Effects of EMFs from Undersea Power Cables on Elasmobranchs and Other Marine Species.

Anthropogenic electromagnetic fields (EMFs) have been introduced into the marine environmentaround the world and from a wide variety of sources for well over a century. Despite this, littleis known about potential ecological impacts from EMFs. For decades, power transmissioncables have been installed across bays and river mouths, and connecting near-shore islands to themainland, with little consideration of possible effects to marine species from EMFs. At a time ofgreater environmental awareness, the US now faces the possibility of a new source of EMFs overa much greater extent of the seabed from offshore renewable energy facilities in coastal waters.This literature review synthesizes information on the types of power cables and models theexpected EMFs from representative cables. Available information on electro- and magnetosensitivityof marine organisms, including elasmobranchs (sharks and rays) and other fishspecies, marine mammals, sea turtles, and invertebrates is summarized and used in conjunctionwith the power cable modeling results to evaluate the level of confidence the existing state ofknowledge provides for impact assessment. Gaps in our knowledge of power cablecharacteristics and the biology needed to understand and predict impacts are summarized andform the basis of recommendations for future research priorities. Potential mitigationopportunities are described with a discussion of their potential secondary impacts as well assuggested methods for monitoring mitigation effectiveness. Finally, because interest in offshorerenewable energy has increased throughout US coastal waters, there is a concern that organismscould be exposed to multiple seabed power cables. Cumulative effects of this exposure are discussed.