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008150406s2000    onc     ob   f000 0 eng d
040 |aCaOODSP|beng
041 |aeng|bfre
043 |an-cn---
0861 |aFs70-1/2000-050E-PDF
1001 |aFarmer, Gilbert J.
24510|aEffects of low environmental pH on Atlantic salmon (Salmo salar L.) in Nova Scotia |h[electronic resource] / |cG.J. Farmer.
260 |aOttawa : |bFisheries and Oceans Canada, |c2000.
300 |a7 p. : |btables.
4901 |aCanadian Stock Assessment Secretariat research document, |x1480-4883 ; |v2000/050
504 |aIncludes bibliographical references (p. 5-6).
520 |aAcidic rivers in Nova Scotia have low concentrations of Ca++ (calcium) and high concentrations of dissolved organic matter and total dissolved aluminum. Dissolved organic matter binds to aluminum to form organic aluminum complexes which are not toxic to Atlantic salmon. Increased H+ ion concentrations (acidity) coupled with the low concentrations of Ca++ have caused the mortality of salmon in Nova Scotia. When pH ≤ 5.0, the active uptake of Na+ (sodium) and C1- (chloride) across the gill epithelium is reduced and the passive efflux is increased resulting in the net loss of both ions. The increased passive efflux of ions results from the displacement of Ca++ from binding sites on the gill epithelium by H+. The loss of ions results in a shift of water from the extracellular fluid volume to the intracellular fluid volume causing a reduction in blood volume. The reduced blood volume and an increase in hemotocrit causes an increase in blood viscosity which results in circulatory system failure. Sensitivity of the various salmon stages to low pH can be summarized in the following order of decreasing sensitivity: fry>smolt>small parr>alevin>egg. Thus, significant mortality (19-71% of fry occurs at a pH of about 5.0. Mortality of smolts also occurs at a pH of 5.0 but the rate is lower (1-5%). Mortality of parr and smolts is relatively great (72-100%) when pH declines to the 4.6-4.7 range. Mortality of eggs and alevins does not begin until pH declines below 4.8.
69207|2gccst|aFisheries resources
69207|2gccst|aSalt water fish
69207|2gccst|aRivers
69207|2gccst|aAcid rain
69207|2gccst|aFisheries management
7101 |aCanada. |bDepartment of Fisheries and Oceans.
7102 |aCanada.|bCanadian Stock Assessment Secretariat.
830#0|aCanadian Stock Assessment Secretariat research document,|x1480-4883 ; |v2000/050|w(CaOODSP)9.507740
85640|qPDF|s39 KB|uhttps://publications.gc.ca/collections/collection_2015/mpo-dfo/Fs70-1-2000-050-eng.pdf