Chapter VI — Effects of Pollution 



not increase over time, and (2) monitoring programs 

 adequate to verify that neither the target marine 

 mammals nor any non-target species are affected 

 adversely. Actions taken by the National Marine 

 Fisheries Service to incorporate and assess the effec- 

 tiveness of pingers in the management regime for 

 gillnet fisheries in the northeastern United States are 

 described in the Gulf of Maine harbor porpoise 

 section of Chapter II. 



The workshop report also noted that high-intensity 

 sound generators — referred to as acoustic harassment 

 devices or AHDs — were being used in the United 

 States and elsewhere to try to keep seals and sea lions 

 away from salmon aquaculture facilities. It pointed 

 out that these devices appear to work because they 

 produce sounds that are painful or frightening to 

 pinnipeds. It also pointed out that it is not known 

 whether seals and sea lions will approach these 

 devices close enough to have their hearing temporarily 

 or permanently damaged or whether the sound pro- 

 duced by the devices will affect other species adverse- 

 ly. With respect to the latter point, it was noted that 

 there were unpublished reports of harbor porpoises 

 apparently responding to sounds produced by AHDs 

 at distances in excess of 1 km (0.62 mile). Because 

 of such uncertainties, the workshop participants 

 concluded that (a) use of high-intensity AHDs should 

 be considered only when other less aversive measures 

 {e.g. , locating fish farms as far away as possible from 

 pinniped rookeries and constructing physical barriers 

 to keep seals and sea lions out of fish pens) have been 

 tried and found to be inadequate; (b) studies should be 

 done both to verify the effectiveness of AHDs and to 

 assess the risks to target and non-target species; and 

 (c) some form of licensing or prior authorization 

 should be required for both operational and experi- 

 mental use of these devices until the risks have been 

 assessed and determined to be negligible. 



As noted in its previous report, the Commission 

 does not believe that the National Marine Fisheries 

 Service has appropriately considered the workshop's 

 conclusions regarding the use and possible adverse 

 effects of high-intensity AHDs. In particular, the 

 Commission believes that the Service has neither 

 undertaken nor required the aquaculture industry to 

 undertake studies to determine whether such devices 

 could cause serious injury to marine mammals or 



other marine species. Neither has it restricted the use 

 of such devices pending resolution of uncertainties. 



High-Energy Seismic Surveys 



The oil and gas industry uses towed arrays of 

 airguns and other devices to generate high-energy 

 sounds that penetrate the ocean floor to delineate 

 possible geological formations bearing oil and gas 

 resources. Such sounds can travel long distances and 

 have been found to affect the movements and behavior 

 of certain marine mammals, sometimes at distances of 

 10 km (6.2 miles) or more. 



Available information often is insufficient to 

 determine a priori how different marine mammals 

 may be affected by seismic profiling. As noted in the 

 Commission's previous report, the Pacific Office of 

 the Minerals Management Service held a workshop on 

 12-13 June 1997 to review available information and 

 identify research and monitoring needed to better 

 document the possible effects of high-energy seismic 

 surveys on marine mammals. The meeting partici- 

 pants included a panel of acoustic and marine mammal 

 experts. A final report of the workshop was expected 

 to be completed early in 1998. However, at the end 

 of 1998 it had not yet been completed. 



Related Minerals Management Service Actions 



In the past 20 years, the Minerals Manageme.it 

 Service has funded a broad range of studies to deter- 

 mine the possible effects of offshore oil and gas 

 exploration and development on marine mammals 

 (see, for example, Waring 1981-1998, Appendix B). 

 One such study was an assessment of the species, 

 numbers, and environmental factors affecting the 

 distribution of cetaceans in areas of the northern Gulf 

 of Mexico where they could be affected by offshore 

 oil- and gas-related activities. This program, known 

 as the GulfCet Program, was funded by the Service in 

 response to information needs identified by partici- 

 pants in a Service-sponsored workshop on sea turtles 

 and marine mammals in the Gulf of Mexico held in 

 August 1989. The fieldwork was completed in 1998 

 and the program report is expected to be submitted to 

 the Service in the first half of 1999. 



169 



