| Abstract: | Episodic acidification resulting in increased acidity and inorganic aluminum (Ali) is known to impact anadromous salmonids and has been identified as a possible cause of Atlantic salmon population decline. Sensitive life-stages such as smolts may be particularly vulnerable to impacts of short-term (days–week) acid/Al exposure, however the extent and mechanism(s) of this remain unknown. To determine if Atlantic salmon smolts are more sensitive than parr to short-term acid/Al, parr and smolts held in the same experimental tanks were exposed to control (pH 6.3–6.6, 11–37 μg l−1 Ali) and acid/Al (pH 5.0–5.4, 43–68 μg l−1 Ali) conditions in the lab, and impacts on ion regulation, stress response and gill Al accumulation were examined after 2 and 6 days. Parr and smolts were also held in cages for 2 and 6 days in a reference (Rock River, RR) and an acid/Al-impacted tributary (Ball Mountain Brook, BMB) of the West River in Southern Vermont. In the lab, losses in plasma Cl− levels occurred in both control parr and smolts as compared to fish sampled prior to the start of the study, however smolts exposed to acid/Al experienced additional losses in plasma Cl− levels (9–14 mM) after 2 and 6 days, and increases in plasma cortisol (4.3-fold) and glucose (2.9-fold) levels after 6 days, whereas these parameters were not significantly affected by acid/Al in parr. Gill Na+,K+-ATPase (NKA) activity was not affected by acid/Al in either life-stage. Both parr and smolts held at BMB (but not RR) exhibited declines in plasma Cl−, and increases in plasma cortisol and glucose levels; these differences were significantly greater in smolts after 2 days but similar in parr and smolts after 6 days. Gill NKA activity was reduced 45–54% in both life-stages held at BMB for 6 days compared to reference fish at RR. In both studies, exposure to acid/Al resulted in gill Al accumulation in parr and smolts, with parr exhibiting two-fold greater gill Al than smolts after 6 days. Our results indicate that smolts are more sensitive than parr to short-term acid/Al. Increased sensitivity of smolts appears to be independent of a reduction in gill NKA activity and greater gill Al accumulation. Instead, increased sensitivity of smolts is likely a result of both the acquisition of seawater tolerance while still in freshwater and heightened stress responsiveness in preparation for seawater entry and residence. |
| Genre: | Article |
| ProdID: | 70033453 |
| Citation Author: | Monette, M. Y.; McCormick, S. D. |
| Citation Contributing Office: | Leetown Science Center |
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| Citation End Page: | 226 |
| Citation Issue: | 2 |
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| Citation Language: | English |
| Citation Larger Work Title: | Aquatic Toxicology |
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| Citation Phsyical Description: | 11 p. |
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| Citation Publisher: | Elsevier |
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| Citation Search Results Text: | Impacts of short-term acid and aluminum exposure on Atlantic salmon (Salmo salar) physiology: A direct comparison of parr and smolts; 2008; Article; Journal; Aquatic Toxicology; Monette, M. Y.; McCormick, S. D. |
| Citation Start Page: | 216 |
| Citation Volume: | 86 |
| Citation Year: | 2008 |
| Type: | citation/reference |
| Text: | Impacts of short-term acid and aluminum exposure on Atlantic salmon (Salmo salar) physiology: A direct comparison of parr and smolts; 2008; Article; Journal; Aquatic Toxicology; Monette, M. Y.; McCormick, S. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/j.aquatox.2007.11.002 |
| Date Other: | Tue, 1 Jan 2008 00:00 -0600 |
| Publisher: | Elsevier |
