Marine mammals

Small marine mammals such as seals, dolphins and porpoises are the marine ecosystem top predators and therefore often threatened and vulnerable to anthropogenic impact such as pollution and overfishing. They are also sensitive to loud noise emitted to the water from eg installation of turbine foundations through pile driving.

Care must be taken in the planning of installation work to minimize impact from noise. Recent research suggests that during production phase wind farms attract small marine mammals.

Learning outcome.

After having watched this video, you should know:

• The installation phase using piling with hammers is usually harmful for marine mammals
• Mitigating measures exist such as bubble curtains
• Planning is key to avoid e.g., piling during periods when there normally are concentrations of marine mammals in the area (or during breading)
• Recent research suggest that marine mammals are attracted to OWE

Reflections

A number of piling strategies and noise reducing measures have been used to mitigate impact on marine mammals from pile driving.

“Ramp up” is one of these strategies. What is it and how can it be used?

Suggested literature

Some references may require a user account for the journal.

Harbour porpoise Phocoena phocoena abundance in the southwestern Baltic Sea. Endangered Species Research. 5, 215–223.

Harbour porpoises (Phocoena phocoena) and wind farms: a case study in the Dutch North Sea. Environ. Res. Lett. 6, 025102.

Reef effect of offshore structures on the occurrence and foraging activity of harbour porpoises. Front. Mar. Sci. 9, 980388.

Harbour seals on Horns Reef before, during and after construction of the Horns Rev Offshore Wind Farm.