ENVIRONMENTAL STATEMENT BARDOLINO DEVELOPMENT

Bardolino Development Environmental Statement
should not be seen as rigid, unchanging descriptions of presence or absence. Spawning
times represent the generally accepted maximum duration of spawning (Coull et al., 1998).
After spawning, fish hatch quickly from their eggs and many species remain in the water
column as larvae, consuming microscopic organisms and gradually developing the body
shape and behaviour patterns of adults. At this stage of the life cycle, many species occupy
discrete areas, either in the water column or on the seabed, where opportunities for feeding,
and for protection from predators are greatest. Juvenile fish can often be found in nursery
areas together with slightly older individuals, and occasionally adults. The prevailing water
temperature and availability of food can alter the position of these nursery grounds from year
to year. As a result of these factors it is difficult precisely to define the limits of nurseries. The
maps in Figure 4.8 therefore give an indication of the likely positions of juvenile
concentrations around the UK, rather than a definitive description of the limits of all nursery
grounds (Coull et al., 1998). Nursery grounds are used throughout the year, potentially
making it impossible for an operation to avoid being coincident with the presence of juvenile
fish. Seismic surveys and the placement of structures on the seabed (CEFAS, 2001b) may
have an impact upon fish spawning grounds, but as yet there is no direct evidence to suggest
that these activities cause significant disturbance to nursery areas.
Bardolino development activities are scheduled to occur between March and August 2009
(Section 3.3.2); these would coincide with the spawning periods of mackerel, Nephrops
(Norwegian lobster), lemon sole and Norway pout (Table 4.12). Species such as mackerel
lemon sole and Norway pout typically have pelagic eggs that are released into the water
column. The eggs and larvae of lemon sole remain planktonic after hatching, until they
mature and become demersal. Mackerel eggs and larva remain planktonic after maturation.
Nephrops benthic spawners, laying their eggs on the seabed and therefore may be at more
risk from smothering and activities that disturb the seabed.
Table 4.12 Spawning periods of fish which would coincide with the Bardolino
development [Months in yellow indicate the proposed development schedule]
Species J F M A M J J A S O N D Nursery
Mackerel
Nephrops * * *
Lemon sole
Norway pout
Haddock
Blue whiting
spawning period nursery/juveniles
* Peak spawning period
Source: Coull et al. (1998)
Mackerel are fast-swimming pelagic fish that are widespread in North Atlantic shelf waters.
The North Sea stock of mackerel has been at a very low level for many years due to high
fishing pressure and poor recruitment (DTI, 2001). North Sea mackerel over-winter in the
deep water to the east and north of the Shetland Islands, and on the edge of the Norwegian
Deeps. In spring, they migrate south to spawn in the North Sea between May and August
(CEFAS, 2001b).
Norway lobsters (Nephrops norvegicus) are mud-burrowing animals and are limited in their
distribution by the extent of suitable sediments, which are sandy mud to very soft mud. They
do not migrate, and spend their life in the area in which they settle as larvae. Mature females
carry eggs from September to April or May, although there is a tendency for Nephrops located
in northerly waters to spawn later in the year. After hatching, the larval stage lasts 6 to 8
weeks, before settlement to the seabed (CEFAS, 2001b).
Because they live in burrows and are therefore unable to move away, Nephrops are
vulnerable to smothering and the disruption of seabed sediments. Although Nephrops may
be vulnerable to smothering resulting from the drilling and pipeline activities associated with
the proposed development, these effects would be of relatively short duration and occur over
very localised areas of the seabed.
April 2008 Page 4-25