Are Scientists Deaf to Sonic Blasting’s Harm to Dolphins and Whales?
The Atlantic Ocean off the United States' East Coast may soon become an extremely noisy place, as proposals pile up to map the seabed with high-decibel sonic blasts that can hurt dolphins, whales, and other marine life.
The latest study, proposed by the U.S. Geological Survey, Lamont-Doherty Earth Observatory, and the National Science Foundation, will seek to define the outer reaches of the continental shelf and learn more about the potential threats of tsunamis generated by underwater landslides. The National Marine Fisheries Service has given preliminary approval for the project.
The study comes on the heels of recently approved seismic testing of sediments deep beneath the ocean floor off the New Jersey Shore to document shifting climate-change patterns over the millennia. And last week, the Obama administration announced it will allow energy companies to use sonic blasts to explore for offshore oil and gas deposits from Delaware to Florida. Hydrophones will record the reverberations, which will be used to create maps of potential fossil fuel reserves.
For the tsunami project, air guns would send sonic blasts as loud as 265 decibels toward the ocean floor every 20 to 24 seconds for 34 days, sound that could travel for thousands of miles. The testing is set to be carried out over the next year.
The noise could disrupt the communication, foraging, and breeding behavior of dolphins and whales. According to NMFS, intense underwater sound pulses can produce temporary or permanent hearing loss in marine mammals, as well as "stress, neurological effects, gas, bubble formation in the blood or tissues, and other types of organ or tissue damage."
A similar seismic expedition in the Gulf of California in 2002 caused beaked whales to strand themselves on beaches, prompting a federal judge to order a halt to the operation.
"The Atlantic Ocean is now facing a triple-threat of seismic blasting activity, and two of these three projects are in the name of research," Cassandra Ornell, a scientist at Clean Ocean Action, a New Jersey environmental coalition, said in an email.
"These multiple seismic surveys off the Eastern Seaboard could lead to cumulative, long-term impacts to marine life, especially endangered species such as the North Atlantic right whale and the loggerhead sea turtle," she added.
Several seismic studies have already been conducted around the Atlantic Ocean, according to Ornell. "We want to know why existing data cannot be reprocessed to address the questions these surveys seek to answer," she said.
Clean Ocean Action, which submitted its comments to NMFS on Wednesday, called for a full environmental impact study before allowing the tsunami project to begin. It argued that seismic testing should not be done during the spring and summer, when many marine species are actively feeding, breeding, and calving off the mid-Atlantic seaboard.
If NMFS gives final approval, researchers will be permitted to disturb 19,497 marine animals, including 34 whale and dolphin species, six of which are endangered.
According to USGS, only a small part of known populations of most species will be affected. But an estimated 11 percent of endangered fin whales in the region will be harassed and nearly 22 percent of pantropical spotted dolphins.
NMFS acknowledges that there isn't any current population data available for eight marine mammal species that may be disturbed.
The USGS says it will reduce testing to just one air gun when marine mammals are nearby. If migrating right whales are spotted, blasting will halt for 30 minutes.
The agency insists that the precautions mean no animals are expected to be injured during the seismic testing.
If testing proceeds, environmentalists worry that marine mammals of the western North Atlantic may soon have few places to hide from deafening air guns.