Intrastream variation in growth rates and time of first otolith increment formation for young of the year Etheostoma simoterum (Cope) (Perciformes: Percidae)

Growth rates and otolith‐estimated hatching dates of young of the year Etheostoma simoterum were studied at four localities along an elevational gradient in the Little River, Tennessee, U.S.A. during the summer of 1983. Changes in otolith increment width and mean daily air temperature corresponded well with each other, suggesting that increments were laid down daily. Growth rate increased nearly threefold from the highest elevation site to the lowest. Median otolith‐estimated hatching dates differed by about 2 weeks between sites, and the pattern was not directly related to elevation. These data indicate that within‐stream, life‐history variation of a broadly distributed species should be taken into consideration when studying factors regulating stream fish populations along elevational gradients.