This page contains a Flash digital edition of a book.
o SEL injury criteria: 198dB re 1 μPa2·s (M-weighted) •


Injury criteria for pinnipeds in water: o SPL injury criteria: 218dB re 1 μPa (peak) (flat, un-weighted) o SEL injury criteria: 186dB re 1 μPa2·s (M-weighted)


62.


These limits are applicable for either single or multiple exposures within a 24 hour period. These criteria for injury are based on the US Marine Mammal Criteria Group method where the SPL limit is based on an addition of 6dB to the peak pressure known or assumed to elicit TTS-onset. The SEL limit is based on an addition of 15dB to the SEL know or assumed to elicit TTS-onset for any marine mammal exposed to single or multiple pulses.


63. More recent work by Lucke et al. (2009) suggested more precautionary injury criteria might be required specifically for harbour porpoise than that suggested by Southall et al. (2007) for a high-frequency cetacean. Lucke et al. (2009) measured TTS induced by a seismic airgun pulse with a peak pressure level of 194dB re 1 μPa (stated as 200dBpk-pk in Lucke et al. (2009)) and an SEL of 164dB re 1 μPa2·s. The approach adopted by Southall et al. (2007) of assuming PTS-onset (the basis for the injury criteria) results at an SPL 6dB above the level eliciting TTS-onset could also be adopted for harbour porpoise providing a peak pressure level injury criteria threshold of 200dB re 1 μPa. The same approach can be applied to SEL, where Southall et al. (2007) suggest an SEL 15dB above the level eliciting TTS-onset which provides an SEL injury criteria threshold of 179dB re 1 μPa2·s.


9.5.3.2 Behaviour (Marine Mammals) 64.


The behavioural response of marine mammals is perhaps somewhat easier to study than the relative health of their auditory system and several studies have been undertaken. There are, however, several species of interest and numerous potential sound sources and in addition to this, quantifying the mammal’s behavioural response is not easy. The US Marine Mammal Criteria Group recognises this and so in addition to compiling a database of relevant studies, they have created a severity scaling system applicable to multiple pulse sounds such as impact piling. For single pulses, however, they propose specific threshold levels in a similar fashion to auditory injury criteria described above. Both approaches are described below.


9.5.3.2.1 Multiple pulses (general piling activity) Behavioural disturbance criteria for multiple pulses are based on a severity scaling system, which ranks the behavioural response from a zero for ‘no response’ to a 9 for ‘outright panic, flight, stampede, attack of conspecifics or stranding events’


Preliminary Environmental Information May 2014


East Anglia THREE Offshore Windfarm Appendix 9.1 Underwater Noise Modelling 22


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150