This cosmopolitan species is the largest animal on the planet. They weigh as much as 200 tons and their calls can be as loud as 188 decibels! The global population is in the range of 10,000 to 25,000.
The main threat in the past was direct exploitation, which only became possible in the modern era using deck-mounted harpoon cannons. Blue whale hunting started in the North Atlantic in 1868 and spread to other regions around 1900 after the northeastern Atlantic populations had been severely reduced. The Antarctic and North Atlantic populations were probably depleted to the low hundreds by the time whaling ceased.
Blue whales have been protected worldwide since 1966, although they continued to be caught illegally by former USSR fleets until 1972. The last recorded deliberate catches were off Spain in 1978.