Seasonal changes in the physiology of brook trout, Salvelinus fontinalis (Mitchill), in a sub‐Arctic river system

• Published in: Journal of Fish Biology
• Main Authors: Cunjak, R. A., Power, G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1986
• Subjects: Arctic; Koksoak River
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1986.tb04945.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1986.tb04945.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1986.tb04945.x

Brook trout, Salvelinus fontinalis , were sampled from two sites on the Koksoak River system in northern Quebec to determine seasonal physiological changes in hematology and proximate body composition. Water content increased over the winter at both sites, whereas body lipids decreased. The relationship was most pronounced in the anadromous trout of the Caniapiscau River compared with the smaller resident trout of a tributary stream. Serum protein levels decreased significantly over the winter with the greatest depletion being realized by Caniapiscau River trout. Despite the severity of the winter stream environment in the north, the extent of depletion was similar to that encountered in temperate latitudes, suggesting compensatory physiological mechanisms within the species’ latitudinal range. By mid‐summer both populations had restored their depleted energy stores, especially the anadromous trout which accumulated the greatest amount of lipids after feeding in the estuary. Serum glucose levels were maintained at high levels during the winter, then declined in the summer. Differences between the two sites for the degree of physiological change are discussed in relation to specific overwintering strategies and life history variation.