| Abstract/Description or Keywords |
The Nechako River population of white sturgeon (Acipenser transmontanus) is ranked as a critically imperilled species in British Columbia (BC Conservation Data Centre 2006), as well as a species listed as endangered on Schedule 1 of the Species at Risk Act (SARA). Genetic analysis indicates that the Nechako River population is distinct from that of the Fraser River, suggesting that there is no or limited inter-breeding between the populations (Smith et al. 2002). Research also suggests that the Nechako population is experiencing recruitment failure, with the population dominated by larger and older fish with few juveniles (Nechako White Sturgeon Recovery Initiative (NWSRI) 2004). At present the reasons for the recruitment failure is unknown. Extensive radio tagging programs has allowed for the tracking of adult white sturgeon movements in the Nechako River. In recent years, Golder Associates (2006) completed a tagging program in the fall of 2005 in which 27 sturgeon were implanted with internal radio transmitters. In the spring of 2006 (concurrent to the monitoring project reported here) a study was initiated by the Nechako/Upper Fraser White Sturgeon Technical Working Group (NUF-TWG), to capture brood stock, and subsequently incubate, hatch and raise juvenile sturgeon for release in order to meet the goals of the breeding plan (NWSRI 2005). A total of two ripe females and four mature males were removed from the Nechako River during the 2006 spawning period and held at a facility in Prince George, and numerous other fish were implanted with radio transmitters. This effort, in addition to previous work by Golder and Associates, the BC Ministry of Environment, and the Carrier Sekani Tribal Council (CSTC), brought the total number of active tags in adult fish to approximately 70 by the fall of 2006. Radio tagging efforts, and work completed by Triton Environmental Consultants Ltd. (Triton) in 2004 and 2005 formed the basis for the monitoring and sampling plan for 2006. In particular, a previously identified spawning area in the vicinity of Vanderhoof (Triton 2004) was the focus for the work in 2006. In addition, the physical conditions in the river around the time of the congregation in 2004 (i.e. water temperature and discharge) were examined to identify the critical monitoring period for 2006. Using the information on timing and location of the 2004 congregation (no congregation was detected in 2005), the 2006 Nechako white sturgeon spawning assessment project was initiated in order to monitor Nechako River white sturgeon during the expected period of spawning activity (mid-May to mid-June), and to complete field surveys should a congregation of sturgeon be observed (Alan Primary Metal 2006). This report outlines the methods used to monitor white sturgeon spawning in the Nechako River in 2006, presents the results of field activities undertaken in May and June of 2006, and details a preliminary model that assesses the ability of a suite of environmental cues to predict the timing of white sturgeon spawning in the Nechako River. |
