Seasonal distribution, movements and taxonomic status of blue whales (Balaenoptera musculus) in the northern Indian Ocean

摘要: There is a distinct population of blue whales, Balaenoptera musculus, in the northern Indian Ocean. The taxonomic status these animals has long been uncertain, with debate over whether this represents subspecies, and if so which name should apply. They have most frequently assigned to B. musculus brevicauda, but are currently considered be m. indica. movements whales within Ocean poorly understood. This paper reviews catches (n = 1,288), sightings 448, minimum 783 animals), strandings 64) acoustic detections 6 locations); uses ocean colour data estimate seasonality primary productivity different areas Ocean; develops migration hypothesis. It suggested that feed Arabian Sea off coasts Somalia peninsula during period intense upwelling associated southwest monsoon (from about May October). At same time some also area coast India west Sri Lanka. When dies down October–November upwellings cease. then disperse more widely eke out leaner months northeast (during December March) other localised seasonally high productivity. These include east Lanka, waters Maldives, vicinity Indus Canyon (at least historically), parts southern consistent hypothesis at Lanka monsoon. appear migrate eastwards past north Maldives south December–January, returning westwards April–May.