Michael Jasny's Blog: Reviving the World's Oceans

Scientists to Obama: Less Ocean Noise, Please

2009-10-07T19:44:04Z

If, like me, you're desperately concerned about the fate of the oceans, probably the most hopeful development this year is President Obama's launch of a new National Oceans Policy. The task force he convened in June recently came out with its Interim Report and, as my colleague Sarah Chasis wrote at the time, there's much to celebrate. Still, in a high-level document, there were bound to be a few omissions. One of the most salient - as a group of scientists said in a path-breaking statement released today - is the growing problem of undersea noise.

Navy sonar has received the lion's share of media attention, but it's not the only noise-maker in the sea. Biologists are deeply concerned about the gamut of sources that are contributing to this rapidly rising form of pollution: not just sonar, but also airguns used in oil-and-gas exploration, supertankers and large cargo ships, pile-drivers and dredgers used in construction, and on and on. When whales turn up on the beach with bleeding around their ears, we know there's a serious problem; ironically, the chronic noise that's destroying the ability of whales and other species to hear, feed, and find mates is more of a silent killer.

Today's statement from a group of marine scientists describes the problem eloquently:

The ocean is a world of sound. Animals such as whales, dolphins, and fish depend on hearing for communicating, foraging, finding mates, detecting predators, and maintaining family and social groups. Human activity is rapidly altering the ocean's natural acoustic habitats. Industrial and commercial underwater noise propagates over enormous distances, affecting millions of square miles of ocean. For example, background noise at the same low frequencies vital to many marine species has increased 100-fold in some locations over the last 50 years. This growing fog of noise is shrinking the perceptual world of whales and other marine life, undermining their ability to "see" with sound. Chronic noise exposure is a recently recognized, largely hidden threat that can reduce long-term survival rates, while exposure to loud noise can result in injury, and even death in certain circumstances. Today few places in the world's oceans remain free of noises from human activities.

The profile of the issue is almost certain to grow. At this moment, Interior Secretary Salazar is deciding whether to open portions of the outer continental shelf to new oil and gas exploration; some states, like Florida, are considering drilling right along the coast; and environmentalists fear a new and untrammeled Gold Rush in offshore development.

With all of this activity looming, the scientists are clear about what's needed. They urge President Obama towards an ocean policy similar to our successful "no net loss" of wetlands policy of the 1990s: "that no net increase in ambient noise occurs in U.S. coastal waters and that a schedule be established to realize substantial reductions in ocean noise by 2020." Remarkably, they write, many of the tools needed to curb the problem are currently available or soon will be.

What is needed - of course and as always - is the political will. Inclusion of undersea noise in the National Oceans Policy would make a very good start.

Navy Games

2009-04-09T22:23:26Z

The Obama Administration has put a premium on good science in environmental policy, but some folks in the Navy don't seem to have gotten the message.

In a study soon to be published in Biology Letters, researchers exposed a captive bottlenose dolphin to recordings of Navy sonar and then gave the animal a hearing test, to see whether it suffered hearing loss. In fact, the study is the latest in a line of similar experiments that the Navy has sponsored, usually on bottlenose dolphins since the Navy maintains several of the animals in captivity. In this case, it took higher sonar levels to produce hearing loss in that one animal than might have been predicted from earlier studies.

That's useful to know, and it adds to our existing knowledge about sonar's effects on marine mammal hearing. The problem is that the Navy, hungry for any science that might justify its recalcitrance on sonar policy, wants it to mean a lot more than it says.

Simply put, studies of hearing loss like this one don't address the central concerns that scientists have about sonar: its widespread impacts on marine mammal behavior, its long-term effects on marine mammal health, and its startling capacity to injure and kill certain species of whales.

Let's take mortalities first. Deep-diving beaked whales - exposed to levels of sonar much lower than those needed to cause hearing loss - have consistently turned up with hemorrhaging in their brains and emboli in their livers and other organ tissue. The leading theory is that Navy sonar drives them to alter their highly-evolved dive patterns in ways that induce "bends"-like injuries. This view is supported by multiple peer-reviewed articles on dive physiology, tissue pathology, and other subjects. And while a number of other mechanisms remain possible (an expert workshop organized by the U.S. Marine Mammal Commission identified several), hearing loss is not among them.

How to prevent these injuries is a deadly serious problem given that beaked whales make up one-sixth of all marine mammal species on earth. But the new study doesn't move us any closer to a solution and, quite reasonably, doesn't attempt to.

Nor does the new study contribute to our knowledge of an even more important problem: sonar's impacts on whale behavior. Navy sonar is known to cause whales and other marine mammals to stop vocalizing and feeding, to abandon habitat, to panic, to put themselves at risk of ship collision, and, in some cases, to strand and die. These impacts occur in some species at very low levels of sonar exposure and affect vast numbers of animals. Even the Navy estimates that its exercises off the coastal United States would significantly impact marine mammals more than 2 million times each year. All of these behaviors may be critical to survival, not just of individual animals but of entire populations, many of which are already endangered or depleted.

The new study has little, if anything, to say about these critical behavioral effects, and rightly so. "Boris," the dolphin used in the experiment, wasn't a wild animal or even an ordinary captive animal, but one that was specifically trained for years to stay on task during experiments.

But that won't stop the Navy from spinning the study as though it were some Archimedean lever displacing years of research on completely different issues. Hopefully, the press will put on the brakes.

Whales and Oil

2008-06-19T19:00:34Z

As offshore oil gets dragged once again onto the political scene, it’s worth remembering the environmental costs that led to the adoption of an offshore moratorium in the first place.

One of the seminal events in the modern environmental movement was the 1969 blow-out of Union Oil Platform A, which sent millions of gallons of crude into the Santa Barbara Channel and tarred beaches for miles along the California coast. The Santa Barbara spill became an object lesson for the hazards of offshore drilling, a lesson that has since been relearned in the Gulf of Mexico, the Black Sea, and many other locales here and abroad. But even aside from the occasional headline-gathering calamity, the search for oil at sea remains an environmentally risky business, and not only for its direct effects on humans.

Two weeks ago, for example, some 200 melon-headed whales stranded in the shallow waters of Loza Bay on the northwest side of Madagascar. ExxonMobil had been conducting an oil-and-gas survey nearby, using sonar a few days prior to the strandings to map the seafloor and later booting up powerful airguns to look for deposits below.

Melon-headed whales are deep-water animals that very seldom strand but seem acutely sensitive to man-made noise. A huge pod of melon-heads came into Hanalei Bay, on Kauai, in July 2004 as the U.S. Navy ran a major sonar exercise offshore. In that case residents managed after a day of struggle to lead the whales back out to sea, but the news from Madagascar is grim by comparison, with more and more animals reported dead. ExxonMobil suspended its operations, and an investigation into the strandings has begun.

Biologists who’ve looked at the problem of oil-and-gas exploration are concerned less about mass strandings than about subtler, more far-reaching effects on marine mammals: things like habitat abandonment and interference with breeding and foraging, which are not so easily observed but are probably occurring on a population scale. The die-offs in Loza Bay are just a reminder of what offshore oil means for the creatures who live offshore.