As with the development of iPCoD, we collaborated with a team of researchers at the University of St Andrews, led by Prof. John Harwood – to explore how US Navy sonar might impact some of the marine mammal populations inhabiting ranges and whether PCoD frameworks could be used in assessments.
The potential risk of injury and/or disturbance to marine mammals during US Navy activities is assessed as part of standard environmental impact assessment processes. Possible consequences of exposure to underwater noise from US Navy sonar include; disturbance that could cause marine mammals to either move away or change behaviour, suffer temporary hearing damage or permanent physical injury. The interim PCOD model assesses what the longer term and larger scale impacts of these consequences are to the exposed group(s) of animals as a whole.
Such versions of the PCOD model are considered ‘interim’, because it was developed to help manage uncertainty within the current knowledge of marine mammals, where there are limited data available on some of the key information needed. For instance, relatively little is known about how changes in behaviour and hearing sensitivity caused by exposure to underwater noise affect the ability of individual marine mammals to survive and to reproduce (their ‘vital rates’). To combat this issue, SMRU Consulting received input from over 30 international marine mammal experts who delivered a range of opinions of how disturbance might impact on these vital rates of Blainville’s beaked whales and sperm whales.
You can read the main PCoD Lite report here, which details the overall approach, how we dealt with eliciting information from experts and how the outputs of PCoD might be tailored to the US regulatory system. We also produced a report applying the PCoD Lite model for the two species of interest on ranges in the Bahamas and Hawai’i. These are very much theoretical and speculative and we specifically note:
It should be recognised that the results presented in this report are not intended in any way as an assessment of the potential effects of Navy training and testing activities on beaked whale or sperm whale populations. Nor is it intended to influence regulatory policy or control over these activities. Rather, we have attempted to show how the Interim PCoD approach can be used with information that is routinely collected on some Navy ranges, such as AUTEC, or that is provided by the Navy Acoustics Effects Model to forecast these potential effects.