Comparative analysis of new digital capture methods for visual aerial porpoise and seabird monitoring in the German Exclusive Economic Zone of North Sea and Baltic Sea (PhoViComp)



The German Federal Agency for Nature Conservation (Bundesamt für Naturschutz, BfN)


Dr. Esther Rickert (project coordinator), Dr. Kai Borkenhagen, Dr. Nele Markones, Prof. Dr. Stefan Garthe

Project term:

July 2016 - December 2018


Marine mammals and seabirds are important elements of marine ecosystems. Due to various anthropogenic impacts such as ship traffic, fishing industry and the expansion of offshore wind farms marine mammals and seabirds face more and more restrictions in their natural habitat. To ensure an effective protection of these animals it is essential to monitor population densities as well as spatial distribution patterns. In the German North and Baltic Seas these data are recorded within different monitoring projects via ship and aircraft based surveys.

In offshore wind farms observer-based aerial surveys have recently been forbidden for security reasons due to their low altitudes. An alternative choice to observer-based surveys are digital survey methods that are performed in significantly higher altitudes. Digital aerial survey methods are relatively new and still need evaluation.  

Project outline:

Within the project PhoViComp a direct comparison between a video- and photo-based digital aerial survey transect method will be made. Both methods can simultaneously record marine mammals and seabirds. One very important criteria of the project is to test if the method meets the requirements of the large scale German marine vertebrate monitoring programme.

Comparison surveys will be performed in specific areas of the North and Baltic Sea. In the selected North Sea area (west of Amrumbank) harbour porpoises are abundant especially during summer and divers as well as common guillemots and razorbills can be expected during spring. The selected Baltic Sea area (east of Rügen) is known for large concentrations of sea ducks (long-tailed ducks, common scoter, velvet scoter) and therefore a representative survey site for large and mixed bird flocks. Furthermore, the area also allows testing the detectability of small inconspicuous species (black guillemot, slavonian grebe). In this survey area parallel comparative data are collected by means of an observer-based ship survey.  

The obtained material is also used to make first assessments of species-specific detectability in digital survey methods.


Aerial Survey