title: Evidence for episodic acidification effects on migrating Atlantic salmon Salmo salar smolts.
abstract: Field studies were conducted to determine levels of gill aluminium as an index of acidification effects on migrating Atlantic salmon Salmo salar smolts in the north-eastern U.S.A. along mainstem river migration corridors in several major river basins. Smolts emigrating from the Connecticut River, where most (but not all) tributaries were well buffered, had low or undetectable levels of gill aluminium and high gill Na(+) /K(+) -ATPase (NKA) activity. In contrast, smolts emigrating from the upper Merrimack River basin where most tributaries are characterized by low pH and high inorganic aluminium had consistently elevated gill aluminium and lower gill NKA activity, which may explain the low adult return rates of S. salar stocked into the upper Merrimack catchment. In the Sheepscot, Narraguagus and Penobscot Rivers in Maine, river and year-specific effects on gill aluminium were detected that appeared to be driven by underlying geology and high spring discharge. The results indicate that episodic acidification is affecting S. salar smolts in poorly buffered streams in New England and may help explain variation in S. salar survival and abundance among rivers and among years, with implications for the conservation and recovery of S. salar in the north-eastern U.S.A. These results suggest that the physiological condition of outmigrating smolts may serve as a large-scale sentinel of landscape-level recovery of atmospheric pollution in this and other parts of the North Atlantic region.
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.|Department of Environmental Conservation, University of Massachusetts, 160 Holdsworth Way, Amherst, MA, 01003, U.S.A.
authors.forename: J T
authors.initials: JT
authors.lastname: Kelly
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.|Organismic and Evolutionary Biology Program, University of Massachusetts, 611 N. Pleasant St, Amherst, MA, 01003, U.S.A.
authors.forename: D T
authors.initials: DT
authors.lastname: Lerner
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.
authors.forename: M F
authors.initials: MF
authors.lastname: O'Dea
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.
authors.forename: A M
authors.initials: AM
authors.lastname: Regish
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.|Organismic and Evolutionary Biology Program, University of Massachusetts, 611 N. Pleasant St, Amherst, MA, 01003, U.S.A.
authors.forename: M Y
authors.initials: MY
authors.lastname: Monette
authors.affiliation: National Marine Fisheries Service, Northeast Fisheries Science Center, Maine Field Station, 17 Godfrey Drive-Suite 1, Orono, ME, 04473, U.S.A.
authors.forename: J P
authors.initials: JP
authors.lastname: Hawkes
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.|Organismic and Evolutionary Biology Program, University of Massachusetts, 611 N. Pleasant St, Amherst, MA, 01003, U.S.A.|U.S. Forest Service, Res. Unit NE-4251, 201 Holdsworth NRC, University of Massachusetts, Amherst, MA, 01003, U.S.A.
authors.forename: K H
authors.initials: KH
authors.lastname: Nislow
authors.affiliation: USGS Conte Anadromous Fish Research Center, One Migratory Way, Turners Falls, MA, 01376, U.S.A.|Department of Environmental Conservation, University of Massachusetts, 160 Holdsworth Way, Amherst, MA, 01003, U.S.A.
authors.forename: S D
authors.initials: SD
authors.lastname: McCormick
mesh_terms: D015258:Acid Rain / Q000633:toxicity*; D000535:Aluminum / Q000032:analysis*; D025041:Animal Migration; D000818:Animals; D005880:Gills / Q000737:chemistry / Q000187:drug effects*; D008281:Maine; D009511:New England; D045483:Rivers / Q000737:chemistry; D020317:Salmo salar; D012474:Salmon; D012621:Seasons; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis*; D014481:United States
chemical_list: D015258:Acid Rain; D000535:Aluminum; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Maine; aluminium; north-eastern U.S.A; osmoregulation; pH; stress