Impacts of stocked splake on lake trout and brook trout fisheries

Session: Restoration and Management of Great Lakes Fishes (2)

Liz Tristano, Wisconsin Sea Grant and Wisconsin Department of Natural Resources, [email protected]
Brad Ray, Wisconsin Department of Natural Resources, [email protected]
William Fetzer, Wisconsin Department of Natural Resources, [email protected]
Titus Seilheimer, Wisconsin Sea Grant, [email protected]

Abstract

Fish stocking in the Great Lakes is a common means by which management agencies may enhance or create fisheries.  In Lake Superior, a variety of species have been stocked, including the lake trout x brook trout hybrid, splake (Salvelinus namaycush x S. fontinalis), with variable success.  Splake stocking began in response to declining lake trout populations in the 20th century, but the potential for introgression with its parent species suggests that splake may threaten recovering lake trout, as well as to brook trout populations.  This study reviews the history of splake stocking and examines the risks and benefits of stocking splake into Lake Superior, including probability of introgression, competitive interactions between splake and brook or lake trout, splake harvest and economic returns, and long-term impacts to Lake Superior fisheries.  Preliminary findings suggest that splake may reproduce with both parental species and with other splake, potentially to the detriment of brook and lake trout reproduction.  Moreover, recreational returns of splake appear to be low, with a return to creel of 0.00847 ± 0.00572 splake harvested/splake stocked.  Moving forward, it is important to fully understand splake impacts on brook and lake trout and the risks of stocking splake into Lake Superior waters.