Environmental statement - Flyndre and Cawdor - Maersk Oil

Species
5‐ 22
Flyndre and Cawdor Environmental Statement
Section 5 Assessment of Potential Impacts and Control Measures
Density (individuals per km 2 ) and
abundance estimates (Area ‘V’‐ Central
North Sea)*
Number of animals exposed to
sound from piling (total area where
sound is above background levels X
density of animals)
Harbour porpoise
0.294
(47,131 harbour porpoises in area ‘V’)
577
Minke whale
0.028
(4,449 minke whales in area ‘V’)
54
Bottlenose
0.08
Not likely to be exposed coastal
dolphin
(123 bottlenosed dolphins in area ‘V’)
distribution
Lag. species
0.04
(6,460 Lag. Species in Area ‘V’)
78
*See Figure 3‐10 for location of Area ‘V’.
**Lagerorhynchus species are combined due to the difficulty in identifying similar species.
It is worth noting that the numbers provided are approximations e.g. they assume animals will be
distributed evenly throughout Area ‘V’. Therefore they should be considered a rough estimate of the
number of animals potentially exposed (calculations not applicable for bottlenose dolphins – coastal
distribution).
Table 5‐13 Abundance and density of marine mammals in the development area and approximate
numbers of individuals potentially exposed to piling sounds above the ambient noise level (Table
adapted from SCANS‐II, 2008).
A disturbance offence, as described by the Habitat Regulations, has been interpreted by JNCC as a
type of reaction that can cause a sustained or chronic disruption of behaviour scoring 5 or more in the
Southall et al. (2007) behavioural response severity scale. It is possible that relatively high numbers of
animals, for example 5,777 harbour porpoises, could be exposed to piling sound levels above their
hearing thresholds and be audible to them. Beyond the immediate zone of piling operations, the
levels of noise received are not likely to cause sustained or chronic disruption to behaviour. Beyond
the immediate piling area the received sound levels are more likely to induce minor behavioural
responses, for example, it is possible animals could move away to areas of lower sound levels. As the
duration of each piling event spans a relatively short time frame