NMFS: Apache Cook Inlet 3-D not a threat

Biological opinion from National Marine Fisheries Service finds planned program won’t jeopardize beluga whales or Steller sea lions

Kristen Nelson

Petroleum News

The National Marine Fisheries Service Alaska Region has issued a biological opinion on Apache Alaska Corp.’s proposed Cook Inlet 3-D seismic program, concluding that it “is not likely to jeopardize the continued existence of the Cook Inlet beluga whale or Steller sea lion populations, nor to destroy or adversely modify Cook Inlet beluga whale critical habitat.”

Apache has acquired more than 800,000 acres of oil and gas leases in the Cook Inlet basin and is planning a 3-D seismic survey program to determine if and where any viable oil fields are located.

The company conducted a seismic test program in the spring of 2011 to evaluate the feasibility of using new nodal seismic recording equipment in the Cook Inlet environment, found the nodal (no cables) technology feasible and is proposing a three-year program.

NMFS said results from a sound verification study conducted last September in Cook Inlet found that noise from onshore activity does not transmit into Cook Inlet waters at levels exceeding the agency’s acoustic harassment threshold for intermittent sounds, so the agency evaluated only intertidal and offshore areas in the biological opinion.

The first offshore and transition zone surveys are planned to begin in mid-April 2012.

NMFS said Apache has committed to not conduct seismic activities in areas which could impact beluga whales in the Susitna Delta from mid-April through mid-October, the peak usage of the area by beluga whales for foraging and possibly for breeding activities.

During each 24-hour period, in-water airguns will only be active for approximately 2.5 hours during each slack tide; seismic operations will not be conducted in ebb and flood tides “because the signal-to-noise ration of the seismic data are extremely poor due to the high ambient noise from the tidal flow,” the agency said. With approximately four slack tide periods in 24 hours, Apache’s airgun operations will be active approximately 10-12 hours per day, weather permitting.

Mitigation measures

As Apache acquires other permits, such as a Marine Mammals Protection Act permit, NMFS said additional mitigation measures may be imposed.

Protected species observers will be used to alert vessels to the presence of marine mammals during seismic operations and prior to the start of airgun operations.

“When marine mammals are observed within or about to enter designated safety zones, airgun or pinger operations will be immediately powered down or shut down as necessary,” the agency said.

Apache will conduct aerial surveys when operating near river mouths prior to the first shot to ensure no beluga whale congregations, five or more whales, are present.

When possible the company will also employ shore-based monitors located on scaffolding of sufficient height to observe marine mammals and will use passive acoustic monitoring to enhance detection during both day and nighttime operations.

In ice-free conditions, passive acoustic monitoring will be located in both up-inlet and down-inlet directions and the monitoring should be able to detect whistles from animals just entering the exclusion zone and well into the zone.

The ramp-up procedures involve gradually increasing airgun volume to allow marine mammals in the area time to leave before full airgun array firing begins.

NMFS said while it expects that beluga whales will be “taken,” those takes are expected to be non-lethal and mostly due to harassment and disturbance by noise, and said it believes “it unlikely that non-injurious takes, such as intentional harassment due to noise, would elicit consequences to the survival or reproductive capacity of the Cook Inlet beluga whales.”

Steller sea lions only rarely occur in the area of the proposed seismic survey, the agency said, and there are no rookeries or haul outs in the area.