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NMFS issues proposed Apache seismic LOA Finds that planned offshore Cook Inlet seismic surveys will have negligible impacts on Beluga whales and other marine mammals Alan Bailey Petroleum News
The National Marine Fisheries Service has published for public review a proposed letter of authorization for the incidental take of marine mammals during Apache’s offshore seismic survey operations in Alaska’s Cook Inlet. The authorization covers the period from March 1, 2015, to Feb. 29, 2020. The Fisheries Service has found that the planned surveys will have negligible impacts on beluga whales, gray whales, harbor porpoises, harbor seals, killer whales and Steller sea lions, the six species of marine mammal that may be encountered in the inlet. The agency has also determined that the surveys will not adversely impact Native subsistence hunting in the region.
The Cook Inlet beluga whales and the western stock of Steller sea lions are listed as endangered under the Endangered Species Act.
Major seismic program Apache has been engaged in a major program of seismic surveying in the Cook Inlet basin, to identify potential targets for oil and gas exploration wells. In 2012 the company completed its first offshore survey in the northern part of the Cook Inlet. Apache spokeswoman Lisa Parker has told Petroleum News that in 2014 the company completed two more offshore surveys, one off the northwestern Kenai Peninsula and the other farther south, westward from Kalifonsky Beach to the Ninilchik section of the Kenai Peninsula coast.
The proposed letter of authorization for further surveying encompasses much of the upper Cook Inlet, covering a 1,863-square-mile area extending from just south of Kalgin Island, north to waters west of the northern Kenai Peninsula. And, rather than linking to plans for specific individual surveys, the authorization accommodates any survey that Apache may decide to carry out within the designated region during the five-year duration of the approval.
Authorization required To avoid infringing the Marine Mammals Protection Act, a company conducting offshore seismic surveys requires an authorization from the Fisheries Service for the unintended minor disturbance of marine mammals. Previously Apache has obtained this type of authorization for its Cook Inlet surveying by obtaining annual incidental harassment authorizations, a process that involves filing an application each year, with the application process involving a public review. The letter of authorization that the company has now applied for covers a five-year rather than a one-year period. The application process is longer and more complex than that for an incidental harassment authorization - it involves two public comment periods, for example. However, once the letter of authorization has been issued, no further public reviews are required.
Air guns used An offshore seismic survey of the type that Apache conducts in the Cook Inlet involves towing arrays of air guns behind two relatively small vessels, with the air guns being fired at regular intervals to create sound signals that reflect from subsurface geologic features before being recorded by recording nodes placed on the seafloor. A sound system called a pinger is used in precisely determining the locations of the recording nodes.
In its application for the letter of authorization Apache proposed several mitigation measures to avoid adverse impacts on wildlife. These measures include the cessation of air gun operations if any animals approach a disturbance exclusion zone around the air guns, and course alterations by the seismic vessel if an encounter with an animal appears imminent. During its seismic operations Apache conducts a marine mammal observation program from the seismic vessels, from onshore platforms and from the air, to spot animals that the survey operations may encounter.
Additional measures As part of its proposed authorization for Apache’s operations, the Fisheries Service requires some additional mitigation measures, including the imposition of an air gun exclusion zone within 10 miles of the mean high water line of the Susitna River delta area, on the west side of the inlet from April 15 to Oct. 15. The exclusion zone would protect a critical habitat area, important to beluga whales for feeding and calving, the Fisheries Service says. The Fisheries Service also requires Apache to suspend seismic operations within a specified distance of a marine mammal stranding, should a stranding occur.
Taking into account an analysis of the likely frequency of interactions between Cook Inlet marine mammals and Apache’s planned operations, and also considering factors such as the proposed mitigation measures, the Fisheries Service has concluded that the seismic surveys will only disturb small numbers of animals. The agency also says that during meetings between Apache and the Native communities of the Cook Inlet region, the communities did not raise any concerns about potential impacts on subsistence hunting.
The Fisheries Service requires comments on the proposed letter of authorization by March 25. The agency has set an identical public comment deadline for a draft environmental assessment for the authorization.
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