Table 5. Descriptions of predictors.

Predictor Dataset	Unit	Description	Tool Used
1. Depth	Meters	Water depth	-
2. Depth (Standard Deviation)	Meters	Dispersion of water depth values about the mean (in a 3×3 cell neighborhood)	Focal statistic function in ArcGIS's Spatial Analyst
3. Curvature (Plan or Cross-Sectional)	Concave (−) & Convex (+)	Curvature of the surface perpendicular to the slope direction (in a 3×3 cell neighborhood)	Curvature function in ArcGIS's Spatial Analyst
4. Distance to Shelf Edge	Kilometers	Distance of the centroid of each pixel to the 183 m (100 fathom) isobath	Euclidean distance function in ArcGIS's Spatial Analyst
5. Rugosity	Ratio value	Ratio of surface area to planar area (in a 3×3 cell neighborhood)	Surface Area and Ratio function in DEM Surface Toolbox
6. Slope of the Slope	Degrees of degrees	Maximum rate of maximum slope change (in a 3×3 cell neighborhood)	Slope function in ArcGIS's Spatial Analyst

Environmental variables used to predict large, medium and small fish occurrence and density. Each variable was also included in the modeling process at four additional spatial scales (i.e., using circles with radii of 25, 50, 100 and 300 m).