“Acoustic measurements in the Northeast Pacific indicate t

“Acoustic measurements in the Northeast Pacific indicate that underwater noise levels in the open ocean have been rising for at least the last five decades

due to increases in shipping (Andrew et al., 2002, McDonald et al., 2006 and Chapman and Price, 2011) correlated to global economic growth (Frisk, 2012). Closer to shore, escalations in human activity, including shipping, pile-driving and seismic surveys, have transformed coastal marine soundscapes (Richardson et al., 1995 and Hildebrand, 2009) with uncertain consequences for the ecosystems that inhabit them. These large-scale changes in the acoustic environment are of particular concern for marine mammals Casein Kinase inhibitor (Tyack, 2008), which rely on sound as their primary sensory mode. There is growing evidence that marine mammals perceive anthropogenic noise sources as a form of risk, which is then integrated into their ecological landscape, affecting their decision-making processes (Tyack, 2008). Noise also has the selleck compound potential to mask important acoustic cues in marine mammal habitats, such as echolocation and communication (Erbe, 2002 and Jensen et al., 2009), and may disrupt their prey (Popper et al., 2003) affecting foraging. These anthropogenic pressures may lead to physiological

stress (Wright et al., 2007 and Rolland et al., 2012), habitat degradation, and changes in behaviour (Nowacek et al., 2007) including evasive tactics (Williams et al., 2002 and Christiansen et al., 2010) and heightened vocalisation frequency (Parks et al., 2007), rate (Buckstaff, 2004), or duration (Foote et al., 2004). The cumulative cost of these responses can alter the animals’ activity budget (Lusseau, 2003) and energy balance, which may have downstream consequences for individual vital rates (e.g. survival or reproductive success) and, ultimately, population dynamics. Efforts are underway to develop a framework to predict such population consequences of acoustic disturbance (PCAD; National Research Council, 2005). Detailed investigation

of these chronic and cumulative effects will require longitudinal studies of ambient noise trends in marine habitats with concurrent assessment of marine ifenprodil mammal fitness and population levels. However, long-term ambient noise data (on the scale of several or more years) are limited to the Northeast Pacific (e.g. Andrew et al., 2002, McDonald et al., 2006 and Chapman and Price, 2011) and data for other ocean basins and coastal regions are rare and comparatively brief (e.g. Moore et al., 2012 and Širović et al., 2013). In the European Union (EU), a regulatory framework which seeks to rectify this knowledge deficit is currently developing guidelines for ambient noise monitoring (EU, 2008, Tasker et al., 2010, Van der Graaf et al., 2012 and Dekeling et al., 2013).

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