Association Between Fall Emigration and Spawning Activity in Lake Populations of Brook Trout (Salvelinus fontinalis) of Mount Desert Island, Maine

Stone, Jennifer

FIELD WORK: Summer 1999. 'Movements of brook trout (Salvelinus fontinalis) between lakes and streams was examined on Mount Desert Island, Maine. In the summer of 1999, brook trout were marked (n = 849) using a combination of fin clips and Floy anchor tags to differentiate stream-resident brook trout from lake-resident brook trout. Two-way fish traps were placed on inlet and outlet streams during the fall, and upstream and downstream movements of brook trout were documented. Brook trout captured in the traps received temporary caudal fin clips to identify repeat migrants. Six wild brook trout and 44 stocked brook trout moved upstream from Upper Hadlock Pond into Hadlock Stream. Another 10 wild brook trout and 41 stocked brook trout moved downstream from Upper Hadlock Pond into another portion of Hadlock Stream, possibly continuing into Lower Hadlock Pond. Twenty-three brook trout moved upstream from Little Long Pond into Jordan Stream, and 75 wild brook trout and 42 hatchery brook trout moved upstream from Echo Lake into Lurvey Spring. Emigration from the three lakes coincided with brook trout spawning season and was dominated by mature brook trout in spawning color. Fall emigrants were likely searching for spawning habitat, which was unavailable within the lakes but abundant within the streams. Redds, emergent fry, and young-of-the-year brook trout were observed only in the streams, suggesting that brook trout reproduction occurred successfully in the streams and not in the lakes. A geographic information system was used to assess the spatial overlap among spawning habitat characteristics, redd locations, emergent fry locations, and young-of-the-year abundance.' /STUDY LOCATIONS:/ /MOUNT DESERT ISLAND/Hadlock Stream/Upper Hadlock Pond/Little Long Pond/Jordan Stream/Echo Lake/Lurvey Spring/