There are several threats to cetaceans worldwide:
- Incidental capture in fishing nets;
- Increased boat traffic, which leads to collisions with whales at sea;
- Degradation of marine environments caused by human-induced pollution;
- Changes in global climate, which produce changes in aquatic environments.
Most whale populations have survived the worst of all threats: commercial whaling. The irrational exploitation of whale meat and oil between the 16th and 20th centuries severely affected global whale populations, eliminating certain populations and leading others to near-extinction.
Since 1987, whaling for commercial purposes has been prohibited, but Japan still hunts minke whales, sei whales and sperm whales in the North Pacific and Antarctic oceans for scientific purposes. In addition, Norway hunts minke whales in the North Atlantic, openly challenging the international ban.
In many places, smaller cetaceans are hunted including by countries that consider these animals an important source of food or trade.