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ODFW’s recommendations for a particular marine renewable energy (MRE) project depend on the location, device type, extent and duration of development. As such, each set of recommendations will be developed based on project-specific review. However, common amongst multiple proposed developments are some key concerns including but not limited to:
- Acoustics: Underwater sound is used by many marine organisms for navigation, orientation, prey location, predator avoidance, and other essential functions. Sounds produced by MRE in excess of ambient conditions may affect marine mammals that are federally protected by the Endangered Species Act or Marine Mammal Protection Act, and also state protected (e.g. gray whales remain listed under Oregon Endangered Species Act ORS 496.171, harbor porpoise and pinniped species are very nearshore species and are considered state resources). Acoustics could also affect fish species of concern (e.g. eliciting startle response in schooling fish, high level noise can cause damage to fish hearing).
- Seafloor habitat: Oregon state policy has established a management strategy and specific protections for shoreline and offshore rocky habitat through the Territorial Sea Plan. ODFW strongly recommends avoidance of rocky habitat for siting of MRE, due to the high diversity of marine organisms present at rocky reef habitat. Project structures on the seafloor (e.g. anchors, cables) will likely represent habitat conversion from soft-bottom to hard substrate, as well as indirect or induced habitat changes (e.g. scour) and short-term impacts (e.g. trenching for cable construction).
- Cable concerns: ODFW recommends avoidance of rocky reef habitat for siting of transmission cables which we recommend be buried in sand and mud. This is for many reasons having to do with biological and human use concerns (e.g. wanting to minimize the conflict between energy installations and bottom fishing). For the portion of the cable that crosses state waters, the Territorial Sea Plan also requires burial. Cable landing sites, where the electrical cable comes onshore to connect with the transmission grid, must be carefully considered to avoid or minimize impacts on sensitive habitats or other environmental resources.
- Electromagnetic fields (EMF): Several marine species use EMF for navigation and orientation, and fields produced by MRE may affect marine species’ essential life functions like orientation, navigation, or detection of prey but are not well understood in terms of what intensity or field strength would produce an abnormal or negative affect. EMF is naturally occurring and site-specific, meaning that the ambient field strength and propagation can vary by depth, sediment type, water movement, and other aspects of a site.
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| Dungeness crab forage on the APEX wave energy device under test off of Warrenton, OR, 2014. Photo credit and permission for use: M3 Wave, LLC. |
Fish attraction and community change: Over time, project equipment sited in soft-bottom open-water habitat will be colonized by algae and invertebrates, which will attract a new community of fish associated with the hard-substrate habitat that has been created at the site. Available data indicate that a new community will likely form around the facility soon after it converts open water soft bottom habitats into structured habitats with greater complexity, but what that community will be composed of and how long it will take to form remains unknown. This new community could have positive or negative effects on marine and avian species. Studying community change could help diagnose which project components introduce more or less risk to species, and could inform which species are most susceptible to risk presented by a given project. ODFW is interested in understanding what sort of change to expect at different depth zones in order to approximate when and where that might scale up to some sort of cumulative affect or trophic interaction with species of concern or fish stocks vital to fisheries.
- Onshore habitat: Grid-connected MRE projects will include energy transmission from the project site in the ocean to the onshore electrical grid, and may require ancillary onshore facilities. ODFW can help developers identify a shore crossing location, cable landing site, onshore cable route, and onshore facility site with minimal impacts (e.g. one that avoids sensitive wetlands, nest trees, mammal haulouts, salmon streams, and special status species). Where available, spatial data for terrestrial resources can be used in concert with input from ODFW biologists to delineate areas to avoid.
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