Application of a Bioenergetics Model for Brown Trout to Evaluate Growth in Southeast Minnesota Streams

摘要: We examined the influence of water temperature, diet, and feeding sites on growth differences brown trout Salmo trutta in southeast Minnesota streams. Streams were classi- fied as having either fast or slow based back-calculated lengths at age incremental measurements from scales collected 2002 2003. Mean fast-growth streams exceeded 141 mm 1, 229 2, 289 3. In slow- streams, mean did not exceed 127 208 268 The frequency was low both stream groups, although possibly higher Water temperatures significantly warmer summer somewhat cooler winter. used a Wisconsin-style bioenergetics model for to independently test effects temperature holding other parame- ters constant. Differences regime alone sufficient explain growth, and, fact, predicted slower summer. Different diets resulted differing weight gains when held constant; with high- est energy densities always greatest gains. For younger cohorts, diet items high included amphipods mayflies (Ephemeroptera). Estimated con- sumption rates increased temperatures. Our data suggested that among likely due prey availability, more energy-rich di- ets available hypothesize availability are mediated by