echolocation is a main sense that all dolphins use to navigate and pinpoint prey and predators. dolphins and whales use echolocation by bouncing high-pitched clicking sounds off underwater objects, similar to shouting and listening for echoes. the sounds are made by squeezing air through nasal passages near the blowhole. these sound-waves then pass into the forehead, where a big blob of fat called the melon focuses them into a beam. this process can be interrupted by large composites of waste that can range from oil, plastics and noise. the large blockage can refract sound-waves that give the dolphin a false inclination that there is possible prey, kin or a predator in the area. this can become confusing and frustrating which can lead to extreme stress and potential health issues. despite echolocation being mostly affected by noise pollution it can altered by pollutants in marine water.