Are Larvae and other Planktonic Organisms at Risk from Tidal Energy Development?

As tidal energy development ramps up in Europe and North America, questions have been raised about the potential for turbine blades to strike marine mammals, fish, and other marine organisms. Less attention has been paid to potential threats to smaller planktonic organisms such as the larvae of fish, lobster, and the zooplankton that spend their lives floating in moving ocean water.  A small group of experts came together recently to explore whether larvae and zooplankton might be at risk from tidal turbines.

Lobster and fish larvae are most commonly buoyant and distributed by tidal currents, waves, and other water movements that allow them to disperse widely before they morph into their final adult forms and settle to the sea floor or move towards their preferred habitats. Similarly, zooplankton that spend their entire lives in open water are transported largely via water currents. Tidal turbines sited in the estuaries and coastal waters to generate renewable energy will intersect with the movement of some larvae and zooplankton. This expert forum addressed concerns raised that larvae of commercially and recreationally important species, as well as those that form the base of the marine food web, could be harmed by the operation of tidal turbines.

The experts examined issues of scale – whether the size and pressure levels associated with tidal turbines are likely to affect larvae and zooplankton, and whether the number of larvae that might be harmed are large enough to alter populations of commercially important species.  The conclusion was that tidal turbines would be unlikely to pose a risk to these small size classes of marine life.  For more information, view and listen to the presentations and hear the discussion among the experts, as part of our Annex IV expert forum series.

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Tidal Energy