case in terms of the resulting underwater noise and other foundation types are therefore not considered in this aspect of the assessment.
94. Using the modelled noise levels presented in Section 9.4 and the impact criteria for marine mammals and fish outlined in Section 9.5, it is possible to establish ranges or zones over which marine mammals and fish might be impacted during the construction phase of East Anglia THREE. This is based on the effects of marine impact piling, the most prevalent noise source associated with the construction of a windfarm.
95. As discussed in Section 9.4, a range of hammer blow energies were considered to represent the range of sound levels that may be experienced at East Anglia THREE.
96. Noise would also result from vessels used during the construction of the windfarm. However, noise levels reported by Malme et al. (1989) and Richardson et al. (1995) for large surface vessels indicate that physiological damage to marine fauna is unlikely, although the levels could be sufficient to cause local disturbance of sensitive marine fauna in the immediate vicinity of the vessel, depending on ambient noise levels.
9.6.1.1 Marine Mammals
9.6.1.1.1 Onset of Auditory Injury (PTS Onset) 97.
The marine mammal injury criteria adopted for this assessment are outlined in detail in Section 9.5 and briefly summarised below. It should be remembered that these injury criteria are based on the PTS onset levels, representing an onset of auditory injury, not a complete hearing loss. It should also be noted that TTS has previously been shown to be limited to the hearing critical bands, in and around, the frequency of the fatiguing sound (e.g. Kastelein et al. 2012; 2013a). As a precursor to PTS, such limited frequency extent of TTS is likely to limit PTS to limited critical bands rather than the entire hearing range of the receptor.
98.
The injury impact ranges predicted for mid-frequency and low-frequency cetaceans are based on the PTS levels proposed by the NMFS Marine Mammal Injury Criteria Group (Southall et al. 2007), which are based on data from a beluga or white whale Delphinapterus leucas (Finneran et al. 2002a). As acknowledged by Southall et al. (2007), these may not be applicable to harbour porpoise for which no data existed at the time when these criteria were published. The publication by Lucke et al. (2009), which represents the earliest description of any high frequency cetacean being exposed to pulsed sounds, substantiates this assumption. Following this work, harbour porpoise injury ranges can be derived based on a TTS to PTS extrapolation of
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm Appendix 9.1 Underwater Noise Modelling 35
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