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Physiological Responses of Lake Trout to Stress: Effects of Water Hardness and Genotype
Author(s) -
McDonald D. G.,
Robinson J. G.
Publication year - 1993
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1993)122<1146:proltt>2.3.co;2
Subject(s) - trout , soft water , salvelinus , acclimatization , zoology , sodium , hard water , fish <actinopterygii> , biology , fishery , chemistry , ecology , organic chemistry
We evaluated stress due to net confinement among three genetically isolated strains of juvenile lake trout Salvelinus namaycush in relation to water hardness. Changes in plasma cortisol, glucose, sodium, and chloride were used as the stress indicators. In lake trout acclimated and then confined for 8 h in hard water, plasma glucose and cortisol increased significantly (by three‐ and sixfold, respectively), reaching a plateau by 4 h, while plasma Na + and Cl – significantly decreased by about 7%. Fish transferred from hard water to soft water and then confined exhibited significantly greater changes in blood chemistry than did fish confined in hard water. This soft‐water effect on the stress response disappeared if fish were first acclimated to soft water, but full soft‐water acclimation may take at least 2 months. Comparisons of blood chemistry among three different strains of lake trout (Lake Manitou, Killala Lake, and Slate Island) revealed significant differences in their responses to confinement stress. These findings have important implications for two fish culture issues: The choice of whether to rear stocks in soft‐water versus hard‐water hatcheries, and the selection of stocks for stress resistance.