Posts Tagged ‘sonar’

Navy touts its own horn for sonar testing and marine mammal takes

Wednesday, February 3rd, 2010

Last month, the Navy received reauthorization for three of its marine mammal “incidental take” permits under the Marine Mammal Protection Act (MMPA) and Endangered Species Act (ESA). Basically, these are permits to harass marine mammals for specific purposes allowable under the MMPA and ESA. Before you get your britches in a knot, you need to realize that ALL marine mammal researchers are required to obtain such authorizations when attempting to closely approach their subjects. I worked under one, my friends worked under them, and—for the most part—execution and enforcement of the terms of such permits are strictly adhered to.

According to yesterday’s press release from the Navy, their reauthorizations of the so-called "Big Three" represent ocean sites where "roughly 80 percent of active sonar training … takes place on established training ranges and operating areas." Now, here’s the part where you can get knotted. The Navy refers to this action (the reauthorization of their incidental take permits) as "an environmental accomplishment."

Hmm. The last time I checked, an environmental accomplishment was a positive action taken on behalf of our abiotic and biotic surroundings. Seeing the government’s approval of sonar testing as a positive action on behalf of the environment is quite the stretch, oh Naval colleagues. Not that there’s anything wrong with that. The Navy gets a lot of bad press when it comes to its testing of low- and mid-frequency sonar and its effects on marine mammals. So we can’t really blame them for spinning this dubious news in a positive light. Let’s just hope that they keep up the accurate reporting of marine mammal injuries and other “takes” during their testing exercises.

whale tail

Stock photo by Jon Sullivan

  • Share/Bookmark

NOAA pushes Navy to stop sonar testing at marine mammal hot spots

Saturday, January 30th, 2010

The National Oceanic and Atmospheric Administration (NOAA) has acknowledged the link between certain types of sonar and negative impacts on marine mammals, including death. In an letter to the Council on Environmental Quality last week, NOAA Administrator Jane Lubchenco proposed that marine mammal "hot spots"—areas where marine mammals are in high abundance—become off limits to mid-frequency active sonar testing. (Lubchenco is, by the way, the first woman AND the first marine ecologist to lead NOAA. Huzzah!)

According to this LA Times blog post, NOAA is also calling for a process to estimate the "comprehensive sound budget for the oceans." This is a huge step in developing a plan to protect marine species that rely on underwater communication. It’s critical, too, in light of the new findings that link ocean acidification with the decreased transmission of underwater sound (see this recent post.)

The letter from Lubchenco to the CEQ is available here (PDF).

  • Share/Bookmark

Sonar and strandings

Monday, December 28th, 2009

by Hilary L. Maybaum

Why do mass strandings of marine mammals happen? Researchers have been trying to answer this question scientifically for decades. Various hypotheses have been put forth, from parasitic diseases to anomalies in Earth’s magnetic field. Now, manmade sonar can be added to that list.

Sonar—an acronym for SOund Navigation And Ranging—is the technique of using sound propagation to navigate, communicate, or detect underwater objects. Originally deployed on a massive scale during World War I for enemy submarine detection, sonar has since become a mainstream navigation and fish-finding aid for military, commercial, and recreational vessels alike. It relies on variations in underwater sound speed, determined mainly by temperature, pressure, and salinity (saltiness). There are two kinds of sonar systems. Passive sonar simply “listens,” without transmitting any sound. Active sonar—such as that used in fish-finding—emits sound pulses, sometimes called pings, for detection of objects. The pulses can vary in frequency, loudness, and duration.

I actually did my Master’s Thesis on the effects of an active 3.3 kHz sonar systems on humpback whales in Hawaii. A group of sonar engineers in Massachusetts had a National Geographic grant to test a prototype system on its detection of humpback whales in Stellwagon Bank. They were getting lousy results, mostly because of the shallowness and sound opacity in the bank’s waters. I invited them to come test their system in Hawaii, where the waters were clear and deep. They did, and I investigated the behavioral effects of their system on the whales. It turned out there were some observable effects, and we all concluded it was not a plausible system to use for this purpose.

But I digress. This post is about beaked whales.

Cuvier's beaked whale

Public domain image of a Cuvier's beaked whale from the National Oceanic and Atmospheric Administration

In 2005, a group of scientists studied a mass stranding of beaked whales off the Canary Islands and found lesions apparently induced by mid-frequency sonar sounds. Previously, other scientists had suggested a link between mass stranding of beaked whales and mid-frequency sonar, but were unable to establish a causal relationship. This particular stranding event of 14 whales occurred about four hours after the onset of an international naval sonar exercise conducted between the coast of Fuerteventura Island and 40 km offshore.

Postmortem examinations of the whales found no external trauma or bruising, with the exception of one postmortem shark bite. No pre-existing health issues were indicated. The researchers did, however, find severe internal hemorrhaging, swelling, and congestion in the head and neck areas, including the jaws, ears, and brain. They also found evidence of nitrogen supersaturation (“the bends”) in the blood vessels and tissues of vital organs. Beaked whales are known for their deep diving capabilities, and don’t normally get the bends unless their dive behavior is dramatically altered (see this press release from Peter Tyack’s group at the Woods Hole Oceanographic Institution).

The Natural Resources Defense Council (NRDC) sued the Navy over the use of mid-frequency sonar after this and similar findings were published. I’m interested in finding out where that lawsuit stands.

Update: The lawsuit was settled this time last year, in favor of the Navy. A precedent had already been set by the Supreme Court. According to a 12/29/08 NY Times article:

…in a ruling on a council lawsuit challenging the Navy’s sonar training exercises off Southern California, the Supreme Court ruled that military training trumped protecting whales.

Chief Justice Roberts wrote that forcing the Navy to deploy an inadequately trained antisubmarine fleet would jeopardize the safety of the fleet. He also wrote that it was unclear how many marine mammals the Navy’s sonar exercises might harm.

Many thanks to Dr. Joseph Mobley for sending me the original article on the mass stranding event from Vet Pathol 42:446-457 (2005).

Thanks also to Mary Beckman (@sciwriter) for the update on the Navy’s lawsuit.

  • Share/Bookmark