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The effect of temperature, flow, density and disease on smallmouth bass (Micropterus dolomieu) early life growth rate

Rebecca S.M O'Brien·Megan K. Schall·Geoffrey Smith·Kelly L. Smalling·Tyler Wagner
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Abstract

Individual growth rates of fish are influenced by gradually changing environmental conditions and rapid-onset events. However, there is a paucity of information on drivers of spatiotemporal variability in growth rates of fishes across large spatial extents. Using a 36-year dataset of smallmouth bass ( Micropterus dolomieu ) length-at-age data across 10 river reaches in Pennsylvania, USA ( n = 54,068 individuals), we estimated annual early life growth rates (mm year −1 ) and assessed the effects of relative abundance, summer temperature, summer streamflow rate and a disease outbreak on growth rate. We found that temperature had a positive effect on growth rate, varied spatially, and had a stronger effect in diseased reaches. There was also evidence for an impact of disease on early life growth through density-dependent mechanisms, with growth rates increasing from ∼85 to 101 mm·year −1 following disease-related decreases in abundance. This study adds to our understanding of the factors that shape early life growth, including rapid-onset events like disease which can have immediate and lasting effects on growth rate trajectory.

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Ecology of Freshwater FishArticle

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Rebecca S.M O'Brien, Megan K. Schall, Geoffrey Smith, Kelly L. Smalling, Tyler Wagner. 2026-08-28. The effect of temperature, flow, density and disease on smallmouth bass (Micropterus dolomieu) early life growth rate. https://doi.org/10.1111/eff.70063

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Article subjectEcology of Freshwater Fish subjectPennsylvania placeUnited STates place

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