Migratory Behavior of Juvenile “Coaster” Brook Trout Stocked into Whittlesey Creek, WI: a Lake Superior Tributary

“Coaster” brook trout Salvelinus fontinalis, a migratory form of brook trout historically abundant in Lake Superior and its tributaries, has declined since the early 1900s due to overharvest and habitat alterations throughout the basin. Over the past decade, the U.S. Fish and Wildlife Service has stocked eggs, fingerlings (2 in), yearlings (5 in), and adult (>10 in) coaster brook trout into Whittlesey Creek, WI as one of several conservation actions identified in a multi-agency effort to restore depleted stocks in Lake Superior and its tributaries.  Since spring 2008, half-duplex Passive Integrated Transponder (PIT) tag technology has been used to track movement and migratory behavior (emigration and immigration) of both wild and stocked yearling brook trout. To date, both stocked and wild yearling brook trout exhibit similar seasonal emigration patterns, with peak periods of movement occurring in either the fall (October/November) or spring (April/May) of a given year. Likewise, both wild and stocked yearling brook trout exhibit a similar diurnal pattern of movement with the majority of movements both within and out of the stream occurring between 2000 and 0200 hours.  To date, five PIT tagged yearlings from the 2008 stocking event have returned to Whittlesey Creek as sexually mature adults: one 16-months post-stocking, one 2 years post-stocking, and two 2.5 years post-stocking.