Environmental statement - Flyndre and Cawdor - Maersk Oil

Flyndre and Cawdor Environmental Statement
Section 3 Environmental Baseline
Common seals were shown to predominantly spend their time at or near haul out sites, with short
trips to localised offshore areas. They were found occasionally to travel up to 45 km on feeding trips
of up to 6 days, although the duration of most trips was less than 12 hours (Thompson et al., 1990).
Grey seals on average spend the majority of their time within a similar range, with trip duration of less
than 3 days, although they occasionally make long‐distance trips of over 100 km (McConnell et al.,
1999). Trips by pups have been reported over large areas, for example from the Isle of May up the
Norwegian coast and down to the Netherlands (JNCC, 2007). However, the general pattern of close
proximity to haul out sites suggests that these distant trips are uncommon and are possibly made by
few individuals (Hammond, 2000). Since the area of the development lies approximately 270 km east
of the UK coastline neither grey seals nor common seals are likely to occur in the area.
CETACEANS
Many of the activities associated with the oil and gas offshore industry have the potential to impact
on cetaceans. The factors which could cause disturbance include noise or obstruction; however the
impact will depend on the scale and type of activity. Activities with the potential to cause disturbance
include; drilling, seismic surveys, vessel movements, construction work and decommissioning (JNCC,
2010 draft).
As marine mammals feed on fish and/or plankton, contamination of the water column affecting this
food source could have a negative impact on cetaceans, either directly as a result of lack of prey or
indirectly as a result of bioaccumulation of contaminants. However, as cetaceans tend to have large
feeding grounds, the localised contamination associated with the normal activity of gas and
petroleum installations is unlikely to have a major impact on individuals.
As with most species, an optimal survey design for monitoring population sizes of cetaceans would
involve surveying the species across its entire distribution at any one time. The impracticality of such
a task combined with difficulties of species identification have made it difficult to confidently assess
cetacean population sizes. The JNCC has complied an Atlas of Cetacean distribution in north‐west
European waters (Reid et al., 2003) which gives an indication of the types of cetaceans and times of
the year that they are likely to frequent areas of the North Sea. The Atlas is based on a variety of data
sources including;
at sea surveys carried out by the JNCC
the UK Mammal Society Cetacean Group
dedicated survey data collected in June and July 1994 by the Sea Mammal Research Unit at
St Andrews University (SCANS ‐ Small Cetacean Abundance in the North Sea).
Sightings of several species of cetacean have been recorded on the European continental shelf.
However in many instances within the North Sea recorded sightings are associated with single
individuals (Reid et al., 2003). Cetacean species sighted just once or in very low numbers in the North
Sea include both whales (sei, fin, and pygmy sperm, humpbacked and beaked whales (northern
bottlenose whale)) and dolphins (e.g. short beaked common dolphin, striped dolphin and Rissos
dolphins). Killer whales and long finned pilot whales have been sighted in relatively higher numbers
in the NNS while large numbers of bottlenose dolphins are to be found along the coastal regions of
the UK (Reid et al., 2003).
The CNS area is home to relatively large numbers of minke whales, white beaked dolphins, Atlantic
white sided dolphins and harbour porpoises. A brief description of these four species is given in Table
3‐13 while charts showing rate of sightings are given in Figure 3‐14.
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