Final Environmental Assessment/Analysis of Marine Geophysical Surveys by R/V Marcus G. Langseth off North Carolina, Northwest Atlantic Ocean

Lamont-Doherty Earth Observatory (L-DEO) plans to conduct a high-energy 2-D survey at the Cape Fear submarine slide complex off North Carolina from the R/V Langseth during Spring/Summer 2023. The 2-D survey would occur within the Exclusive Economic Zone of the United States and in International Waters, in waters depths ranging from 200 to 5,500 m deep. The survey would use an 18-airgun array consisting of 40-360 in3 GI guns, with a total discharge volume of 3,300 in3. Approximately 6083 km of transect lines would be surveyed in the study area. The survey is expected to last for 33 days, with approximately 28 days of seismic operations, 3 days of piston coring and heat flow measurements, and 2 days of trains. This IHA would be valid for one year from the date of issuance. L-DEO’s requested is for the take of 30 species of marine mammals by Level B harassment and, for 2 of these species, by Level A harassment. No mortality or serious injury is anticipated nor is any proposed for authorization.
There was no public or NGO concern with this action during the 30 day comment period for the proposed IHA. Although this action involves the use of seismic airguns in a region where North Atlantic right whales could occur, the additional requirements in the IHA reduce the potential impact on this species. The survey is not expected to result in serious injury or mortality of any marine mammals. There is no known congressional interest in this particular action.