An article in today's New York Times science section details an effort by the National Oceanic and Atmospheric Administration to map the effects of human-generated noise in the ocean. Whether it's the drone of commercial shipping or the deafening blasts of seismic air guns, sounds that can travel for hundreds of miles, this noise has been on the rise for decades. For animals that depend on sound as their primary means for communicating or finding prey, this increasingly cacaphonous environment can have devastating consequences
The article articulates well the dangers posed to the ocean's inhabitants by an increasingly noisy ocean:
Sea mammals evolved sharp hearing to take advantage of sound’s reach and to compensate for poor visibility. The heads of whales and dolphins are mazes of resonant chambers and acoustic lenses that give the animals not only extraordinary hearing but complex voices they use to communicate.
In recent decades, humans have added raucous clatter to the primal chorus. Mr. Bahtiarian noted that the noise of a typical cargo vessel could rival that of a jet. Even louder, he added, are air guns fired near the surface from ships used in oil and gas exploration. Their waves radiate downward and penetrate deep into the seabed, helping oil companies locate hidden pockets of hydrocarbons.
Marine biologists have linked the human noises to reductions in mammalian vocalization, which suggests declines in foraging and breeding.
The sorts of air gun tests described above are currently being proposed for waters spanning from Delaware to Florida to search for oil and gas deposits. The Department of the Interior which is reviewing the proposal and will issue its decision sometime next year, estimates that those tests would injure 138,500 whales and dolphins.
In this case “injuring” often means literally deafening the animals. For whales and dolphins that use sound as the primary means to find mates, find food, and communicate, such as the North Atlantic right whale (of which there are an estimated 361 left on the planet) going deaf is equivalent to a death sentence.
The tests could also wreak havoc on the area's $12 billion fishing industry. Similar tests elsewhere have resulted in drops in catches of cod and haddock from 40 to 80 percent after the use of just a single airgun array.