Report explores the potential entanglement risk for marine animals

The report finds that marine renewable energy (MRE) moorings are likely to pose a relatively modest risk of entanglement for most large species such as whales, seals and basking sharks, particularly when compared to the risk posed by some fishing activities.

However, many of these large species, known scientifically as megafauna, are protected by law in Scotland and an understanding of the potential risk of entanglement could help MRE developers and consenting authorities stay within the law.

Some larger whale species would be more vulnerable in comparison to smaller marine mammals, says the report, but where derelict fishing gear becomes attached to the mooring this could pose a risk of entanglement for a wide range of marine animals including fish and diving seabirds.

The research was carried out by the Scottish Association for Marine Science and the University of Exeter. The authors initially reviewed existing information on entanglement risks to marine megafauna posed by moorings. Then, in the absence of significant amounts of empirical data, a qualitative risk assessment was developed to assess relative risks of proposed developments, based on physical parameters of the animals and the physical parameters of the moorings.

The study provides a series of recommendations for the industry to reduce risks to animals. These include relative risk assessments, routine inspections of moorings and for developers to report to regulators any significant changes to mooring and installations. It also recommends an official process for developers to report any marine animal entanglement, and associated formal accident investigation procedure.

In addition, the report highlights a need for further investigations into the abundance of derelict fishing gear in Scottish waters, and the extent to which this becomes snagged in moorings or other structures.

Ron Macdonald, SNH director of policy and advice, said: “Our role is to provide information and advice to developers and consenting authorities on potential impacts of marine energy installations and how these impacts might be avoided or minimised. In order to do this we need to have the best available research to refer to. That’s why we commissioned this work.

“The report goes some way to reassure us that arrays of moored marine renewable devices are unlikely to pose a major threat to marine animals. But because there is still so much that is not yet fully understood, it also suggests an assessment framework to help developers and regulators consider relevant parameters when new projects are being planned.

“We very much hope that all those involved in the planning and development of moored marine renewable energy devices in Scotland will find this report useful.”