Impacts of noise pollution and disturbance by shipping
anthropogenic sounds that can cause hearing damage or affect fish and animal behaviour and communication in the ocean (MacCauley et al., 2003; Wellgart, 2007; Papanicolopulu, 2011; Zirbel et al., 2011). There is particularly increasing evidence on behavioural changes in cetaceans – whale and dolphins – when exposed to noise pollution (Nowacek et al., 2007; Lusseau, 2008).
Odontocete cetaceans (toothed whales) use high frequency echo-location sounds for navigating and foraging and are highly sensitive to artificial sounds in the ocean, and have par- ticularly the ability to detect and hear both very low and very high frequencies, dependent upon species. Mass strandings from a few to several hundred have occurred in numerous ce- tacean species, including beaked whales following military ex- ercises with sonar (Balcomb and Claridge, 2001), and of other whales, dolphins and porpoises. The causes of mass strand- ings are in all likelihood very diverse (Walker et al., 2005). Some may have been related to hearing loss possibly caused by boat noise, pollution (from PCB) or other causes, while others from a range of other factors including natural ones (Mann et al., 2010).
There are numerous studies on the impacts of dams and other infrastructure on hindering movements of salmonids, fish and river dolphins (UNEP, 2001; WCD, 2000 ).
However, there has in recent years been far more focus on the effect of noise pollution from shipping and recreational boats on marine mammals, including both naval military sonar and other
However, noise pollution from shipping may also have effects other than mass strandings, namely through causing cetaceans to avoid shipping lanes and harbours in previously important habitat and migration routes. Artificial sound has even been used effectively to deter killer whales from salmon farms (Mor- ton and Symonds, 2002). Avoidance of cetaceans to even few small-vessel tourist boats has been documented as a long-term effect, with possible implications for local populations (Bejder et al., 2006). More recent studies confirm substantial changes in cetaceans’ behaviour when exposed to boat noise, greater than previously suspected (Williams and Ashe, 2007; Bearzi et al., 2011; Seuront and Cribb, 2011).
Humpback whales (Megaptera novaeangliae) have been shown to alter behaviour near vessels (Stamation et al., 2010), and several studies show dolphins avoiding areas with boat traffic (Bejder et al., 2006). There are numerous studies documenting changes and