Present address: Pacific Ganw/ish Fni/nda/ion 



P.O. Box 25115 



Himi>lulu.HI96H25 



Belle VV. Bariich Institute for Marine Biology and 

 Coastal Research and Department of Biology 

 University of South Carolina 

 Columbia. SC 29208 



J. M. DEAN 



DIEL AND SEASONAL MOVEMENTS OF WHITE 



STURGEON. ACIPENSER TRANSMONTANUS, 



IN THE MID-COLUMBIA RIVER 



The white sturgeon, Acipenser transmontanus , is 

 a commercial and sport fish common to major river 

 systems of the Pacific Coast from Monterey, Calif., 

 to Alaska (Scott and Crossman 1973). However, 

 there is considerable confusion concerning migra- 

 tion habits or seasonal movements of the species. 

 Early workers (Jordan and Evermann 1908; Craig 

 and Hacker 1940) considered white sturgeon 

 anadromous. In free-flowing rivers, white stur- 

 geon move upstream in spring prior to spavining 

 (Carl et al. 1967; Bell 1973). Other investigators 

 (Bajkov 1951) suggested seasonal movements in 

 the lower Columbia River may be related to feed- 

 ing. 



Although some white sturgeon can be found in 

 the ocean and may ascend rivers to spawn, the 

 species is not truly anadromous. Many individuals 

 remain in freshwater, and those found in the upper 

 Columbia River and its tributaries are landlocked 

 by a system of hydroelectric dams. However, per- 

 manent freshwater residents also show seasonal 

 movements. Studies in 1975 and 1976, involving 

 radio-tagged white sturgeon in the mid-Columbia 

 River, indicated sturgeon movements >2 km oc- 

 curred when river temperatures exceeded 

 13° C (Haynes et al. 1978). Furthermore, size and 

 possibly sexual maturity influenced direction of 

 movement in the river. Smaller white sturgeon 

 moved downstream in summer, larger sturgeon 

 moved upstream in summer and fall, and inter- 

 mediate-sized sturgeon remained near release 

 points. Although seasonal movements may be re- 

 lated to water temperature, no quantitative data 

 exist on diel activity patterns of the species. To 

 further evaluate seasonal movements in the free- 

 flowing Hanford reach of the Columbia River, we 

 fitted additional white sturgeon with radio trans- 

 mitters in spring and early summer 1977 and con- 



tinued monitoring fish which had been tagged in 

 1975 and 1976. 



Methods 



Radio-telemetry equipment was developed by 

 the University of Minnesota, Bioelectronics 

 Laboratory (Tester and Siniff). Nineteen white 

 sturgeon ranging from 98 to 236 cm total length 

 were captured with trammel nets and angling 

 gear at White Bluffs Pool (Figure 1), about 48 km 

 upstream from Richland, Wash. Transmitters 

 were selected so as not to exceed 2^^( of estimated 

 sturgeon body weight and were attached dorsally 

 (Haynes et al. 1978). Twelve transmitters had tem- 

 perature sensors (precision ±0.2° C, Kuechle^). 

 An automatic, channel-scanning receiver and re- 

 cording station, capable of sequentially monitor- 

 ing 16 channels, was established at White Bluffs 

 Pool to record environmental temperatures and 

 sturgeon movements in and out of the pool. Re- 

 ceivers operated on a carrier frequency of 53 MHz 



'Tester, J. R., and D. B. Siniff. 1976. Vertebrate behavior 

 and ecology progress report for period July 1, 1975-June30,1976. 

 COO-1.332-123. Prepared for U.S. Energy Research and Devel- 

 opment Administration. Contract No. E(ll-1)-1332 by Univ 

 Minn., Minneapolis, 63 p. 



^V. B. Kuechle, Bioelectronics Laboratory at Cedar Creek, 

 University of Minnesota, Minneapolis, pers. commun. 1977. 



Figure l. — White Bluffs monitoring area for white sturgeon 

 movements in the Columbia River. 



FISHERY BULLETIN: VOL. 79, NO. 2, 198L 



367 



