Inferring littoral substrates, fish habitats, and fish dynamics of Lake Tahoe using IKONOS data

High spatial resolution IKONOS satellite imagery was used to map surface and submerged littoral substrates in Lake Tahoe, California and Nevada, USA. The satellite data were radiometrically corrected for varying water depth and classified in different substrate types (i.e., sand, gravel, cobble, and boulder.) The overall accuracy achieved was 86% for submerged substrate mapping and 81% for shoreline substrates. The derived substrate types were translated into three classes of fish habitats (spawning, feed and cover, and marginal) to improve the spatial extent and detail of existing fish habitat spatial datasets used for land-use planning and regulatory purposes. Selected fish species distribution and abundance were predicted from the derived substrate map and an existing lake bathymetry map by linking remotely sensed measurements with in situ fish observations. The results suggest that feed and cover habitats of native fish and spawning grounds are limited to distinct areas around the lake, which, for the first time, were identified spatially in a consistent way. Management and land-use actions should consider additional focus on these areas if the natural littoral fish habitat characteristics for Lake Tahoe are to be maintained.