Atlantic salmon, federally protected under the Endangered Species Act, are returning to the Penobscot River in larger numbers than usual this spring. As of May 27, a total of 169 Atlantic salmon had been counted at Milford. “We have only had two years [when] salmon numbers were higher in the month of May since 1978,” said Jason Valliere, a marine resource scientist for the Maine Department of Marine Resources Division of Sea Run Fisheries and Habitat. The most productive years during that time period came in 2010, when 250 salmon returned to the river, and in 2012, when 200 fish were counted. More than 40 Atlantic salmon came through the fishway on May 22 alone. What nobody is able to predict is, what effect such a return might eventually have, if any, on the long-term survivability and viability of the resource.