A sperm whale blowing as it rests at the surface. (Photo by Bill Lang, National Science Foundation, (formerly of MMS))

It took US $9.3 million, a team of researchers, and some very patient sperm whales, but the verdict is in – airgun sources do not seem to upset these giant creatures or disturb their hunting patterns.

That was the news from a press conference held by the US Minerals Management Service (MMS) Thursday at the Wiess Energy Hall at the Houston Museum of Natural Science. MMS brass was joined by two of the scientists involved in the study, Doug Biggs from Texas A&M University and Bruce Mates from Oregon State University, to discuss the results of the multi-year study.

The study, titled “Sperm Whale Seismic Study in the Gulf of Mexico,” was conducted by MMS with cooperation from the Office of Naval Research, the National Science Foundation, and the National Fish and Wildlife Foundation. Eight universities were involved, with Biggs and colleague Ann Jochens serving as principal investigators.

Since sperm whales rely on acoustics to find their prey, and since they are the only endangered species in the Gulf of Mexico, they were an obvious choice for the study, although it’s been suggested that other species might also be affected by seismic surveys. Whales in the study were tagged two ways. One was a short-term tag used to analyze the animals’ behavior before, during, and after airguns were deployed in the area. The other was a long-term tag used to track their migration patterns over the course of several months or years. Of particular interest was the movement of the whales while airguns were being deployed. While the number of subjects was limited, only one of the tagged whales showed any inclination to move away from the source of the noise.

The results of the longer term study represent some of the most comprehensive research ever undertaken on these creatures. Among their findings, researchers determined that the estimated population of sperm whales in the Gulf is somewhere between 500 and 1,500. They show genetic and social differences from other sperm whales around the world, a fact uncovered because the clicking sounds that the whales make are different from those made by sperm whales in other regions. This is perhaps not surprising since, during the course of the study, only one whale actually left the Gulf of Mexico (he returned after 2-1/2 months). Many of the whales tagged belong to family groups of females and maturing young that tend to travel less than the males.

“The five-year study has greatly contributed to our knowledge of sperm whales, especially those found in the Gulf of Mexico,” Biggs said. “It’s also raised new questions we need to know more about, such as their feeding and breeding patterns. There’s still a lot we don’t know about these huge creatures.”

While the whales typically seemed unconcerned about seismic boats in the region, new rules have been enacted. It is now required that seismic contractors have a visual spotter on each vessel, and if whales are seen within 1,640 ft (500 m) of the vessel, operations are to be shut down until the animals leave the vicinity. Although other marine mammals and sea turtles have not been studied as extensively, these rules apply to them as well. Biggs said that so far these “best practices” have shown to have a significant effect on the industry’s ability to co-exist with the creatures that live in the Gulf.