker tagging can provide an option to achieve this, it can be problematic both in terms of tag loss and the associated difficulties and effects of attaching the tags. Photoidentification of distinctive characteristics which remain stable over time has replaced tagging in some species but usage at regional scales has been hampered by a lack of standardisation of matching ...