A U.S. Department of the Navy final supplemental environmental impact statement for the Gulf of Alaska released Friday shows a potential for impacts to marine mammals during training activities. The study is available for public review until Aug. 29.
The study analyzes three scenarios. The first sees no changes from types or levels of training occurring prior to 2011.
An alternative shows increased training levels, a large-scale carrier strike group exercise, use of active sonar for up to 21 consecutive days from April through October, training on new weapons, technology and machinery, and use of an underwater tracking range.
A second alternative adds a second large-scale carrier strike group exercise during the summer and one sinking exercise to the first alternative.
The study found that all three of the scenarios studied result in at least level B harassment for marine mammals from use of explosives. According to the National Marine Fisheries Service, level B harassment is defined as an action that has the potential to disturb behavioral patterns.
In the third scenario, the explosives could result in level A harassment. The NMFS defines level A harassment as an activity with the potential to injure or kill the mammal.
The use of sonar in the two alternative scenarios would also lead to both level A and level B harassment of marine mammals.
However, the EIS states that the scenarios “would contribute to cumulative impacts, but the relative contribution to overall cumulative impacts would be small compared to other human actions, such as commercial ship strikes, bycatch, entanglement, and ocean pollution.”
Mitigation efforts addressing the potential impact on marine life include the establishment of a cautionary area for whales from June through September and limiting or stopping certain activities within habitat areas of particular concern indicated by NMFS, according to the EIS.
The report indicates that “the best available science indicated that training activities will not compromise the productivity of fish or affect their habitat. Additionally, it was reemphasized that fishermen will also see little to no change.”
The release “follows years of research, analysis, public involvement, tribal consultations with 13 Alaska Native federally recognized tribes, and regulatory consultations with the National Marine Fisheries Service,” Navy Region Northwest public affairs deputy Sheila Murray said in an email.
According to the report, the study was conducted because new information and analytical methods has emerged since the last study was completed in 2011 and because the latest Marine Mammal Protection Act letter of authorization from the National Marine Fisheries Service expired on May 4.
According to the statement, no new or increased training activities are being proposed that were not a part of the 2011 EIS.
The final supplemental EIS can be reviewed online at goaeis.com.