Cumulative effects thresholds for arctic grayling in the Wapiti River watershed

• Main Author: Norris, Adam Paul
• Other Authors: Sullivan, Michael, Moran, Johnathan
• Language: unknown
• Published: 2013
• Subjects: Arctic Grayling; Dissolved oxygen diurnal cycles; Land use; Water-quality based habitat; Fisheries management; Arctic; Arctic grayling; Thymallus arcticus
• Online Access: http://hdl.handle.net/10170/553

Intensity and types of land use have changed rapidly in the last century and in north-western Alberta this has coincided with the decline of Wapiti River watershed Arctic Grayling ( Thymallus arcticus ) populations. Data on diurnal dissolved oxygen (DO), chemical and physical stream habitat data were collected in nine sub-watersheds of the Wapiti River with historically abundant Arctic Grayling populations. Levels and fluctuations of DO and temperature were related to the status of populations; five of the nine streams had higher temperatures and lower DO during summer, anoxic conditions during winter and extirpated populations. Amount of disturbed land and road density within sub-watersheds were inversely related to DO levels and population status. Cumulative effects modelling suggests a possible mechanism for these relationships is increased phosphorous runoff, leading to impaired habitat. These relationships and thresholds may be used as a management tool to maintain or restore Arctic Grayling and other stream fishes.