Blue Whale

Details

Blue whale (Balaenoptera musculus) is the largest animal ever known. A rorqual in the familyBalaenopteridae, it feeds primarily on krill via high‑speed lunge feeding with expandable ventral pleats and baleen plates for filtration. Calls extend into the infrasonic range, propagating across ocean basins. IUCN: Endangered (EN).

Basics

• Scientific name: Balaenoptera musculus

• Length: typically 24–30 m (larger extremes recorded)

• Mass: about 80–150 t (seasonal/individual variation)

Ecology & Behaviour

Targets dense krill swarms in productive systems (upwellings, polar fronts). Summers at high‑latitude feeding grounds; winters at mid‑ to low‑latitude breeding areas. Usually solitary or in small parties; looser aggregations form at rich prey patches. Dives commonly 10–20 min; much longer dives occur. Blow is tall and vertical, visible from afar.

Identification

Blue‑grey mottled “marbled” body; very small dorsal fin set far back; long, streamlined body; 60–90 ventral grooves. When surfacing, the long back “rolls” with a small dorsal fin appearing late; blow ~9–12 m and vertical.

Subspecies & Range

• B. m. musculus (Northern Hemisphere blue whale): North Atlantic & North Pacific.

• B. m. intermedia (Antarctic blue whale): Southern Ocean, typically larger.

• B. m. brevicauda (pygmy blue whale): Indian Ocean–W Pacific, smaller with subtly different proportions.

Threats & Conservation

• Historic industrial whaling left severely reduced populations.

• Ship strikes & entanglement in busy shipping corridors and fixed‑gear fisheries.

• Noise & climate change affecting communication and krill distribution.

Measures: vessel speed/routing management in hotspots, quieter‑ship initiatives, gear modifications/ropeless trials, anddynamic spatial protection guided by real‑time prey/habitat monitoring.