Quantitative assessment of invasive species in lacustrine environments through benthic imagery analysis

A.L. Forrest, M.E. Wittmann, V. Schmidt, N.A. Raineault, A. Hamilton, W. Pike, S.G. Schladow, J.E. Reuter, B.E. Laval, A.C. Trembanis

Limnol. Oceanogr. Methods 10:65-74 (2012) | DOI: 10.4319/lom.2012.10.65

ABSTRACT: The establishment, spread, and impact of the invasive bivalve Corbicula fluminea (C. fluminea), in Lake Tahoe threatens native species distribution in the lake and, potentially, has long-term implications for water clarity. In 2009, UBC-Gavia, an Autonomous Underwater Vehicle (AUV), was used as a platform to collect georeferenced imagery of the benthic regions of Lake Tahoe to determine the lake-wide distribution of C. fluminea. Images were collected in water depths less than 10 m at an approximately constant height above the bottom of 2 m. Images were processed using a semi-automated procedure to determine the ratio of the lakebed covered by exposed C. fluminea shells. A visual review was conducted on a subset of the images to determine presence of filamentous algae that has been observed in association with C. fluminea. Nearly 100 km of shoreline was covered over a 7-d period, and C. fluminea presence was reconfirmed in 4 regions and additional 10 regions identified.