Renewable energies are an interesting alternative to the means of electricity production involving fossil fuels or hazardous materials. In addition to helping limit global warming, they only require abundant and inexhaustible sources of energy that can be found almost anywhere on the planet, such as the sun or the wind. What better way to reduce our impact on the climate and biodiversity?
Unfortunately, collisions of migratory birds and even bats with wind turbines are frequent and attract a lot of attention and concern. Nobody expects a flying whale suffer the same fate, but are offshore renewables nevertheless safe for marine life? In addition to onshore and offshore wind turbines, tidal power and wave power can be harnessed through a whole host of installations that pose various risks to cetaceans.
Underwater turbines obviously represent risks of collisions with marine mammals, although they don’t rotate as fast as ship propellers. They are also a potential source of constant noise that can interfere with communication and cause long-term stress. Ropes used to moor floating energy installations are much larger and tighter than those used for fishing equipment, but a risk of entanglement remains. Another consideration is the potential impact of the electromagnetic field surrounding the submerged high-voltage cables that connect the different units in an offshore energy park. It is difficult to assess whether this phenomenon may affect echolocation or interfere with species that use terrestrial electromagnetic fields to orient themselves.
If several marine energy farms are deployed in an area and each extends for several kilometers, they could represent a significant barrier to the use of critical habitat. Whales would then have to adapt their behavior, either by forgoing important food sources or by making long detours that could lead to fatal strandings. In addition, the construction of any type of offshore infrastructure involves a marked increase in noise and ship traffic, which can lead to permanent damage to the auditory system and an increased risk of ship strikes. At the end of their useful life, even the deactivation of wind turbines is a noisy undertaking: in other words, offshore energy farms can disturb marine mammals at every stage of their operation.
Finally, the installation of turbines and platforms exploiting ocean currents causes changes in water and sediment flow, which can unleash a cascade of unexpected and startling effects at all levels of the ecosystem. The domino effect can extend across distant, yet intimately connected habitats: consider the impact of hydroelectric dams harnessing rivers in British Columbia on the spawning cycle of salmon, causing significant food loss for resident Pacific killer whales and driving them to extinction.
Fortunately, mitigation of biodiversity impacts is now being considered in the development of marine energy technologies. During construction, soundproof bubble curtains are deployed and various noise reduction systems make drilling and piling less disruptive to nearby animals. Similarly, permanent installations such as turbines and moving leaves are designed to minimize the noise stress caused by their operation.
But the best solution to avoid disturbing marine mammal populations is to avoid siting marine energy farms across migration routes and in critical feeding and breeding areas. To implement these solutions, data on the presence of animals, whether by direct observation, or aerial, satellite, and infrared photography, is needed to establish with certainty the distribution and migration patterns of populations, and to make informed choices about the location of future facilities. In addition, real-time marine mammal detection systems could contribute to a mode of operation where the most noisy and dangerous activities are interrupted when vulnerable animals are present. By developing technologies that allow for the rapid detection of whales in photos of various provenances, Whale Seeker is working to ensure that solutions to the climate crisis are deployed in a way that preserves ecosystems and biodiversity.