In the marine environment there are natural magnetic and electric fields associated with both physical and biological sources, and there are anthropogenic electromagnetic fields (EMFs) that permeate it. Many marine animals can detect electric and magnetic fields and utilize them in such important life processes as movement, orientation and foraging. Here, these EMFs are explored and discussed in terms of how they arise, their properties (particularly those that are measurable) and the animals that have the ability to detect them. Then the evidence base for whether anthropogenic EMFs can affect sensitive receptor animals is explored. As marine renewable energy developments (MREDs) expand rapidly worldwide, with multiple devices and networks of subsea cables that emit EMFs into the marine environment, it is necessary to focus on their interaction with marine animals. The MRED industry has to take EMFs into account, so the industry perspective is also covered. Finally, suggestions are made on how research on EMFs associated with MREDs (and other sources) and its interaction with marine animals should advance in future.
Overview and TerminologyHumans are generally unaware that they live within an electromagnetic world. The concept that we are surrounded by charged particles may seem ethereal but is more real than generally acknowledged. We are familiar with an occasional lightning storm, but we are also bombarded continually with electromagnetic emissions from the sun and encompassed by the Earth's own geomagnetic field (and other sources, such as granite geology). At a local level, humans are immersed among anthropogenic electromagnetic emissions that emanate from the plethora of electrical appliances and technologies that have been developed to become part of everyday life.Animals with which humankind shares the environment are also exposed to electromagnetic fields (EMFs) both natural and anthropogenic in origin. Several animals are known to be able to detect EMFs (or more specifically the component electric and/or magnetic field) and to use them for activities that are vitally important in terms of resource gain and movement around their environment. This is particularly true of marine animals, many of which undertake large-scale movements that apparently follow the orientation of the Earth's geomagnetic field (Kirschvink 1997). Moreover, some animals possess specialist electroreceptive organs that can detect weak bioelectric fields emitted by their prey and conspecifics.Although knowledge of how marine animals use magnetic and electric fields is increasing, there is still scant understanding of how animals interact with anthropogenic sources of EMF. The purpose here, therefore, is to provide an overview of what is currently known about EMFs in the marine environment and to evaluate how electromagnetically sensitive receptor animals interact with the EMFs associated with marine renewable energy developments (MREDs). The latter are being developed to transform renewable sources of energy into electricity ...
