Man-made noise in the ocean and bowhead whale reactions

Centuries of refinement of Inupiat TEK has led to modifications during the bowhead hunt to maintain low noise levels on the ice. Whalers noticed whales were deflected by boats, planes and snowmachines. Whaling captains in the 1980's told our biologists that noise from airguns used during seismic testing and other ship noise deflects whales and makes them 'skittish' and hard to hunt. Scientific studies, at the time, indicated only minor reactions by whales. However, in areas near seismic activity, the whaling crews had to go out much further to hunt, which is more dangerous. Later studies verified the reactions of bowheads to underwater sound, including deflection, changes in dive behavior, and changes in blow intervals. This information has led to mitigation measures [required] of industry and research activities to allow "quiet periods" for the bowhead subsistence hunt. Ship, seismic, and industrial noise is now regulated through the CAA (Conflict Avoidance Agreement with the AEWC) to avoid unnecessary noise during the periods of the fall bowhead hunt.

Documentation of TEK:

Richardson, W.J et al. 1995. Marine mammals and noise. Academic Press, San Diego, CA.

Richardson, W.J. (ed.) 2000. Marine mammal and acoustical monitoring of Western Geophysical’s open-water seismic program in the Alaskan Beaufort Sea, 1998.  LGL Rep. TA 2313-4. King City, Ont., Canada: LGL, Ltd., Environmental Research Associates, 155pp.

Richardson, J. and Thomson, D. (eds.) 2002. Bowhead whale feeding in the Eastern Alaska Beaufort Sea: update of scientific and traditional information.  OCS Study MMS 2002-012; LGL Rep. TA 2196-7. Rep. From LGL Ltd., King City, Ont., for U.S. Minerals Management Service, Anchorage, AK, and Herndon, VA. Vol. 1, xliv + 420 p; Vol. 2; 277 p.

These graphs, from an intensive research project, confirm the TEK on noise disturbance of migrating bowhead whales. The pink star is the position of the seismic vessel and the circle provides a 20 km radius reference. The top graph shows the positions of whales relative to the seismic vessel when airguns were operating and the lower graph whale positions without airgun activity. Note the very different distributions of the whale sightings. (Richardson et al., 1999)

These graphs, from an intensive research project, confirm the TEK on noise disturbance of migrating bowhead whales. The pink star is the position of the seismic vessel and the circle provides a 20 km radius reference. The top graph shows the positions of whales relative to the seismic vessel when airguns were operating and the lower graph whale positions without airgun activity. Note the very different distributions of the whale sightings. (Richardson et al., 1999)

Richardson, W.J. (ed.) 1999.; Marine mammal and acoustical monitoring of Western Geophysical’s open-water seismic program in the Alaskan Beaufort Sea, 1998.  LGL Rep. TA2230-3. Rep. from LGL Ltd., King City, Ont., and Greenridge Sciences Inc., Santa Barbara, CA, for Western Geophysical, Huston, TX, and National Marine Fisheries Service, Anchorage, AK, and Silver Spring, MD; 390 p.

For more information on bowhead whales and sound, go to this page.

Sense of Smell in Bowheads

Inupiat whalers have long told NSB scientists that “bowheads can smell” and are sensitive to smoke and odors. Some of the traditional practices that have been passed down for generations supported this idea, including the fact that burning was not allowed on the ice during whaling, and latrines were set up the lead on the ice so whales would not be deflected before they reached camp.

Scientific studies suggested that there was no sense of smell in whales. Studies indicated that there were no structures associated with the sense of smell (like olfactory bulbs or olfactory tracts) in odontocetes (or toothed whales) like beluga. It was assumed that there was no olfaction in mysticetes (or baleen whales) like bowheads either.

In the fall of 2008, Hans Thewissen was in Barrow conducting research on bowhead hearing. He asked NSB and the AEWC for permission to look at the entire brain and the brain cavity of a bowhead whale. While looking at the brain, he noticed that there were tissues that looked like olfactory bulbs connected in the back to the brain and in the front to the lining of the nasal passages (near the blowhole area).

Further testing in the lab confirmed that these tissues were functional which means that bowhead whales do indeed have a sense of smell, once again confirming the TEK from whaling captains.

Why do bowheads have a sense of smell? That is yet to be confirmed, but it would likely have to do with locating their prey, such as krill. Smell receptors must come in contact with airborn "smells" and bowhead whales could "smell" the air when they surface.

HThewissen
Hans Thewissen in his lab at NEOUCOM (Northeastern Ohio Universities Colleges of Medicine and Pharmacy).The skeleton on the shelf is an example of an early "walking whale" fossil Thewissen found in Pakistan, called Pakicetus. Photo credit: Hans Thewissen

Documentation of TEK:

Thewissen, H. et al. 2011. Olfaction and brain size in the bowhead whale (Balaena mysticetus). Marine Mammal Science, in press.

Read this article for more on the story of bowhead sense of smell and Dr. Thewissen.

Walker, M. 2010. Whale 'sense of smell' revealed. BBC Earth News. This article discusses the importance of this discovery of olfaction (or sense of smell) in bowhead whales.

 

Banner photo credit: Carin Ashjian