Identification of patterns in community structure is a central theme in freshwater ecology. Our objectives were to identify temporal patterns in fish assemblages from 1980 to 2010 in the West Fork White River in east-central Indiana using the Malthusian growth model and determine whether changes in the population growth rate parameter were related to Grinnellian niche breadth. We studied local-scale fish assemblages in a Midwestern United States river at 16 sites for a period of 30 years. We used a hierarchical model to estimate population abundance parameters of the Malthusian growth model. Niche breadth was incorporated as a model parameter to explain variation in the population growth rate. Parameters of the model were fit using Bayesian inference. We identified notable changes in the fish assemblages; however, the patterns for temporal trends in individual species abundances were not conserved across sites. Decreasing trends were observed in longear sunfish, striped shiner, white sucker, central stoneroller, common carp and creek chub while bluegill and mimic shiner increased in abundance. Longear sunfish was the only species that exhibited the same trend in abundance for all sites. Niche breadth was inversely related to the population growth rate at sites adjacent to low-head dam impoundments. We suggest that the presence of multiple impoundments has resulted in a fragmented series of fish assemblages. [ABSTRACT FROM AUTHOR]