Map showing density of predicted Atlantic salmon rearing habitat units in Maine.

Map showing detailed reach based predicted values for Atlantic salmon rearing habitat.

Fisheries management agencies have traditionally utilized field surveys to develop estimates of Atlantic salmon habitat in Maine rivers.  While providing detailed information, field surveys are expensive to conduct and to-date cover only a small portion of the range of historic habitat of Atlantic salmon.  A GIS-based habitat model was developed to predict the amount of Atlantic salmon rearing habitat in un-surveyed salmon rivers.  The model was developed using data from habitat surveys conducted in the Machias, Sheepscot, Dennys, Sandy, Piscataquis, Mattawmkeag, and Soudabscook Rivers.  The model uses reach slope derived from contour and digital elevation model (DEM) datasets, cumulative drainage area, and physiographic province to predict the total amount of rearing habitat within a reach.  The variables included in the model explain 73% of the variation in rearing habitat.  Maps and data from the model will help inform the proposed listing of critical habitats. This GIS based model will also be used for a variety of management activities including stocking, removing barriers, and prioritizing in-stream habitat restoration projects.  The attached maps show the extent of the area modeled by the project and detailed GIS output from the model.

Collaborators in the effort included Jed Wright and Alex Abbott of the Gulf of Maine Coastal Program, John Sweka of Northeast Fishery Center and Dan Kircheis and Tara Trinko of NOAA's Maine Field Station.