Shipping noise correlated to stress in whales

A recent paper in the Proceedings of the Royal Society correlates shipping noise with stress levels in baleen whales. Heretofore this has been a difficult assumption to prove because we do not have any baseline of whale stress levels prior to the introduction of the vast shipping networks we now use in global trade.

Map of shipping routes

Researchers can get an idea of metabolic stress levels because they are correlated to hormone indicators (glucocorticoids) in body fluids. Rosalind Rolland with the New England Aquarium was studying the glucocorticoids in the feces of North Atlantic Right whale in the Bay of Fundy through September 2001. She was doing this research concurrently with a study on Right whale social behavior being conducted by Susan Parks with Penn State and Syracuse University.

Both of these studies overlapped the September 11 tragedy and the subsequent halting of air and sea transportation for a few days. It was across this time that the noise levels in the ocean decreased significantly. Parks, Rolland and other colleagues brought their work together and noticed a marked decrease in stress indicators with the decrease in shipping noise.

Whale Feces Sniffing Dog

This is a real benchmark to our understanding of how chronic anthropogenic noise impacts baleen whales – which are too large to test in lab settings and not really interested in cooperating with behavioral scientists in the wild. Given that the glucocorticoids are part of a feedback mechanism in the immune system, this finding also confirms concerns that shipping noise compromises the health of these whales.

The paper is discussed in “lay” terms in a Science article that also introduces us to the critically important scientific instrument, a dog – whose nose can pinpoint whale feces in the ocean. (The dog was not included as a co-author on the paper.)

This paper should provide us with important supporting data as we attempt to slow industrial development in the pristine acoustic environment of Arctic.

Report from the May 2009 Acoustics Society meeting

Density of two months of large commercial vessel traffic in the sanctuary, with peak densities seen in the shipping lanes

Density of two months of large commercial vessel traffic in the sanctuary, with peak densities seen in the shipping lanes

“Thrilling” is not a word I thought I would ever use in describing an Acoustical Society meeting, but there were moments last week that bordered on just that. Driving this is an intersection of rapidly increasing computer processing power and advancing sensor technologies – put in the hands of some of the nimble intellects that are making up the current crop of bio-acoustic post-docs.

Over the five days of the meeting there were many sessions on “Passive Acoustic Monitoring” (PAM) which presented many of the aspects of putting sensors in the ocean, collecting the data, and then making sense of it all. In practice this often means collecting the vocalizations of whales or dolphins over a period of time and watching the population dynamics change as a consequence of environmental conditions.

The output of these studies can be time-compressed animations of the peregrinations of dolphin schools or whale pods,[i] or in the case of Chris Clark, the acoustical impacts of ship traffic on humpback, fin and right whales.[ii] Dr. Clark’s animated display was a stunning “spatial-temporal” graphic of the changes in the hearing and communication range of these three whale species as a cargo ship passed over their habitat. I will make these graphics available on the OCR website once I get them from Chris, but meanwhile you can find out about the program here:

Another telling presentation by Manolo Costellote came from his PAM study of the seasonal migration of fin whales in the Mediterranean Sea over a three year period. During one of the seasons there happened to be a concurrent seismic airgun survey. The monitoring clearly demonstrated that the whales avoided their traditional winter feeding areas throughout and even after the survey. This indicates the acoustical impacts of airgun surveys reach over hundreds of kilometers for these animals.

Of course Manolo wanted to know where the surveys were taking place, and something about the sizes of the airgun arrays. He managed to locate the company doing the work, but they were predictably uncooperative. Not to be discouraged, he did a little sleuth work and found a “blog” of one of the crew members, which included the entire equipment list; airgun capacities, photographs of the ship, and pretty much everything he needed to calibrate his findings except for the exact locations of the survey (which he derived through some clever data evaluation).

It is work like this which may eventually put the current practices of airgun surveys “on the ropes” until the oil industry can find more benign ways of locating offshore oil.

Many other breakthroughs were presented and new ideas introduced over the course of the week across the field of acoustics. While overall the meeting was still pretty high on the “pencil-pocket” index, our field of marine bioacoustics is going through a thrilling sea change.

Stay tuned!

[i] Kaitlin E. Frasier “Acoustic tracking of whistling dolphins offshore of Southern California”

[ii] Christopher W. Clark “Result ad insights from operational monitoring networks”

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