to the maximum range of instantaneous PTS in harbour porpoise ( up to 1km see Table 12.14).
275. Plate 9.4 in Appendix 9.1 suggests that starting ranges in pinnipeds are much greater than in cetaceans (approximately 16km). Therefore, there is the potential for exposure to noise levels that could cause PTS for harbour and grey seal.
276. It is not possible to quantify the number of individual seals of either species that could develop PTS following exposure due to the large amount of uncertainty in the use of this metric. However, given the extremely low densities of harbour and grey seal in the East Anglia THREE site the magnitude of effect is assessed as low in both species, and in relation to the south east England MU for harbour seal.
12.6.1.1.2.3 Auditory injury (TTS onset) 277. For pinnipeds and harbour porpoise, a fleeing response is assumed to occur at the same noise levels as TTS onset, and the potential impact described as ‘likely avoidance of area’ (see Appendix 9.1) is assessed in section 12.6.1.1.2.4 below.
278. For EPS other than harbour porpoise, the fleeing response is also described at TTS onset thresholds, and is predicted to occur at ranges of less than 500m in both low and mid frequency cetaceans for the maximum hammer energy (see Table 9.7 and Table 9.8 in Appendix 9.1). Therefore, as a result of the establishment of mitigation zones through the MMMP, no EPS should be exposed to noise levels that could lead to an injury offence.
12.6.1.1.2.4 Behavioural response 279. As outlined previously, the response of individuals to a noise stimulus will vary. However, for the purpose of this assessment, it is assumed that at the ‘likely avoidance’ range 100% of the individuals exposed to the noise stimulus will respond (flee response). At the ‘possible avoidance’ range, a smaller proportion of the individuals exposed to the noise stimulus are expected to show an avoidance response.
280. The numbers of individuals exposed to disturbance at these ranges, based on spatial and temporal worst cases are quantified below. The worst case overall magnitude of effect is considered in the assessment. Behavioural impacts and TTS are temporary, and will be limited to occurring in this phase of the development, although the duration of the temporary effect will vary.
Preliminary Environmental Information May 2014
East Anglia THREE Offshore Windfarm
Chapter 12 Marine Mammal Ecology Page 74
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