Underwater Noise Description Marine animals use sound underwater in the same way that humans and land animals use sight to communicate, navigate, interact, forage, and avoid predation. Marine animals are subject to many sources of anthropogenic noise in the ocean from shipping or other marine industries, to which the noise from marine energy devices is added. This noise can cause stress, behavioral changes (e.g., avoidance), physical injuries, temporary or permanent reductions in hearing ability, and can also mask other important sound cues in the marine environment. The effects vary by species based on noise detection and vocalization capabilities, which range across many frequencies and sound levels. Assessing the potential effects of underwater noise from MRE devices on marine animals requires that we understand the existing (or ambient) noise environment, measure the noise output from MRE devices and the distance it travels, and relate that sound to changes in animal behavior.
Level of knowledge/uncertainties The risk to species due to underwater noise from small numbers of MRE devices is considered to be low. Marine mammals and fish are the most likely marine animals to be affected, though there is also evidence that some sea turtles and invertebrates may also be affected. While sound detection and vocalization capabilities vary by species, any potential serious impacts on marine species can be avoided by managing and reducing the noise level of deployed devices. To date, measurements from single devices show that the level of MRE-generated underwater noise is considerably lower than levels expected to cause physical harm or affect the behavior of marine animals.
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Marine Renewable Energy: An Introduction to Environmental Effects
