Alternative energy development posing unknown risks to marine life

The proliferation of offshore wind, wave, and tidal energy projects, constructed in response to global concerns about climate change and energy security, have been greeted with caution by marine conservationists, who question their possible detrimental consequences on sea life.

Numerous studies have been undertaken to study the behavioral and physiological effects of noise and electromagnetic fields produced by the alternative energy developments on fish, mammals, and benthic populations, and work is ongoing to develop appropriate solutions to mitigate potential impacts.

In France, a series of studies is underway as part of the three-year SPECIES project, which aims to improve knowledge about the potential interactions between benthic organisms in coastal marine ecosystems and direct electrical connection cables from marine renewable energy projects. The effects of island-continent submarine power connections are also being monitored.

“Impact studies are important to France Energies Marines, as the first commercial off-shore wind farms will soon be up and running here in France, and we need to ensure that they will be accepted,” Mélusine Gaillard, the scientific communication officer for France Energies Marines (FEM), told SeafoodSource. “The current studies will address the direct impacts due to changes in electromagnetic fields and temperature, and indirect impacts such as loss of habitat for commercial benthic species, including lobsters and spider crab.”

The European lobster is a valuable shellfish stock for French fishermen, with landings worth more than EUR 150 million (USD 170 million) per year, and the animals are known to frequent the electrical connection corridors of several marine renewable energy projects.

Bastien Taormina, a doctoral scholar studying the issue in conjunction with Ifremer and FEM, has been using laboratory experiments to look at the response to an electromagnetic field of three-week old lobsters, which measure just one centimeter in length. The lobsters are particularly vulnerable at this age, and no research had previously been carried out on juveniles so young, Taormina said.

“We wanted to determine if the juveniles were attracted or repelled by the electromagnetic field, or if they remained indifferent. We also studied the effects of a seven-day exposure to an electromagnetic field on mortality and the natural behavior of the animal, including its ability to find shelter,” Taormina said.

Analysis of video recordings is still being undertaken and the study results will be published at the end of 2019, Taormina said.

At sea, measurements are regularly carried out on the seabed over three underwater cables between the Cotentin Peninsula and the Island of Jersey. 

"Our goal is to gather in-situ data of the magnetic field emitted near operational cables, because this is valuable for validating models of theoretical calculations, at a time when marine renewable energy projects are multiplying,” Ifremer scientist Antoine Carlier told SeafoodSource. “The aim is firstly to assess whether the natural magnetic field is increased in the cable corridor, then to assess the impact on living organisms.”

A separate study carried out near a hydroelectric test site in Brittany, France, is monitoring a series of 100 concrete mattresses, which have been placed on the seabed to stabilize an electrical connection cable in the vicinity of a tidal turbine test site.

Regular dives are allowing scientists to count and video track the species that colonize the structures, and so far, they have found lobsters under each mattress within 10 centimeters of the cables. 

In the United Kingdom, marine scientists from Edinburgh’s Napier and Heriot-Watt Universities have just reported that underwater noise from ships can induce stress in mussels, affect their eating habits, and damage their DNA, with unknown consequences. 

The laboratory research, which measured biochemical and behavioral changes in mussels in response to a recording of a ship’s motor, led the scientists to the conclusion that noise pollution caused by shipping, oil and gas exploration, and renewable energy devices is of potential concern. 

However, the impact of noise does not appear to be fatal or immediately dangerous for mussels, although it could be affecting their growth and ability to reproduce, and may help to explain the decline of natural mussel beds in some areas of the U.K., according Napier scientist Karen Diele.

“The blue mussel is an extremely important invertebrate in the U.K.; It is commercially valuable and also plays an essential ecological role as a reef builder and a filter-feeder that keeps the water clean,” Diele said. “It's important that we understand how noise is stressing mussels in environmental risk assessments so that we can ensure environmental policy and regulation is effective."

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