Fin Whale – Balaenoptera physalus

Common Name: Fin Whale
Scientific Name: Balaenoptera physalus
Classification: Kingdom Animalia → Phylum Chordata → Class Mammalia → Order Cetacea → Family Balaenopteridae → Genus Balaenoptera → Species physalus
IUCN Conservation Status: Vulnerable (VU)

Subspecies:

1. Balaenoptera physalus physalus – North Atlantic and North Pacific populations
2. Balaenoptera physalus quoyi – Southern Hemisphere population
3. (Balaenoptera physalus velifera) – Proposed Indian Ocean form (unconfirmed, possibly includes Sri Lankan individuals)

Geographic Range (where the species is found):

The Fin Whale is cosmopolitan, found in all major oceans, generally between 40°S and 75°N. In the Indian Ocean, sightings are infrequent but confirmed along the southern and eastern coasts of Sri Lanka, particularly near Trincomalee and deep offshore canyons. These individuals likely belong to the Southern Hemisphere population (B. p. quoyi). The species prefers temperate and subtropical deep waters, often near upwelling zones where prey is abundant.

Description:

The Fin Whale is the second-largest animal on Earth, reaching 18–27 meters in length and weighing up to 80 tonnes. It has a sleek, streamlined body, dark gray to brownish on top and lighter below. Its head is characterized by a prominent ridge and distinctive asymmetrical jaw coloration — the right lower jaw is white, and the left is dark gray, a unique trait among whales. The dorsal fin is tall, falcate, and located about two-thirds down the back. The blow is tall and narrow, reaching up to 6 meters high.

Habitat:

Prefers deep pelagic and continental slope waters, though occasionally approaches shelf edges and coastal upwellings. Around Sri Lanka, rare sightings occur in deep offshore zones, typically in areas with high plankton productivity such as Trincomalee Canyon and the southern deep-sea slopes.

Diet:

Carnivore (filter feeder).
Feeds primarily on krill (Euphausiids), copepods, and small schooling fish like anchovies and sardines. Uses lunge-feeding — engulfing large volumes of prey-rich water and filtering it through baleen plates (260–480 on each side).

Ecological Role of Balaenoptera physalus:

Acts as a top-level predator in pelagic ecosystems, controlling populations of krill and small fish. Its excretions provide nutrient recycling, enriching the euphotic zone with nitrogen and iron, which promotes phytoplankton growth and supports marine biodiversity.

Life Cycle:

Calves are born after an 11–12 month gestation period, measuring around 6–6.5 meters in length and weighing up to 2 tonnes. They nurse for 6–7 months and grow rapidly, gaining 60–70 kg per day. Sexual maturity occurs at 6–10 years, and adults can live 80–90 years in the wild.

Reproduction (mating season, number of offspring):

Breeding occurs in winter, usually in low-latitude subtropical waters. Females give birth to one calf every 2–3 years. After calving, mother and calf migrate toward high-latitude feeding grounds, although migration in the Indian Ocean is less well defined.

Behaviour:

Typically solitary or in pairs, though small feeding groups may form. Fin Whales are fast and agile swimmers, reaching speeds of up to 40 km/h — the fastest among baleen whales. They surface 4–7 times before taking a deep dive lasting up to 15 minutes. The species produces low-frequency sounds (16–40 Hz) for long-distance communication and possibly mating calls.

Key Adaptations:

• Asymmetrical jaw coloration — possibly improves prey herding and feeding efficiency.
• Streamlined body and powerful tail for fast swimming.
• Efficient oxygen storage for prolonged dives.
• Large pleated throat grooves enabling vast water intake during feeding.
• Low-frequency communication enabling contact over hundreds of kilometers.

Threats:

• Ship strikes — increasing risk in busy Indian Ocean shipping lanes.
• Noise pollution — interferes with communication and navigation.
• Entanglement — occasional in deep-sea fishing gear.
• Pollution — accumulation of toxins and ingestion of microplastics.
• Climate change — alters krill distribution and prey availability.
• Historic whaling — drastically reduced global numbers; recovery remains slow.

Interesting Fact:

Fin Whales have been recorded swimming at speeds exceeding 40 km/h, earning them the nickname “the greyhounds of the sea.” Their asymmetrical jaw pattern is so distinctive that it’s used by scientists to identify individuals during field research.

Here are authoritative anchor-text references for the Fin Whale (Balaenoptera physalus), ready for direct use in scientific writing, blog posts, or educational resources:

REFERENCES

• NOAA Fisheries – Fin Whale – U.S. government species profile with detailed information on biology, threats, and conservation efforts.
• IUCN Red List – Balaenoptera physalus – Global conservation assessment, population trends, and identified threats.
• IWC Handbook – Fin Whale – International Whaling Commission data covering management, population recovery, and distribution.
• NAMMCO – Fin Whale – North Atlantic Marine Mammal Commission facts on identification, feeding, and seasonal migration.
• Whale and Dolphin Conservation – Fin Whale – Accessible summary of ecology, conservation status, and global occurrence.
• OBIS-SEAMAP – Balaenoptera physalus – Global distribution and observation records from scientific surveys.

Dive into our marine-inspired gift collection — perfect for ocean lovers and wildlife enthusiasts alike. Explore eco-friendly T-shirts, including our whale, sea star, and shark designs made from soft organic cotton. Pair them with our ocean-themed stickers, dolphin and shark tote bags, nature-inspired notebooks, eco-friendly scrunchies, and wildlife print bandanas — thoughtful, sustainable pieces that celebrate the beauty of marine life