Recent reviews of mitigation measures to minimize impacts of high intensity sound sources, for both seismic surveys Angiogenesis inhibitor conducted during oil and gas development (Weir and Dolman, 2007 and Parsons et al., 2009) and military activities (Dolman et al., 2009a), have been critical of the standard

methods (which tend to rely on visual observers) as being inadequate, concluding that they cannot prevent cetaceans from being affected by sound. There have also been numerous court cases in the US related to the impacts of military sonar on cetaceans, with most relating to concerns about the effectiveness, or lack thereof, of mitigation measures being used by the US Navy (Zirbel et al., 2011a). Moreover, preliminary surveys of the general public just outside Washington DC in the US suggest that the overwhelming majority of people www.selleckchem.com/products/PLX-4032.html believe that sonar has a negative impact on cetaceans (Zirbel et al., 2011b) with many also of the opinion that naval activities should be moderated to reduce impacts. The European Cetacean Society (ECS) has been heavily involved in the underwater noise issue, in particular the impacts of active sonar. A workshop on active sonar and cetaceans was held at the ECS annual conference in 2003 (Evans and Miller, 2004) that helped to document the association between atypical mass strandings of beaked whales and naval

sonar exercises. A further ECS workshop focusing on beaked whale research (Dolman et al., 2007) gathered scientific knowledge on beaked whales and in mitigation techniques, including acoustic and visual detection, distribution mapping and modelling. Concerns over a lack of implementation of protective measures for cetaceans in Europe (for example, see critique in Parsons et al., 2008) and the abovementioned inefficacy of mitigation measures led to a third workshop being held on beaked whales at the 2009 ECS Annual Conference. Presentations from this workshop are contained within this special issue.

Ongoing research is largely focused on the aminophylline responses of individual beaked whales to naval active sonar, while a clear protocol on how to use these results to design mitigation guidelines is currently lacking. Therefore an urgent requirement remains to design an effective monitoring and mitigation protocol that can minimize the risks of intense sound sources harming beaked whales and other species. The ECS workshop was designed to review recent advances in scientific knowledge around the issue and attempt to outline a way forward. Accordingly, the workshop was split into three sessions. The first session aimed to provide a background to the current field research investigating mitigation techniques, the needs and challenges, the behavioral responses of beaked whales to sound, and current mitigation measures for mid-frequency active sonar exercises.