Summer Movements of Radio-tagged Arctic Charr (<i>Salvelinus alpinus</i>) in Lake Hazen, Nunavut, Canada
Radiotelemetry was used to determine whether Lake Hazen arctic charr (Salvelinus alpinus) were anadromous and to determine movements of the charr within the lake. In 1995 and 1996, 62 and 55 charr, respectively, were captured, radio-tagged, and released back into the lake. A fixed data acquisition system recorded limited movements of radio-tagged charr in the upper reaches of the Ruggles River, the only outlet from the lake to the sea, in 1995. When movements of radio-tagged charr within Lake Hazen were monitored opportunistically in 1995, most of the relocated charr were found in warmer, more productive waters associated with inflowing streams. No movements of radio-tagged charr in the Ruggles River were recorded in 1996 when the data acquisition system was operated in the lower reaches of the river. These observations supported the conclusions of a study of Lake Hazen charr otolith strontium distribution that Lake Hazen charr were non-anadromous. The Ruggles River may be a detriment to anadromous behaviour because of its length (ca. 29 km), velocity (up to 2.25 m/s), and the year-round presence of aufeis (layered ice buildup). In summer, instead of migrating to the sea to feed, Lake Hazen charr appear to move to feed on abundant prey found in areas where inlet streams enter the lake.