How many blue whales are there?

Current Blue Whale Population

The global blue whale population is estimated at between 10,000 and 25,000 individuals. While this number may seem significant, it represents only about 3 to 7 percent of their pre-whaling population, which scientists believe once exceeded 350,000 animals worldwide.

Population Estimates by Region

Blue whale populations exist in all major ocean basins, though in much smaller numbers than historically:

Region	Estimated Population
North Pacific	1,500-2,500
North Atlantic	1,000-2,000
Southern Hemisphere (Antarctic)	5,000-15,000
Northern Indian Ocean	200-1,000
Total worldwide	10,000-25,000

The wide range in these estimates reflects the difficulty of counting animals that spend most of their lives underwater, migrate across entire ocean basins, and occur at low densities.

The Impact of Commercial Whaling

Commercial whaling in the 20th century devastated blue whale populations. Between 1900 and 1966, when the International Whaling Commission (IWC) banned blue whale hunting, an estimated 360,000 blue whales were killed — primarily in the Southern Ocean. The Antarctic population was reduced from an estimated 239,000 to fewer than 400 individuals by the mid-1960s.

The peak of blue whale hunting occurred in the 1930s, when over 29,000 blue whales were killed in a single season. The whales were hunted primarily for their blubber, which was rendered into oil used in margarine, soap, and industrial lubricants.

Recovery Progress

Since the 1966 hunting ban, blue whale populations have been slowly recovering. However, the rate of recovery has been much slower than for some other whale species:

• Humpback whales have recovered relatively well, with some populations removed from endangered species lists
• Blue whales continue to recover at an estimated rate of about 7% per year in some populations
• Antarctic blue whales remain at critically low numbers, with estimates suggesting only 1 to 3 percent of original population levels

The slow recovery is partly due to blue whales’ low reproductive rate — females produce one calf every 2 to 3 years after a gestation period of about 11 months.

Current Threats

Despite protection from commercial whaling, blue whales face ongoing threats:

• Ship strikes: Collisions with large vessels are a leading cause of blue whale mortality in some regions
• Ocean noise: Underwater noise from shipping and sonar can interfere with whale communication and feeding
• Climate change: Warming oceans may reduce krill populations, the primary food source for blue whales
• Entanglement: Blue whales occasionally become entangled in fishing gear

Blue whales remain listed as Endangered on the IUCN Red List. For more on blue whale conservation status, see how many blue whales are left.