Dogger Bank Survey: harbour porpoises, moonlit sightings and owls!

Saving fuel and making the best of light winds. Six days in and we have completed two of our smaller survey blocks, the first close to the Hornsea wind farm and the second covering the UK proposed Special Area of Conservation over the Dogger Bank. Each block was covered by several zigzag transect lines surveying a total distance of 600 km. During the days with good weather there have been many sightings of harbour porpoises, mostly in small groups of one or two, although we did also have an encounter with a larger group of 5 animals. Several grey seals and at least two minke whales have also been encountered during daylight observations as well as some bow riding white-beaked dolphins spotted in the moonlight on night watch. Many bird species have also been seen, mostly kittiwakes, fulmars, gannets, guillemots and puffins, although we have had two owl sightings.

Computer screen grab of Harbour porpoise clicks: Showing HP clicks detected during the Dogger Bank survey. The red triangles show each click and a clear bearing can be seen as the porpoise passes. Surprisingly, for November, and the North Sea, the survey has been relatively calm with only one day of rough weather when visual observations were not possible from the A-frame so far. This is when the acoustic side of the survey becomes especially important, with clear detections of harbour porpoises even during rough sea states. Additionally, the acoustic monitoring has allowed further understanding of the background noise levels experienced by marine mammals in the North Sea, as seismic survey noise has been heard for long periods over several days during our survey to date.

At the moment we are heading back down south to start our larger survey block which will cover the whole Dogger Bank area, from the east coast of England into Danish, Dutch and German waters. The weather looks promising for the next few days, and as we were treated to a beautiful winter red sunset tonight, we hope it will be “sailor’s delight” with many sightings to come tomorrow.

-- AM

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Brian Sharp, Emergency Relief Officer, Stranding Coordinator
Manager, Marine Mammal Rescue and Research
Dr. Maria (Masha) N. Vorontsova, Senior Advisor to the IFAW Marine Conservation
Senior Advisor to the IFAW Marine Conservation Program
Matt Collis, Director, International Policy
Director, International Policy
Patrick Ramage, Program Director, Whales
Program Director, Marine Conservation