Post-Dam Removal Movements of Upstream Migrating Adult Atlantic Salmon in the Lower Penobscot River, ME

As part of the Penobscot River Restoration Project (PRRP), Great Works (rkm 60) and Veazie (rkm 48) Dams were removed from the Penobscot River, ME, making Milford Dam (rkm 62) the first impediment to fish upstream migration.  The PRRP is expected to increase upstream habitat access for anadromous species, including federally endangered Atlantic Salmon. This increase is dependent upon successful passage at a newly constructed fish lift at Milford Dam, as nearly all suitable spawning habitat is located upstream of Milford. In 2014, twenty three adult fish were captured at Milford, radio and PIT tagged, and displaced downstream in tidal reaches below the removed dams to track their upstream migration through the lower Penobscot River. Movement rates through the Veazie or Great Works Dam remnants were comparable to open river reaches. Fish did experience delays at Milford Dam (0.2 to 75.1 days;  median=3.84). 91.3% of tagged fish successfully passed Milford Dam. Tagged fish displayed three general movement patterns after directed upstream  movement: i)  delay near Milford Dam followed by passage, ii)  rapid passage at Milford Dam, or iii) fallback from Milford followed by movements likely associated with thermal selection.