Daily length-frequency data were used to assess the effect of water temperature and salinity on the in situ summer growth of age-1 broad whitefishCoregonus nasuscollected in the Sagavanirktok River delta in arctic Alaska. Summer growth patterns for the years 1982 and 1985–1989 were approximated as piecewise linear functions whose slopes were regressed against mean surface water temperature and salinity in the delta for each designated period. Multiple-regression analysis indicated that growth rate was significantly correlated with water temperature (P< 0.01) but not with salinity (P= 0.28). The growth-temperature relationship was described by both a linear and a polynomial function. Both functions were used to generate growth patterns for each of the six study years, based upon water temperature, The linear function modeled the 6 years of growth data with a mean absolute error of 2.1 mm (SD, 1.5 mm) and the polynomial function with a mean absolute error of 3.8 mm (SD, 3.0 mm). If independent verification proves the model to be applicable to other coastal regions of northern Alaska and Canada, the model would have direct application in assessing impacts of oil and gas development in the Arctic.