Abstract. — Spawning and early 

 life history of white sturgeon, Aci- 

 penser transmontanus, were stud- 

 ied in the lower Columbia River 

 downstream from Bonneville Dam 

 from 1988 through 1991. From 

 white sturgeon egg collections, we 

 determined that successful spawn- 

 ing occurred in all four years and 

 that the estimated spawning period 

 each year ranged from 38 to 48 

 days. The spawning period ex- 

 tended from late April or early May 

 through late June or early July of 

 each year. Spawning occurred pri- 

 marily in the fast-flowing section 

 of the river downstream from 

 Bonneville Dam, at water tempera- 

 tures ranging from 10 to 19C 

 Freshly fertilized white sturgeon 

 eggs were collected at turbidities 

 ranging from 2.2 to 11.5 nephelo- 

 metric turbidity units (ntu), near- 

 bottom velocities ranging from 0.6 to 

 2.4 m/s, mean water column veloci- 

 ties ranging from 1.0 to 2.8 m/s, 

 and depths ranging from 3 to 23 m. 

 Bottom substrate in the river sec- 

 tion where freshly fertilized eggs 

 were most abundant was primarily 

 cobble and boulder. White sturgeon 

 larvae were collected from river 

 kilometer (rkm) 45 to rkm 232, sug- 

 gesting wide dispersal after hatch- 

 ing. Larvae were collected as far 

 downstream as the upper end of the 

 Columbia River estuary, which is 

 a freshwater environment. Young- 

 of-the-year (YOY) white sturgeon 

 were first captured in late June, 

 less than two months after spawn- 

 ing was estimated to have begun. 

 Growth was rapid during the first 

 summer; YOY white sturgeon 

 reached a minimum mean total 

 length of 176 mm and a minimum 

 mean weight of 30 g by the end of 

 September. Young-of-the-year 

 white sturgeon were more abun- 

 dant in deeper water (mean mini- 

 mum depth >12.5 m) of the lower 

 Columbia River. The results indi- 

 cate that a large area of the lower 

 Columbia River is used by white 

 sturgeon at different life history 

 stages. 



Spawning and early life history 

 of white sturgeon, 

 Acipenser transmontanus, 

 in the lower Columbia River 



George T. McCabe Jr. 



Coastal Zone and Estuanne Studies Division, Northwest Fisheries Science Center 



National Marine Fisheries Service. NOAA 



2725 Montlake Blvd. East. Seattle. Washington 981 12-2097 



Charles A. Tracy 



Columbia River Fisheries Laboratory, Washington Department of Fish and Wildlife 

 RO. Box 999. Battle Ground. Washington 98604 



Manuscript accepted 28 February 1994. 

 Fishery Bulletin 92:760-772. 



White sturgeon, Acipenser trans- 

 montanus, is the largest of all North 

 American sturgeon species and is 

 found along the west coast of North 

 America from the Aleutian Islands, 

 Alaska, to Monterey, California 

 (Scott and Crossman, 1973). Al- 

 though this species is generally 

 anadromous (Scott and Crossman, 

 1973), some populations in the Co- 

 lumbia River Basin are landlocked 

 because of dam construction or 

 natural barriers (Cochnauer et al., 

 1985; Beamesderfer et al. 1 ). 



Historically, white sturgeon were 

 abundant in the Columbia River 

 (Oregon and Washington ) and in the 

 late 1800's supported an intense 

 commercial fishery. Commercial 

 catches peaked in 1892, when more 

 than 2.4 million kg were landed 

 (Craig and Hacker, 1940). After 

 1892, catches declined, and by 1899 

 the annual catch was less than 

 33,250 kg. Annual catches during 

 the early 1900's were less than 

 104,930 kg (Craig and Hacker, 1940). 



White sturgeon populations in 

 the Columbia River, particularly the 

 one downstream from Bonneville 

 Dam (the lowest dam at river kilo- 

 meter [rkm] 234), have recovered 

 sufficiently from the overfishing to 

 support important recreational and 

 commercial fisheries. The popula- 

 tion of white sturgeon in the lower 



Columbia River, which extends 

 from the mouth of the river to 

 Bonneville Dam, is one of the larg- 

 est in the world. From 1984 through 

 1988, the combined recreational 

 and commercial catch in this area 

 was at least 50,000 fish annually 

 (Wash. Dep. Fisheries and Oregon 

 Dep. Fish and Wildlife 2 ). During 

 1992, estimated catches of white 

 sturgeon for recreational and com- 

 mercial fisheries were 40,100 and 

 6,200 fish, respectively (Melcher 

 and King 3 ). Presently, white stur- 

 geon is the principal recreational 

 fish in the Columbia River down- 

 stream from Bonneville Dam (Mel- 

 cher and King 3 ). 



1 Beamesderfer, R. C, T. A. Rien. C. A. Fos- 

 ter, and A. L. Ashenfelter. 1990. Report A. 

 In A. A. Nigro (ed. ), Status and habitat re- 

 quirements of white sturgeon populations 

 in the Columbia River downstream from 

 McNary Dam, p. 6-37. Ann. Rep. to 

 Bonneville Power Admin. (Project 86-50) 

 by Oreg. Dep. Fish Wildl., Wash. Dep. Fish.. 

 Natl. Mar. Fish. Serv., and U.S. Fish Wildl. 

 Serv. Avail Bonneville Power Admin., P.O. 

 Box 3621, Portland, OR 97208. 



2 Washington Department of Fisheries and 

 Oregon Department of Fish and Wildlife. 

 1992. Status report — Columbia River fish 

 runs and fisheries, 1938-91, 224 p. Avail. 

 Wash. Dep. Fish., P.O. Box 999, Battle 

 Ground, WA 98604. 



1 Melcher, C E., and S. D. King. 1993. The 

 1992 lower Columbia River and Buoy 10 

 recreational fisheries, 77 p. Oregon Dep. 

 Fish Wildl., 17330 S.E. Evelyn St., 

 Clackamas, OR 97015. 



760 



