Offshore Wind Power Projects in the Great Lakes - Ministry of ...

Offshore wind power projects in the Great Lakes: Background information and science considerations for fish and fish habitat
Appendix C. Summary of the advantages and limitations of different fish sampling techniques that could be employed for baseline and
effects monitoring at offshore wind power projects. Methods listed first include those most commonly employed both for monitoring studies
at existing offshore wind power projects as well as for fish community surveys within the Great Lakes, followed by several additional
sampling methods that could be used.
Fish survey type Examples of where employed Advantages Limitations
Visual surveys
• Underwater cameras
• SCUBA diver surveys,
visual transects
Bottom trawl surveys
(beam or otter trawls)
• To monitor invertebrate
colonization/community
succession on submerged
turbine structures; to assess fish
use of artificial structures in the
Great Lakes
• To monitor epibenthic and
epibiotic invertebrate
assemblages on or around
submerged turbine structures; to
document fish use of artificial
reef structures in the Great
Lakes
• To survey and monitor fish
communities within offshore
wind power project areas (North
and Baltic sea) and at reference
sites; to conduct annual forage
fish monitoring in the Great
Lakes (USGS); employed by
Lake Ontario Management Unit
for stock assessments (OMNR)
• Photos or video can be analyzed to
identify species abundance/diversity
without requiring prolonged in-water time
for divers; cameras can document local
fish presence continually (i.e. in the winter
or when weather conditions render netting
or diving too risky); non-obstructive
method will not harm or scare fish away
• Spatial coverage enhanced by conducting
visual surveys along transects as opposed
to stationary cameras; aquatic species can
be counted and identified; behaviour and
habitat associations of fish can be
observed; non-destructive survey method
• Fish can be identified, counted and
measured; good catchability and
standardized abundance and biomass data
for certain species including a number of
commercially important species;
standardized approach allows for
comparison with historical stock
assessments; low mortality to fish
• Spatial coverage limited to area
within viewing range of camera; not
useful at night, under turbid
conditions or at depths where
light/visibility is limited (unless
equipped with light source)
• Diver access to sites can be
restricted under hostile weather
conditions; spatial coverage limited
to area within viewing range of
diver; ineffective at night, under
turbid conditions or at depths where
light/visibility is limited; some fish
species may be scared away by
presence of diver
• Low catchability for many pelagic
species (not representative of entire
fish assemblage in an area);
disturbance to lakebed possible;
applicability limited under certain
lake-bed conditions; sampling near
turbine foundations or cables risks
gear entanglement; limited to icefree
seasons
Aquatic Research and Development Section 110