His professional marine mammal survey experience, however, originates from participating in the 2005 survey 'Small Cetaceans in the European Atlantic and the North Sea' (SCANS II) on the Faroese ship West Freezer covering the Northern part of the North Sea. Here Troels worked both as a primary observer and tracker during this dual platform survey effort. Nothing substitutes experience, and valuable knowledge of the software used both concerning everyday use as well as trouble shooting whenever hardware and software malfunctions arose. In the summer of 2007 Troels joined the 'Trans North Atlantic Sightings Survey' (TNASS) as a primary observer for the Icelandic Marine Research Institure. He worked on the Faroese longliner Jakup B sailing more than 3000 nm in the central North Atlantic south of Iceland. TNASS was conducted with the same protocol as SCANS II
Valuable experience with demanding software during long hours of persistent effort was gained.
Between seasons he has also occupied himself with various freelance scientific challenges in the field of marine mammals covering a multitude of aspects from photo identification of dolphins and large whales as well as participating in research on the accidental bi-catch of Harbour Porpoises in commercial fishing gear.