PCAD

Synopsis

There is growing public and scientific concerns that exposure to acoustic disturbance affects behavior and health of marine mammals. Although observed changes may not appear to be directly harmful in themselves, they could result in changes in energy budgets, mortality risk, and reproduction. Because the sound threshold at which such responses have been observed in some species is relatively low, large numbers of marine mammals could be affected by a single sound source. Other species are sensitive to low frequency sound, which carries long distances through the water.

The final report of the US National Research Council’s Committee on Characterizing Biologically Significant Marine Mammal Behavior (NRC, 2005) concluded that “…we are a decade or more away from having the data and understanding of the transfer functions needed to turn such a conceptual model into a functional, implementable tool.” However, since that time there have been substantial advances in knowledge of how marine mammals respond to acoustic disturbance and emerging modeling tools that could help to quantify how responses might affect energy budgets and survival.

ONR has established a Working Group that is developing models of the population consequences of acoustic disturbance for a number of marine mammal species and populations. Hierarchical models are being developed to quantify how environmental variables affect the behavior and health of individuals and growth of populations.