Seasonal Variation in Health and Energy Stores of Central Mudminnow Umbra Limi in Response to Watershed Land Use

Changes in land use within watersheds are known to influence fish populations in stream ecosystems, though the physiological mechanisms behind population-level changes remain elusive.  Winter is a challenging period for north temperate stream fish and thus is a logical period to evaluate how individual-level metrics related to energetic condition and health vary across systems with different land use characteristics.  We used geographic information systems (GIS) to characterize land use in six small tributaries of the St. Lawrence River and then quantified overwinter energy dynamics and fish health indices of central mudminnow Umbra limi. Using principal component analysis (PCA) to summarize physiological metrics, the effects of land use on fish condition and health were evaluated by sex and season. Male and female mudminnow were found to respond differently to both winter stress and watershed land-use, and the watershed proportion of agriculture and forest were found to have the strongest relationship with mudminnow condition.