Use of an Unmanned Aerial Vehicle Equipped with a Digital Camera As a Visual Sampling Tool in Coastal Habitats

We used an unmanned aerial vehicle (UAV) equipped with a digital camera to evaluate its effectiveness as a sampling tool in shallow Great Lakes coastal habitats. The six-bladed UAV carried a digital camera with a 36.3 MP sensor and a 50 mm prime lens, and was programmed to take one to two images sec^-1. Captured images were stitched together electronically to create a detailed mosaic. We found that when flown at an altitude of 30 m, objects could be distinguished at 1 cm resolution, and their size could be determined by placing objects of known length in the flight path. We could sample visually depths up to two m, however, we were working in clear water conditions. Mosaics revealed that the approach could be used to create extremely fine scaled habitat maps. Adult Common Carp showed no avoidance of the hexacopter, and could be identified and counted accurately. Our pilot study suggests that this technology would be ideal for redd counts, obtaining density estimates of large or wary adult fish in shallow habitats, and sampling places where direct access to habitats is problematic.