The True Cost of Seismic Surveys

As Interior Secretary Ken Salazar barnstorms across America to solicit public feedback on offshore energy development, one question routinely asked at the hearings is whether or not we have enough data on our offshore oil and gas resources to make important leasing decisions. After all, the offshore areas that until recently were protected from oil and gas drilling have not seen serious exploration for 25 years.

According to Reuters, the Interior Department is considering paying private companies about $1 billion to collect seismic data off our coasts because, as Secretary Salazar stated, "I don't know how you can make honest thoughtful decisions, whether it is to develop or not to develop (offshore supplies) without having the best science on the table."

We agree with Secretary Salazar:  better scientific data will be crucial to understanding the resources available in the Outer Continental Shelf and the impacts of accessing them. (See NRDC comments to Mineral Management Service regarding OCS seismic activity).  But it's important to note that the seismic testing under consideration is by no means benign.  The evidence is clear that seismic testing is very harmful - even deadly - to fish and marine mammals.  And not included in the billion dollar seismic price tag is the cost to marine wildlife.

To carry out seismic surveys, ships tow multiple airgun arrays that fire shots of compressed air into the water; the echo back tells us about the geological conditions below the seafloor (including favorable conditions for oil and gas).  Airguns blast high intensity pulses about every 10 seconds for the length of the survey - which can last days or weeks at a time. These high-intensity pulses can kill, injure and disturb a wide range of marine wildlife and can affect species on a vast scale:

  • Fin whales, an endangered species, have been shown to fall completely silent over at least a 10,000 square mile area around a single seismic array, making it impossible for them to forage or breed.
  • Beaked, humpback, and melonheaded whales were found stranded on beaches in the Gulf of California, (Mexico), Abrolhos Banks (Brazil), and the coast of Madagascar while surveys were conducted nearby.
  • Bowhead whales have altered their migration by over 30 kilometers to avoid seismic surveys, and harbor porpoises have been found fleeing seismic arrays from 80 kilometers away.
  • Western Pacific gray whales, a critically endangered population, abandoned important feeding grounds in response to seismic surveys. 
  • Catch rates of cod and haddock have been shown to plummet over a 5,000 square mile area around a single seismic array, and similar findings have been in seen in rockfish and other species. 
  • The inner ears of pink snapper were permanently damaged from seismic airguns.
  • Mass strandings of giant squid have been linked to seismic surveys. 

The Interior Department's recent report - Survey of Available Data on OCS Resources and Identification of Data Gaps - acknowledges the serious impacts that anthropogenic sound - including the intense sound generated from seismic surveys - can have on marine mammals and fish, but it does not suggest specific measures to lessen those impacts.   

Before proceeding any further, we need to be sure that we are gathering new data in a way that does not extract undue costs on marine wildlife:

  1. Seismic testing should only go forward after adequate baseline data on the living marine environment is collected.  Does the cost to the marine life and the uses that rely on those resources outweigh the benefits from oil and gas development? Simply avoiding important ecological areas - such as key breeding, feeding, and migratory habitat - is the best way to lessen the enormous costs of seismic testing on marine wildlife.  Let's be sure we know enough before subjecting these marine systems to harm. (Read about the studies NRDC is asking for.)
  2. Seismic testing should only go forward with strong mitigation measures, including, at a minimum: 
  • Requiring robust safety zones around the array, to reduce the risk of injury to marine mammals and other species
  • Implementing other operational restrictions (such as routing airguns to ensure that marine mammals are not driven ashore)
  • Maintaining safety zones through visual and passive acoustic monitoring
  • Limiting periods of exposure
  • Requiring use of alternative technologies and engineering modifications, such as baffling to eliminate unneeded higher-frequency output from the array
  • Considering oceanographic effects such as bathymetry and currents (to take account of variations in acoustic propagation between locations), and
  • Establishing an independent, publicly inclusive committee to review relevant environmental management practices.

Marine wildlife pays a huge price for seismic surveys - we owe it to ourselves to do everything to reduce those costs by positively ensuring that the ends actually do justify the means.