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, largely due to the region’s inaccessibility and lack of baseline studies from most areas. 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 30km long and up to 10km wide. This study is primarily based around the Huinay Scientific Field Station. Since vessels equipped with a multibeam echo sounder are unavailable in this region, an autonomous underwater vehicle (AUV) was utilized for these surveys. The AUV survey data can provide the basic information to develop habitat suitability modeling and, with repeat surveys, measure the spatiotemporal variability in benthic communities, including the impacts of any anthropogenic activity (from aquaculture or shellfish harvesting in the fjord). Habitat maps were produced at two sites within Comau Fjord: Huinay Bay and Cross Huinay, applying the Teledyne Gavia AUV which uses a 500kHz GeoSwath+ sonar. A total of 16 habitats were identified from the combined analysis of sidescan sonar, bathymetry, and seabed images. The habitats were graded as poor and were assessed as declining over the last 5 years.