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

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Offshore wind power projects in the Great Lakes: Background and science considerations for fish and fish habitat To assess the potential for sediment-bound contaminants to be released upon dredging and subsequently taken up by fish or other biota, chemical analyses, sediment toxicity studies and bioassays should be performed on sediment cores collected throughout the project area prior to construction (U.S. Department of Energy 2009). Guidelines and protocols for these types of studies have been well-established and could be applied to sediment cores collected at prospective sites for wind power projects in the Great Lakes (e.g. Munns et al. 2002). If a project proceeds in an area where some contaminated sediments exist, a BACI-type experimental design that includes non-dredged reference sites might be most appropriate for testing the ecological impacts of dredging-related resuspension as it has been used with demonstrated success in the recent past (Knott et al. 2009). Sessile, filter-feeding invertebrates are generally thought to be good indicators for environmental contamination, and would be a good initial choice for monitoring potential contaminant uptake from dredged sediments in the Great Lakes. However, if these studies indicate that there is a concern for bioaccumulation, an additional option would be to monitor contaminant concentrations in local fish because their consumption could pose a health risk to humans. 5.7 Quantifying the effects of introduced hard substrate on local biota While turbine foundations and scour protecting materials could create novel habitat for certain Great Lakes fish and aquatic invertebrates, there is a pronounced lack of knowledge regarding the potential effects that these artificial hard substrates will have on both fishery resources and on the spread of invasive species, among other things. Targeted monitoring studies of local fish and benthic invertebrate communities associated with these structures will therefore be vital to addressing some of these knowledge gaps. Here again, comprehensive baseline assessments of the abundance, distribution and diversity of fish and invertebrates within the proposed project area are needed to serve as a basis for comparison with post-construction monitoring, and to ensure that any community changes resulting from the presence of wind turbines can be detected. However, as noted above, it can often take many years after an impact (in this case the introduction of novel substrate) to detect successional changes in invertebrate communities or changes in the abundance and diversity of local fish assemblages. For this reason, longer postconstruction monitoring would be warranted to assess the habitat creating potential of wind turbine foundations; this could very well serve to benefit proponents wanting to document and Aquatic Research and Development Section 66
Offshore wind power projects in the Great Lakes: Background and science considerations for fish and fish habitat showcase the positive aspects of turbine installations, and could help to inform future developments. Approaches to monitoring the development of fouling communities on submerged turbine structures are relatively straightforward owing to the fact that most epifaunal invertebrates are sessile or slow moving. A commonly employed method at marine wind power projects is to use underwater cameras to periodically capture either video or pictures of the foundation surfaces that can subsequently be analyzed to identify species composition and percent coverage (Kjaer et al. 2006). Alternatively, divers can visually observe and record the species present or collect representative samples to be analyzed in the lab for estimates of biomass, diversity or even individual growth rates (Wilhelmsson & Malm 2008). A gradient design approach to assess the extent of the impact that turbine foundations and scour protection could have on infaunal or epibenthic invertebrate communities might be the best option. This has been done to test the effects of newly installed offshore gas platforms on benthic communities which might be similar to those anticipated from the installation of offshore wind turbines. In one such recent study (Manoukian et al. 2010), sediment samples were taken at increasing distances from each platform, and the organisms within them identified and counted to obtain measures of species abundance, diversity and evenness—all good biological indicators of environmental impacts. Pre- and post-construction infaunal community surveys were conducted in a similar manner throughout the wind power project area at both Horns Rev and Nysted, although here investigators followed more of a BACI-type design (Kjaer et al. 2006). In these surveys species biomass was additionally determined, which is another useful biological metric for comparing between sites or before or after an impact. The effect of the introduction of artificial hard substrates on fish, which could include an artificial reef or fish attraction effect, will likely prove less straightforward to monitor than impacts on benthic invertebrate communities. Not only are fish mobile, utilizing different lake habitats through the year or even across a 24-hour cycle, but they also occupy three-dimensional space as opposed to the two-dimensional space occupied by fouling or benthic invertebrates, making them more difficult to monitor. In addition, the potential attraction effect that the introduced hard substrate and vertical relief associated with wind turbine foundations might have Aquatic Research and Development Section 67
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Offshore Wind Power Projects in the Great Lakes - Ministry of ...

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