What is the main reason why dolphins are endangered?

Bycatch is the accidental capture of non-target species in fishing gear. It's a major threat to dolphins, which frequently become stuck in fishing nets and drown or are injured. Dolphins can also experience barotrauma, a condition that occurs when a rapid change in pressure causes the tissues of the animal's body to expand or collapse. This can happen when the dolphins are brought to the surface too quickly after being caught.