Environmental Statement - Maersk Oil

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Balloch Field Development Environmental Statement
Section 3 Baseline Environment
cetaceans and the 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:
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 the 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 whales (sei, fin, pygmy sperm, Cuviers beaked, humpback and beaked) and dolphins
(short beaked common dolphin, striped dolphin and Risso’s dolphins). Killer whales and long finned
pilot whales have been sighted in higher numbers in the NNS, while large numbers of common
bottlenose dolphins are to be found along the coastal regions of the UK (Reid et al., 2003).
The CNS is home to relatively large numbers of minke whales, white‐beaked dolphins, Atlantic white‐
sided dolphins and harbour porpoises. A brief description of four key CNS cetacean species is
provided in Table 3‐13.
Table 3‐13 Overview of cetaceans found in high numbers in the offshore CNS area (Reid et al., 2003;
JNCC, 2008).
Species Description
White‐sided dolphin
Lagenorhynchus acutus
White‐beaked dolphin
Lagenorhynchus
albirostris
Minke whale
Balaenoptera
acutorostrata
Harbour porpoise
Phocoena phocoena
These dolphins show both seasonal and inter‐annual variability. Within the CNS they
have been sighted in large pods of 10‐100 individuals. They can be sighted in the
deep waters around the north of Scotland throughout the year and enter shallower
continental waters of the North Sea in search of food.
This species is usually found in water depths of 50 m to 100 m in pods of around 10
individuals, although larger pods of up to 500 animals have been sited. They are
present in UK waters throughout the year, although more sightings have been made
between June and October.
Minke whales usually occur in water depths of 200 m or less and occur throughout
the Northern and Central North Sea. They are usually sighted in pairs or in solitude,
although feeding groups of up to 15 individuals have been recorded. Minke whales
make seasonal migrations to the same feeding grounds.
Harbour porpoises are frequently found throughout UK waters. They usually occur
in groups of one to three individuals in shallow waters, although they have been
sighted in larger groups and in deep water. It is not thought that this species
migrates.
When estimating population sizes of cetacean species within the North Sea (SMRU, 2008), the region
was divided into several areas as shown in Figure 3‐16 (JNCC, 2008). The Balloch development is
located within area T but is reasonably close to area V. Estimated abundance and densities (animals
per km 2 ) of cetaceans within the development area based on shipboard surveys are provided in Table
3‐14. Harbour porpoise, minke whale, white‐sided and white‐beaked dolphins may occur in the
development area, albeit in low numbers (SMRU, 2008).