Offshore Environmental Impact Studies: seabirds

Areas with high potential for the development of offshore wind energy have already been defined (ZAPER); 19 polygons, 5000 km², 0.46% of Spanish waters. An opportunity not to incur the same scale errors as when deploying renewable energy on land. Namely; the strategic environmental assessment of the Maritime Spatial Planning Plan and informed decision-making with the environmental impact assessment of projects.

The deployment of wind energy in the sea depends on the wind speed (the resource), the depth of the water (the wind turbines are installed on the continental shelf) and the waves (the stability of the wind farm). Seabirds and wind turbines occupy the continental shelf, with calm waters and wind. If photovoltaic solar plants affect agrosteppe birds due to habitat loss and onshore wind farms affect birds of prey due to direct mortality; the threat to seabirds is also the collision with wind turbines. And the barrier effect, because wind turbines would interrupt the movement of seabirds.

A sensitivity map is needed for seabirds outside exclusion zones (protected natural areas and Natura 2000, including IBA), depending on breeding colonies, feeding areas and also migratory corridors. Seabirds are strategists of the K (longevity, low productivity, population size similar to carrying capacity); recruitment would not compensate for high unnatural mortality. Adult survival is the demographic parameter that determines the viability of seabird populations. Therefore, the impact of a poor deployment of offshore wind energy would be critical for already threatened seabirds such as Balearic shrews (Puffinus Mauretanicus), Mediterranean Cinderella (Calonectris Diomedea) and Atlantic (C. Borealis), Audouin's seagull (Ichthyaetus Audouinii) or Bulwer's petrel (Bulweria Bulwerii).

In addition, the condition to fishing must be evaluated; if a change in water currents would affect the availability of prey for seabirds. And also how noise pollution would impact fish and cetaceans during construction and also during operation, due to the transmission of noise from the turbine to the water.

The industrial occupation of a natural space must always comply with the precautionary principle. And, due to lack of experience, offshore wind energy projects need adaptive management; a structured and iterative decision-making process to reduce uncertainty.

At Ideas MedioAmbiental, we prepare environmental impact studies for offshore wind farms to reconcile the deployment of renewable energy and the conservation of marine biodiversity.

Iván Salgado, Biodiversity