Diel and seasonal white sturgeon (Acipenser transmontanus) movements in relation to Columbia River temperatures

摘要

Radio-tagged white sturgeon, 12 with temperature sensing transmitters, were monitored, from April through December 1977 in the free-flowing Hanford Reach of the Columbia River. River temperatures appeared to influence diel and seasonal sturgeon movements. In summer, from late afternoon to late evening, sturgeon environmental temperatures were higher than main current river temperatures. Sturgeon position determinations suggested movements into warmer inshore areas as darkness approached, perhaps to feed. After midnight, recorded sturgeon environmental temperatures declined, indicating movements back to cooler, main channel areas, especially after sunrise. Movements farther than 2 km from release sites did, not occur unless water temperatures were above 13(degrees)C.