C. Receiver 



A critical element in the application of the source-path-receiver 

 model to estimate animal response to sound is the specification of the 

 particular species of animal which will be the receiver, and the conditions 

 under which the listening will be done (quiet background, or high ambient 

 noise due to high sea state, ship traffic, or activities of other noisy 

 animals). The outer continental shelves comprise habitats for almost all 

 species of marine mammals. This includes the large whales, both mysticete 

 (baleen) and odontocete (toothed), smaller odontocetes (dolphins and 

 porpoises), and pinnipeds (seals and sea lions). Their hearing capability 

 varies markedly from species to species, particularly with respect to the 

 frequency of maximum sensitivity. Much is known about the hearing of the 

 smaller odontocetes and pinnipeds (Herman and Tavolga, , 1980) as a result of 

 many experiments on captive animals. On the other hand, very little is known 

 about the hearing of the large whales, because of the great difficulty of 

 conducting controlled experiments on these animals. 



G-20 



