Chapter VI — Effects of Pollution 



whether the Navy and others have routinely collected 

 information on the characteristics and levels of ambi- 

 ent noise; (2) whether the information is unclassified 

 and, if not, whether it might be made available in 

 some unclassified, synthesized form; (3) whether the 

 Navy believed it would be possible and useful to 

 analyze the information to document changes and 

 trends in ambient noise in representative ocean areas 

 and marine mammal habitats; and (4) whether the 

 Navy would be willing to undertake such a project. 



The Navy responded on 28 October 1998, noting 

 that, for many years, it has collected information on 



ambient noise in the world's oceans. It outlined the 

 available databases and noted that, because they rely 

 more on estimations and modeling than actual mea- 

 surements, they likely would be of limited use in 

 quantifying long-term changes in levels and frequen- 

 cies of ambient noise. The letter noted that efforts 

 were under way to improve the databases to support 

 operational requirements. It indicated that the Navy 

 would be happy to provide a detailed briefing on its 

 ambient noise databases to more fully assess their 

 potential usefulness for the purposes outlined in the 

 Commission's letter of 30 July 1998. The Commis- 

 sion plans to accept this offer early in 1999. 



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