Photo: Tim Collins/WCS
A landmark report links ExxonMobil’s sonar tech to a mass stranding of whales off Madagascar.
by Jason Bittel @bittelmethis • October 2, 2013
Until a few years ago, most people in Madagascar had never seen a melon-headed whale. These cetaceans—which are actually a species of dolphin—typically spend their lives in the deep sea and almost never come near shore. But strangely, in the summer of 2008, a pod of 100 to 200 of them suddenly appeared in a mangrove estuary along the island’s northwestern coast. Before long, dozens of melon-headed whales became stranded on the beach. Despite Herculean efforts from specialists flown in from all over the world, at least 75 of the animals died from starvation, dehydration, and sun exposure.
The whales were buried in a mass grave. The news cycle moved on. And after a while, everyone seemed to forget about the mysterious strandings.
Now, five years later, an independent scientific review panel has concluded that it was Big Oil’s use of sonar technology that drove the whales from their deepwater habitat and onto Madagascar’s shores. ExxonMobil—seeking oil and gas in ever harder-to-reach places—conducted a kind of high-frequency sonar mapping on the Indian Ocean floor that messed with whale’s communication systems, the scientists say. The sonar scared or harassed the melon-heads to such an extent that it caused them to leave their normal deep-sea habitat in the open ocean and wind up in the shallow lagoon. Unlike other forms of acoustic noise we already know cause problems for marine mammals, the type of echosounder implicated in this case had, until now, been considered safe. But the report—published last week by the International Whaling Commission (IWC), an intergovernmental body that regulates whaling and whale conservation—says otherwise and could lay the foundation for a whole slew of new maritime regulations.
Read: A Sound Settlement to Protect Whales from Big Oil’s Noise
“Ocean noise has become one of the major conservation issues, certainly for marine mammals, on the planet,” says Michael Jasny, a senior policy analyst for the Natural Resources Defense Council (which publishes OnEarth). The high-frequency echosounders, he says, are just adding to this “hydra-headed problem.”
The hydra, a mythical beast with many regenerating heads, is an apt metaphor for the ocean noise issue, as those who fight to subdue it have their hands full. Battles are already underway to protest airguns (a seismic surveying method used by oil and gas companies), long-range low-frequency sonar (those blip-blip-blips used by submarines), and even the simple, but disruptive, noise from passing ships. Up until now, echosounders didn’t make this list. The thinking went that high-frequency waves dissipated quickly in seawater and that marine mammals couldn’t hear them.
However, the IWC found that the noise from Exxon’s 12-kilohertz, multi-beam echosounder system “would have been clearly audible over many hundreds of square kilometers of melon-headed whale deep-water habitat areas.” And as it turns out, toothed whales—which include the melon-heads—hear pretty well in the mid- to high-frequency range (10 to 100 kHz), where there usually isn’t a lot of ambient noise. Well, unless there’s a high-frequency, multi-beamed echosounder in the vicinity.
Worse yet, no one knows how many of these noise machines are out there. Echosounders themselves are common equipment on the high seas, used by everyone from fisherman to oceanographers. But Exxon’s echosounder is far more dangerous than that fish finder on your uncle’s pontoon boat. The waves of sound it emitted were nearly as powerful as the Navy’s lower-frequency sonar systems.
Just last week, a phalanx of environmental groups (including NRDC) won a federal court case against the U.S. Navy that could help protect marine mammals off the Pacific Northwest. The ruling forces the National Marine Fisheries Service to reevaluate the impact of naval war exercises on wildlife—this time incorporating new scientific studies that were curiously overlooked when the agency issued permits to the Navy last year.
Meanwhile the bodies on the beach in Madagascar have made it clear that we can no longer ignore all the other types of racket we’re creating across this big, blue marble. Our underwater blips and bangs, whether high frequency or low, affect influence ocean life in ways we’re only beginning to grasp. And yet, Big Oil keeps on blasting.
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