| Abstract/Description or Keywords |
The Nechako was sampled using gillnets, cod traps, angling and beach seining from September 3 –October 2, 2008 for the purposes of capturing white sturgeon under 1metre total length (TL). Monitoring for acoustic tags was carried out from June to September. Sampling was focused from slightly upstream of Vanderhoof downstream to the confluence of the Stuart River. Efforts in 2008 were a continuation of focused juvenile white sturgeon sampling programs conducted annually since 2004. The intent of these sampling programs is to gather information about the status of juvenile white sturgeon recruitment into the Nechako’s population, and provide insight into factors affecting their survival. Additionally, these sampling efforts are developing information to inform the format of a standardized, longterm “index type”program that will be required to monitor juvenile sturgeon recruitment into the Nechako’s population onan ongoing basis. Monitoring the success or failure of recovery actions, relative to their goal of improving the rate of juvenile recruitment into the population, including monitoring the survival, health and distribution of hatchery-reared juveniles, is a key component of the Recovery Strategy for the Nechako’s whitesturgeon population. A total of 164 panel-hours of gillnetting effort were applied (37.3m2 panels), 8470 hours of cod trapping effort, 15 hours of angling and 10 sets of beach seining over three days were applied throughout the sampling period. No sturgeon were caught via codtraps, angling or beach seining. A total of 29 hatchery reared juvenile white sturgeon were tagged with acoustic tags in the fall of 2007, just prior to their release in October/November. Their tags were programmed to begin signalling in May of 2008. CSTC staff completed a total of 15 days of acoustic monitoring between June and September 2008. Six of the 29 tags were detected. They were located in the Nechako River at km 110km, 116km, 117km, and 117.4km. A total of five white sturgeon were captured via gillnetting. All were captured between river km 110.1 and 116.1, in association with deep water habitats and known overwintering sites at 110km, 114km and 116km. The largest (103cm TL) of the five sturgeon captured was aged at 13 years. The smallest (34.0cm TL) was aged at 2 years. The sturgeon were caught in depths between 3.0 –10.0m. One capture was a hatchery reared juvenile released in 2006 (PIT tag 4849044462). A total of 1,125 other fish were bi-captured during the sampling program, including 53 sport fish. A total of 1,054 of the bi-captured fish were released successfully, and 71 were recorded as mortalities, including three sport fish. A “splash cam” underwater camera wasused for four days in October for the purposes of documenting any congregations of sturgeon, particularly hatchery juveniles, that may be observable. The camera was used in the Nechako river from 109km-116km and at the 125km over-wintering hole. Sturgeon were observed, but the larger congregations of fish that had been previously recorded could not be found |
