Meeting Abstract
Life-history variation in salmonid fishes related to movement behavior represents intraspecific biodiversity important for species resiliency and ecosystem functioning. We used RFID/PIT telemetry in two Lake Superior tributaries to assess movement behaviors expressed in brook trout (Salvelinus fontinalis). Using a dataset of 650 fish tagged over four years, we detected 9-44% emigration from the streams, which likely represented the migratory (coaster) life history. Coasting behavior was not related to fish size or condition, but was predicted by a tagging location nearer to the mouth of the stream. Of the 506 fish (78%) that remained within the stream following tagging, the majority (55-60%) remained stationed close to their tagging site; however, the remainder exhibited other types of movement behavior ranging from unidirectional up- or downstream movements (20-40%) to nomadic roving (8-10%) within the study section. Mobile fish occurred throughout the streams, with a trend toward greater numbers of nomads tagged near the mouth; there was no relationship between size/condition and likelihood of mobile behavior. The proportions of fluvial movement behaviors were similar between streams and suggest more variability in movement behavior than is suggested by the migrant/resident dichotomy typically attributed to salmonids.
