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Welsh tidal turbines could be catastrophic for porpoises

A proposal for underwater tidal turbines in an area where porpoises and Risso’s dolphins come to feed and raise their newborns is threatening the West Wales Marine Special Area of Conservation and wildlife it protects.

Ynys Enlli (Bardsey Island) is a small wildlife-rich island, at the tip of the Llyn Peninsula, in North Wales. The surrounding seas are some of the most protected around the UK, including the West Wales Marine Special Area of Conservation (SAC) created to protect harbour porpoises, and Llyn Peninsula and the Sarnau SAC, a haven for bottlenose dolphins.

WDC team looking out for dolphins and porpoises around Bardsey Island
WDC team looking out for dolphins and porpoises around Bardsey Island

Your donation will help us keep porpoises safe

We’ve been studying how Risso’s dolphins and harbour porpoises use the waters around Ynys Enlli since 1999. Our research demonstrates that this special place is an important nursing ground for harbour porpoises and Risso’s dolphins and the unique tidal flows in Bardsey Sound (Swnt Enlli) are a prime feeding area. Our research was fundamental in supporting the designation of the West Wales Marine SAC.

The wave and tidal energy industry is still new, and the devices used to generate electricity still very much untested for their impacts on the marine environment and whales and dolphins. As a result, there is no data on which a reliable assessment of the impacts can be made.

What little evidence exists demonstrates a real cause for concern, in particular:

  1. Collision risk - the prospect of dolphins or porpoises swimming into the underwater devices, is extremely worrying, as the moving blades can injure or even kill them. The few studies on this have clearly demonstrated that this is a high risk in areas where harbour porpoises live.
  2. Changes to tidal flow - studies show how tidal turbines change the local tidal flow in the area around them, and the more turbines there are, the larger the area that’s affected. These changes are likely to cause changes in the movement of prey species. Harbour porpoises need to feed almost continuously to meet their energy needs and so disturbance to the fish that they eat is a massive problem for them. This could force them from their feeding grounds entirely.
  3. Noise disturbance - Noise pollution during construction of other offshore renewables developments caused harbour porpoise populations to leave the area during construction and, in many cases, not returning in their usual numbers. Tidal power infrastructure will also require construction and maintenance, resulting in increased boat traffic which could disrupt marine wildlife and increase the risk of boat collisions.
Risso's dolphins off Bardsey Island
Risso's dolphins off Bardsey Island

Well-considered marine renewable energy and any projects which mitigate the impact of climate change need to be encouraged. However, any development must be in the right place and at the right scale. This development should not go ahead in the highly protected waters of Bardsey Sound until the tidal devices are demonstrated to be of no risk to the porpoises and dolphins who make their homes here.

Read our briefing.

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Your gift will help us continue the research and campaigning that helps keep dolphins, porpoises and whales safe in UK seas

About Vicki James

Green Whale research coordinator

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