Editor’s Note: CRE, in its role as a regulatory watchdog, routinely comments on the comments sent to regulatory agencies. These expost analyses are posted on this Interactive Public Docket (IPD) and the public and all stakeholders are invited to offer their comments. A copy of this post has been forwarded to NMFS.
The four leading trade associations of the petroleum industry the American Petroleum Institute, the Independent Petroleum Association of America, the International Association of Geophysical Contractors, and the National Ocean Industries Association responded to a proposal to list sperm whales as distinct population segment.
The industry response is precise, complete and well reasoned.
Highlights of the response include:
“Sperm whales in the GoM are not markedly separate from species in the Atlantic, Caribbean, or elsewhere. WEG’s petition offers no credible genetic, biological, physiological, behavioral, ecological, or regulatory evidence to demonstrate separation – much less marked separation. To the contrary, the evidence cited here demonstrate the existence of a single undivided genetic population of sperm whales from the GoM to northern Europe, if not beyond. (p. 3)
“In 1996, NMFS and FWS established a new, more encompassing DPS policy that, like the ESU policy and consistent with congressional intent, maintained a high bar to designate a DPS.56 For a population segment to be considered a DPS under the 1996 Policy, the segment must meet two criteria: (1) it must be discrete; and, (2) it must be significant.57 Discreteness requires conspicuous separation from the remainder of the species, but separation alone is not enough to be a DPS.58 Even if the species is markedly discrete, the listing agencies, at Congress’s direction, instruct that the discrete segment be significant in some unique biological manner or that the segment provide some significant role in the species as a whole.59 The “significance” element of the DPS Policy is critical to the evaluation of population segments for DPS status. Indeed, the listing agencies have found several populations to be distinct, but declined to extend DPS status because the discrete segment was not significant.” (p. 13)
See the industry response below.
The aforementioned comments complement CRE comments made on the same petition:
In fact, NMFS recently explained
“There is no specific evidence that exposure to pulses of airgun sound can cause PTS in any marine mammal, even with large arrays of airguns.”
“To date, there is no evidence that serious injury, death, or stranding by marine mammals can occur from exposure to airgun pulses, even in the case of large airgun arrays.” (p. 5 )
CRE concluded that a DPS Listing for GOM sperm whales based on the current record would be premature and would not meet Information Quality Guidelines
Sperm Whale: Industry Comments
In reference to Sperm Whales. One of the arguments in the recent GoM Sperm Whale petition is the potential adverse reaction sperm whales may have to man-made sounds. The authors, WildEarth Guardians in Denver Colorado, do not mention the body of scientific peer-reviewed literature on how toothed whales are able to decrease their own hearing sensitivity (e.g.: Nachtigall, P.E., Supin, A.Ya. (2008) A false killer whale adjusts its hearing when it echolocates. Journal or Experimental Biology v. 211, p.1714-1718., and references therein).
This was broadly publicized by reporter William J. Broad in the New York Times on July 17, 2012 (“Whales Show Signs of Coping with Loud Noises”) based on research performed at the University of Hawaii. Excerpt: “Scientists there are studying how dolphins and toothed whales hear. In nature, the mammals emit sounds and listen for returning echoes in a sensory behavior known as echolocation. In captivity, scientists taught the creatures to wear suction-cup electrodes, which revealed the patterns of brainwaves involved in hearing. The discovery came in steps. First, Dr. Nachtigall and his team found the animals could adjust their hearing in response to their own sounds of echolocation, mainly sharp clicks. The scientists then wondered if the animals could also protect their ears from incoming blasts”.
“Carl Safina, president of the Blue Ocean Institute, a conservation group in Cold Spring Harbor, N.Y., called the discovery a potential window into what sea mammals may already do on some occasions to protect their hearing. “I’ve sometimes wondered why high intensity sounds don’t cause problems all the time,” he said in an interview. “Maybe it’s that, once the animals hear something very loud, they can adjust their hearing — dial it down and protect themselves.”
(Blue Ocean Institute works to create a more knowledgeable constituency for conservation. It is led by conservation pioneer and MacArthur fellow, Dr. Carl Safina).
In response to GTH:
Some marine mammals produce loud sounds. A very basic question about marine mammal hearing is whether that hearing is protected during the loud echolocation emissions. It was a big question back when Don Griffin (1958) proposed the idea of echolocation in bats because no one believed that a bat would hear those very quiet echoes after emitting those loud calls. Suga & Jen (1974) showed that there was a nerve connection so that when a little brown bat Myotis lucifugus made an echolocation call it also sent a nerve message to its middle ear stapaedial muscle blocking hearing for about 8 ms during the call by 25 dB. So, the stapaedial reflex works to protect hearing when loud outgoing signals are produced by the animal. The same thing has been called the acoustic reflex in humans and it works, though not as efficiently, in people. If you make a loud sound, your stapaedial muscles will tighten the three small bones in your middle ear and your hearing will also be protected.
Sperm Whales make very powerful sounds when they echolocate. They are comparable to rifle shots (Mohl et al., 2003) exceeding 235 dB peak to peak. Bottlenosed dolphins also make intense echolocation clicks measured at greater than 230 dB peak to peak (Au, 1980). The basic question is: do the odontocete echolocators also have some sort of built-in ear protection during echolocation?
Literature Cited
Au, W.W.L.,1980, Echolocation signals of the atlantic bottlenose dolphin (Tursiops truncatus) in open waters. In Animal Sonar Systems (Ed R-G Busnel and J.F. Fish) New York: Plenum
Griffin, D.R., 1958, Listening in the Dark. Yale University Press, New Haven Ct.
Møhl. B., Wahlberg, M., Madsen, P. T., Heerfordt, A., and Lund, A., 2003, The monopulsed nature of sperm whale clicks. Journal of the Acoustical Society of America, volume 114, pages 1143-1154.
Suga, N. and Jen, Philip, H.-S., 1975, Peripheral control of acoustic signals in the auditory systems of echolocating bats. Journal of Experimental Biology, volume 62, pages 277-311.