Evidence for episodic acidification effects on migrating Atlantic salmon Salmo salar smolts

Journal of Fish Biology
By: , and 

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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.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Evidence for episodic acidification effects on migrating Atlantic salmon Salmo salar smolts
Series title Journal of Fish Biology
DOI 10.1111/jfb.12763
Volume 87
Issue 5
Year Published 2015
Language English
Publisher Fisheries Society of the British Isles
Publisher location Orlando, FL
Contributing office(s) Leetown Science Center
Description 18 p.
First page 1129
Last page 1146
Online Only (Y/N) N
Additional Online Files (Y/N) N