Shifts in sauger spawning locations after 40 years of reservoir ageing: influence of a novel delta ecosystem in the Missouri River, USA.

摘要: To determine how reservoir ageing affects sauger Sander canadense spawning locations in Lewis and Clark Reservoir, we quantified riverine habitat determined during recent years (2003–2004) compared these results to historic (1950–1966) conditions locations. The above the reservoir, which was historically homogeneous, has developed into two distinct areas: upstream remnant river reach, characterized by a main channel, cold clear water from hypolimnetic discharge downstream delta section, abundant side channels backwater areas is warmer more turbid than reach. Sauger have shifted markedly last 50 years. spawned upper reaches of this system, near Fort Randall Dam. However, 2003, found that lower reach avoided This shift likely occurred concomitantly with development novel habitat. functions similarly system (warmer temperature, turbidity, active meandering, complex habitats, etc.), indicating prefer spawn function. Thus, future management activities intended enhance populations should focus on restoration function, such as provided emerging deltas, may mimic pre-impoundment Missouri River. Copyright © 2008 John Wiley & Sons, Ltd.