Ecophys.Fish, an ecophysiological framework to simulate fish growth in time-varying environments, was parameterized for two sole species, Solea solea (Linnaeus, 1758) and Solea senegalensis Kaup, 1858. The model gave reliable predictions of soles' growth and metabolic rates from published data under controlled environments. Differences in model parameters reflected specie's different environmental optima and were in accordance with their distributional range northern range of S. solea and a southern range of S. senegalensis. Field application of this model to resolve the effects of varying habitat conditions on juvenile soles' growth in the Tagus estuary (Portugal), during the spring-summer period from 2003 to 2006, highlighted spatial and temporal differences in soles' metabolic scope for growth and estimated growth rates. Higher growth estimates were obtained for S. solea and S. senegalensis in Vila Franca de Xira during 2006, and for S. senegalensis in Alcochete during 2003, 2004 and 2006, and were fairly well explained by natural variation in abiotic conditions. Overall, the Ecophys.Fish model gave accurate field predictions of each sole species' growth rate and proved to be a useful tool for monitoring and assessment of habitat quality for juvenile sole. (C) 2009 Elsevier B.V. All rights reserved.