| Abstract/Description or Keywords |
The Nechako River supports a small population of white sturgeon genetically distinct from other sturgeon populations within the Fraser River watershed. The Nechako white sturgeon is provincially ranked as a “red-listed” population and is federally designated as an “endangered” species under Schedule 1 of the Species At Risk Act. A multi-year sampling program was initiated in 2004, and continued annually until 2009, with the intent to gather data regarding juvenile Nechako white sturgeon; ultimately this program will lead to the development of a standardized long-term indexing program to monitor juvenile recruitment. The utility of various sampling techniques, such as gillnets, cod traps, beach seines and angling, were investigated between 2004 and 2008 after which it was suggested that alternative captured techniques be investigated. The Nechako River was sampled for juvenile sturgeon between August 24 and October 6, 2009. Sampling was focused towards areas of known sturgeon rearing/overwintering habitat between river kilometres 110 and 135. Set-lines and angling were the primary sampling techniques, resulting in 10,015.37 hook-hours and 123.93 rod-hours of effort, respectively and the total capture of 20 white sturgeon. Nine sturgeon, all juveniles, were captured on set-lines. Eleven sturgeon, six juveniles, two sub-adults and three adults were captured on angling gear. Gillnets and seine nets were also employed as capture techniques, resulting in 43.78 panel-hours and 50 minutes of net effort, respectively. No sturgeon were captured using either of these techniques. A total of 15 juvenile white sturgeon between 29.6 and 99.3cm fork length were captured, of which seven were recaptures. One of these recaptures was a hatchery raised fish from 2008 fitted with a sonic tag and released in June, 2009. A total of 227 other fish were incidentally captured. Juveniles were captured in areas in proximity of known over-wintering sites near river kilometres 110 and 117. Evidence from this assessment suggests that set-lines and angling are effective methods of juvenile sturgeon capture and should be incorporated into future monitoring activities. |
