Greening Blue Energy - BioTools For Business

Above water, WTC devices have very few moving
parts, and have relatively low profiles, which should
decrease the risk of fatal bird collisions (see section
2.2.1. in Annexe 1). Obstruction lights (Montevecchi
2006, and see Cruz 2008 for references), as well
as congregations of fish (see below), may, however,
attract seabirds and thereby increase the risk of
injuries due to collision for these devices. Impacts
of WTC parks on the behaviour and migration of
seabirds cannot be ruled out (See Annexe 1. Sections
2.2.2. and 2.2.3.). Further, the physical footprint
of OWC devices (Figure 2) placed in the littoral
zone could in some cases cause direct habitat loss
for birds residing on the shores.
As for offshore wind power (see Annexe 1, sections
1.1., 1.4., and 2.1.1.), the construction of WTC
devices will increase the amount of hard substrate
in coastal environments and may thus positively
affect abundance of several taxa (Langhamer &
Wilhelmsson 2009, Figure 6). Results from studies
on foundations of wave energy converters confirmed
that the structures are rapidly colonised
by epifauna, fish, and crusteaceans, with increas-
Figure 6: An edible/brown crab (Cancer pagurus) taking shelter on a wave energy foundation.
Photo: O. Langhamer.
74 GREENING BLUE ENERGY - Identifying and managing biodiversity risks and opportunities of offshore renewable energy
ing diversity over time (Langhamer & Wilhelmsson
2007, Langhamer & Wilhelmsson 2009, Langhamer
et al., 2009b). One current case study is the wave
power park that has been under development on
the Swedish west coast since 2005 (Langhamer &
Wilhelmsson 2007, Leijon et al. 2008). Within the
environmental research package associated with
the project, there is potential for low cost modifications
to the design of the foundations in order to
encourage the colonisation of fish and shellfish that
are of particular interest. The current research primarily
targets species that are habitat limited, and
seeks to augment local stocks where desired (e.g.
Langhamer & Wilhelmsson 2009, Figure 7). On the
other hand, the study has shown that increased
abundance of predators (i.e edible i.e. Cancer pagurus)
may have adverse effects on local numbers of
certain species. Further, WTC parks will provide
hard substrata in regions and at depths often dominated
by soft bottom habitats, and could fill in gaps
between natural areas of hard substrata, changing
the biogeographic distribution of rocky bottom species
within a region (Bulleri & Airoldi 2005, Nielsen
et al 2009). See Annexe 1, sections 1.1., 1.4., and
2.1.1., for more issues related to the addition of
artificial hard substrata.
WTC devices on the water surface (i.e. for wave
power) may act as fish aggregation devices (FAD)
and attract both juvenile and adult fish (Kingsford,
1993, Castro et al. 2002, Fayram & de Risi 2007).
Still, the functions and area of influence from different
types of FADs remain unclear and require further
investigation (Dempster & Taquet, 2004).