hydroacoustic disturbance is another critical issue for dolphins. sources of noise can come from dredging, pile driving, increased vessel traffic, seawall construction, and soil improvement. for all cetaceans, sound is vital for providing information about their environment, communicating with other individuals, and foraging; also, they are very vulnerable and sensitive to the effects of noise. elevated anthropogenic sound level causes many dysfunctions of their behaviors, and even leads to death.