Stream Attributes and Habitat Intrinsic Potential Model Results to examine Freshwater Habitat Potential for Chinook Salmon in the Yukon and Kuskokwim River Basins, Alaska

Chinook Salmon (Oncorhynchus tshawytscha) are an important commercial, subsistence, and recreational fishery resource in Alaska, and recent population declines have resulted in closures of some Chinook Salmon fisheries. Research into environmental factors involved in the decline of salmon stocks has exposed information gaps regarding fine-scale freshwater habitat quality known to influence Chinook Salmon productivity. We developed spatially-explicit intrinsic habitat potential models for Chinook Salmon freshwater spawning and rearing life-stages based on geomorphic stream network attributes (e.g., gradient, mean annual flow, valley bottom width). Model predictions were applied to individual stream reaches and summarized across synthetic stream networks derived from high-resolution (5-meter) digital elevation models covering the Yukon River drainage west of the US-Canada border and the entire Kuskokwim River drainage (total stream length ~667,000 km across 1.3 million km2 area). Vector spatial datasets include unique reach contributing area (uRCA) and unique reach contributing area valley bottom (uRCA VB) polygons, and confluence to confluence streamline edges derived from the NetMap synthetic streamlines product. Tabular data includes a collection of stream attributes summarized by uRCA or uRCA VB polygons, and habitat model results derived from these stream attributes. See metadata records for individual data elements for a description of input sources, software
environments, data quality, processing steps, and attribute information. Approximately 87,500 and 39,500 stream km were predicted to represent moderate to high (index scores 0.6-1.0) Chinook Salmon rearing and spawning habitat suitability, respectively. Our high-resolution, spatially explicit dataset provides many options for summarizing and visualizing habitat suitability across areal units (e.g., river basins, land management boundaries) and assessing the potential for high suitability habitats outside the known distribution of Chinook Salmon at scales useful for managers and the research community.