Habitat Mapping in the fjords of the Chilean Patagonia using an Autonomous Underwater Vehicle

Habitat information from the fjordic environments of the Chilean Patagonia is sparse, due largely in part to the regions inaccessibility and therefore a lack of baseline studies. Here we present the results of a preliminary mapping study in Comau Fjord. The fjord is located within the Los Lagos region of Chile and is 30 km long and up to 10 km wide. This study is primarily based around the Huinay Biological Station south of Hornoprien. Vessels equipped with a multibeam system are uncommon in this region, so for this study we utilised an autonomous underwater vehicle (AUV). AUVs offer a novel habitat mapping tool as they are compact, portable and capable of being deployed from ‘vessels of opportunity’. AUV survey data can provide the basic information to develop habitat suitability modelling and measure the spatio-temporal variability in benthic communities, including the impacts of any anthropogenic activity (primarily from sites of aquaculture in the fjord). The Teledyne Gavia AUV uses a 500 kHz GeoSwath+ sonar providing bathymetry, side-side and a camera for photography.
Habitat maps were produced at two sites within Comau Fjord; Huinay Bay and Cross Huinay. A total of 16 habitats were identified from the combined analysis of side scan sonar, bathymetry and seabed images. The habitats were graded as poor and were assessed as declining over the last 5 years.