Thermal sensitivity of growth, food intake and activity of juvenile brown trout.

Growth rate, food intake and activity of juvenile brown trout (Salmo trutta L.) were studied at 10 constant temperatures (2.6-22.3 degrees C) and using eight full-sib families. We found between-family differences in growth rate but not significant temperaturexfamily interaction. The effects of temperature were well described by polynomial regressions that allowed the calculation of optima, performance breadths and thermal limits. The obtained values were noticeably higher and the performance breadth wider, than previously reported data for the species.