Off Nosy Be, in northern Madagascar, swims a whale that science only confirmed seeing alive in 2015. It isn't a newly discovered species — it was formally described back in 2003 — but for more than a decade it was known only from skeletons, captured specimens and a single stranded animal. Omura's whale became, almost by accident, one of the most recent large marine mammals ever documented alive for the first time, and the waters off this archipelago were part of that story.
Omura's whale (Balaenoptera omurai) was described as a species in 2003 by Japanese researchers Shiro Wada, Masayuki Oishi and Tadasu Yamada, in the journal Nature, based on nine specimens: eight caught by Japanese research vessels in the Indo-Pacific in the late 1970s, and one stranded at Tsunoshima, in the Sea of Japan, on 11 September 1998 — an 11.03-metre adult female that became the species' holotype. The name honours Japanese cetologist Hideo Omura. Until 2015, none of these animals had ever been observed or studied alive, in the ocean, by a scientific team.
That gap began to close between 2011 and 2014, when a team led by researcher Salvatore Cerchio, of the New England Aquarium and the Woods Hole Oceanographic Institution, started surveying the waters off northwest Madagascar regularly. Over those four years, they logged 44 confirmed sightings — 13 in 2013 and 25 in 2014 — mostly in continental shelf waters averaging around 31 metres deep. Of those 44 sightings, 42 occurred off Nosy Iranja and the Ampasindava Peninsula; only two were recorded directly off Nosy Be itself. Older historical records from the area also exist, from 1991-1995, 1998 and 2000, including a November 1994 photograph showing around a dozen whales feeding together at the surface. The findings were published in October 2015 in the journal Royal Society Open Science, with the first field observations and images of the species ever published while alive.
Physically, Omura's whale resembles a miniature fin whale, with an asymmetrical colour pattern unusual among rorquals: the lower jaw is dark grey on the left side and has a white patch on the right, with a pale chevron across the back. The most reliable field marker is a single ridge on the rostrum — Bryde's whale, with which it's often confused, has three — alongside a notably falcate dorsal fin. In the Madagascar sightings, adults measured between 8 and 12 metres and calves between 3 and 5 metres, figures close to the nine originally described specimens (9.6 to 11.5 metres). A 2006 genetic study (Sasaki and colleagues) confirmed it represents a very old rorqual lineage, one that split off before Bryde's and sei whales diverged from each other.
Worth being clear about one thing: this isn't, for now, a tourism product. No operators in Nosy Be sell dedicated Omura's whale-watching trips, and the overwhelming majority of the scientific sightings happened in the channel between the island and the Ampasindava Peninsula, not off the beaches where visitors typically stay. Even so, it's the same stretch of water that anchors island life — most visitors base themselves at Ambatoloaka, the main hub for restaurants and nightlife southwest of Hell-Ville, or further north at Andilana, a quieter reef-sheltered bay where the falling tide exposes a sandbar out to a rocky islet offshore. Nosy Be has a tropical climate, with a dry season running roughly from June to September — the more predictable window to visit — and a wet season from October to May, with daytime temperatures around 30°C year-round. Access is through Fascene Airport (NOS), close to Hell-Ville, the island's main town.
The International Union for Conservation of Nature (IUCN) currently lists Omura's whale as "Data Deficient" — not because the species is necessarily threatened, but because there still isn't enough population data to assess it rigorously. It's listed on CITES Appendix I, which restricts international trade, and on Appendix II of the Convention on the Conservation of Migratory Species. The main identified threats include bycatch in fishing gear and ship strikes, alongside recorded cases of artisanal whaling in the Philippines and Indonesia.
Omura's whale remains, today, one of the least-studied large whale species on the planet. But thanks to the fieldwork carried out off Madagascar between 2011 and 2014, it's no longer just a name attached to museum bones — it's an animal that, in the waters off this archipelago, scientists finally watched swim.
Not through an organised tourism product. The scientific sightings happened mostly in the channel between Nosy Be and the Ampasindava Peninsula, from research vessels — no operators in Nosy Be currently sell trips dedicated to this species.
The IUCN lists it as "Data Deficient," meaning there isn't enough population data to determine whether it's threatened — not that it's confirmed safe. It's protected under CITES Appendix I.
The most reliable way to tell them apart at sea is the rostrum: Omura's whale has a single ridge, while Bryde's whale has three.
The dry season, roughly June to September, is the more predictable window, with daytime temperatures around 30°C year-round.
Picked by the editorial team.
