|Document Type:||Chapter or Section|
|Type of Book:||Technical|
|Section or Chapter Title:||Spawning characteristics and early life history of white sturgeon Acipenser transmontanus in the Lower Columbia River|
|Book Title:||Status & habitat requirements of the white sturgeon populations in the Columbia River downstream from McNary Dam: Volume I|
|Author:||George T. McCabe, Charles A. Tracy|
|Editor:||Raymond C. Beamesderfer, Anthony A. Nigro (Eds.)|
|Publisher:||Report of the National Marine Fisheries Service and Washington Department of Fisheries to the Bonneville Power Administration. Portland, Oregon|
Although white sturgeon Acipenser transmontanus experiences intense fishing pressure in the Columbia River (Oregon and Washington) and other rivers within its range, little is known about the spawning characteristics and early life history of this long-lived species. Spawning characteristics and early life history of white sturgeon were studied in the lower Columbia River downstream from Bonneville Dam from 1988 through 1991. Based on white sturgeon egg collections, we determined that successful spawning occurred in all four years; the estimated number of spawning days each year ranged from 38 to 47 d. The spawning period extended from late April or early May through late June or early July of each year. Spawning occurred primarily in the fast-flowing section of the river downstream from Bonneville Dam at water temperatures ranging from 10 to 19°C. Freshly fertilized white sturgeon eggs were collected at turbidities ranging from 2.2 to 11.5 NTU, near-bottom velocities ranging from 0.6 to 2.4 m/s, mean water column velocities ranging from 1.0 to 2.8 m/s, and depths ranging from 3 to 23 m. Bottom substrate in the spawning area was primarily cobble and boulder.
With the exception of 1989, there were no significant regression relationships between white sturgeon egg catches at an index site and water velocity or Bonneville Dam discharge during the spawning period. Apparently, adequate water velocities for white sturgeon spawning were generally present throughout the spring and early summer. White sturgeon larvae were dispersed over a wide area (in some instances over 175 km) after hatching; 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 2 months after spawning was estimated to have begun. Growth was rapid during the first summer, with YOY white sturgeon reaching a minimum mean total length of 176 mm and a minimum mean weight of 30 g by the end of September. YOY white sturgeon were more abundant in deeper water (mean minimum depth ≥ 12.5 m) of the lower Columbia River. This research indicated that a large area of the lower Columbia River is used by white sturgeon at different life history stages.
|Notes:||George T. McCabe Jr. also coauthored sections C (pp. 61-79) and I (pp. 207-230) of this report.|