Who needs science when you can bluff your way to profits:
There has been no observation of direct physical injury or death to free-ranging fish caused by seismic survey activity, and there is no conclusive evidence showing long-term or permanent displacement of fish.
Seismic and other geophysical surveys are the first critical step to better understanding the nation’s resource potential and there is not one single verifiable instance of sound from these surveys harming marine life populations. We cannot afford to put the nation’s energy security and independence at risk by limiting access to safe affordable domestic energy because of the baseless accusations of environmental activists. The economic and energy future of the United States is far too important to cater to the short-sighted agenda of a few.
Bolding mine. Of course the drilling part comes after the seismic surveys, I just couldn't let that "safe affordable domestic energy" BS leak into the discussion without pointing out the fallacy. The Deepwater Horizon spill alone cost billions in cleanup and lost revenues, not to mention actual lives. Combine that with the countless other spills and leaks, and the words "safe" and "affordable" should be excluded from any reference to offshore drilling. Back to the seismic testing and sea life issues:
Displacement by a continually operating seismic vessel in a key habitat type could have much more profound and serious effects on individual animals and the population than exposure for animals migrating or not in a key habitat type. For example Exmouth Gulf is used as a resting area by southerly travelling humpback whales, specifically by cows resting and feeding 4–8-week-old calves. At this stage of their lives the calves are small, comparatively weak and possibly vulnerable to predation and exhaustion. The potential continual dislocation of these animals in a confined area would interrupt this
resting and feeding stage, with potentially more serious consequences than any localised avoidance response to an operating seismic vessel as seen during their migratory swimming behaviour. Similarly any repetitive displacement or disruption of animals on their calving grounds during the time when they are present (e.g. southern Kimberleys for Western Australian humpbacks during July to late September), may have serious consequences at the population level.
It's an in-depth study, utilizing both actual airgun testing near whales (and other creatures) and computer modeling. The far-ranging migratory whales seem to be the least affected (first to recover), except in the instances where single males are actually attracted to the airguns, and may have trouble catching up with potential mates after the distraction. But the smaller the range, the worse the disruption:
The same could not be said for humpback whales which are not migrating, but which are relatively sedentary in an area and involved in some behavioural activity which is important from a population perspective (key habitats). For humpback whales along the Western Australian coast such areas include at least: the southern Kimberleys between Broome and the northern end of Camden Sound; Exmouth Gulf; Shark Bay; waters to the north and northeast of Rottnest Island; and Geographe Bay, during the late winter-spring months. In particular C and M-N Jenner have identified the southern Kimberley
region as a calving ground used by a large portion of the Western Australian humpback whale population.
In these key habitat areas the possibly lower threshold for response to air gun signals could be expected to result in displacement by an operating seismic survey vessel at ranges greater than observed for animals outside these habitat types.
Any displacement or disruption in a calving ground can have horrific results, exposing the young (even more) to predators like sharks and orcas. But the industry would have us believe that's just nature taking its course. Their avoidance of responsibility for secondary effects like this reveals not only their bias but also their selective use of science. Same goes on land as it does in the oceans. And it's not only whales who are at risk, sea turtles and cephalopods:
Lenhardt (1994) reported on a swimming response from loggerhead turtles in large shallow tanks on presentation of low frequency tones. Although the results are not directly applicable to impulsive air gun signals they suggest that the increase in swimming behaviour seen in our trials and by Lenhardt (1994) may be a generic sea turtle ‘alarm’ response.
The available evidence from these trials and the literature suggests that sea-turtles may begin to show behavioural responses to an approaching air gun array at a received level around 166 dB re 1
μ Pa rms and avoidance around 175 dB re 1 μ Pa rms. From measurements of a seismic vessel operating 3D air gun arrays in 100–120 m water depth this corresponds to behavioural changes at
around 2 km and avoidance around 1 km.
Three trials were carried out with caged squid (Sepioteuthis australis) to gauge their response to nearby air gun operations. In the first trial several squid showed a strong startle response to a nearby air gun starting up by firing their ink sacs and/or jetting directly away from the air gun source at a received level of 174 dB re 1 μ Pa rms. Throughout this trial the squid showed avoidance of the air gun by keeping close to the water surface at the cage end furthest from the air gun. The air gun level never fell below 174 dB re 1 μ Pa rms throughout this trial. During two trials with squid and using a ramped approach depart air gun signal (rather than a sudden nearby startup), the strong startle response was not seen but a noticeable increase in alarm responses were seen once the air gun level exceeded 156–161 dB re 1 μ Pa rms.
Just a final note, for those who would speculate as to the motivations of those who performed this research and evaluation: The bulk of this study was funded by the oil & gas industry itself. Let that sink in. These people are well aware of the dangers associated with seismic testing, and they not only push for more access, they create propaganda that is in direct conflict with their own research. Because profits.