.2.5. Major Behavioural Disturbance Levels for Marine Harbour PorpoiseEven if underwater noise produced by human activities is known to produce effect to the following site the marine life, including fishes or birds, we propose an illustration to compare our data and model results with known level for the most common marine mammal present in Belgian water. For the harbour porpoise Phocoena phocoena, a major behavioural disturbance level, is found above Lp?p = 155dBre1��Pa [13]. 2.6. Regression Model for Noise PropagationA linear regression model based on the ordinary least square (OLS) was computed from the data presented at Table for??jacket,(4)in??for??monopileLz?p=?27.4log?(d)+259,5?dB??1:Lz?p=?27.4log?(d)+270.7?dB which d is the distance to the source. It has a transmission loss of 27.

4log (d) ranging within the 95% confidence interval from 30.5 to 24.3log (d). That model is further modified by the addition of an absorption term making use of absorption coefficient of 0.0004dB/m as proposed by [13] and the final model for??jacket.(5)3.????????????for??monopileLz?p=?27.4log?(d)+259,5?dB?0.0004d???????????readsLz?p=?27.4log?(d)+270.7?dB?0.0004d Results3.1. Underwater Noise Sound Pressure and Exposure LevelsThe highest normalised Lz?p of 194dB re 1��Pa was observed for the piling of the B10 monopile at the Blighbank, while for the piling of the jacket pinpiles a maximum of 189dB re 1��Pa was observed (CG3) at the Thorntonbank (Table 3). The lowest Lz?p value of 172dB re 1��Pa was observed for the piling of the jacket CB6, while the lowest Lz?p for monopiles was 179dB re 1��Pa.

The piling of the jacket foundation CG3 and the piling of the monopile A02 exert similar normalized Lz?p values of about 186dB re 1��Pa. Some lower normalized Lz?p (by 15 to 20dB re 1��Pa) is observed for the piling of the jacket CB6.Table 3Normalized @ 750m zero to peak sound Drug_discovery pressure level (Lz�Cp) in dB re 1��Pa. Normalized @ 750m mean and maximum sound exposure levels (SEL) in dB re 1��Pa2s. Normalized maximum SEL values range between 151 and 178dB re 1��Pa2s. The maximum observed normalised SEL for jacket foundation piling was 178dB re 1��Pa2s (CG3), while the maximum observed normalized SEL for monopiles (B10) was some 10dB lower with a maximum of 166dB re 1��Pa2s. Normalized mean SELs show similar behaviour with the highest value of 168dB re 1��Pa2s measured at CG3 and the lowest value for jacket piling of 145dB re 1��Pa2s (CB6). Normalized mean SELs for both steel monopile are in between with 168dB re 1��Pa2s for B10 and 164dB re 1��Pa2s for A02. Whereas statistically significant differences were detected between the four piling events for normalized maximum SEL (Kruskal-Wallis test: P = 0.016) and mean SEL (P = 0.