2012 Thompson and Chilcotin Steelhead Update
Posted on October 5th 2012, by Robert Bison, BC Fisheries Stock Assessment Biologist
From September 1st to date, five steelhead have been caught in the Albion test fisheries, all of which have been caught in the chum test fishery. None have been caught in the chinook test fishery (Figure 1).
Figure 1. Observed catches of steelhead in the Albion chum and chinook test fisheries to date, illustrated by the diamonds and squares, respectively. The lines illustrate the "average" pattern expected for the balance of the season, given the observed catches to date, the historical data on run timing and the historical data on the efficiency of the two gillnets.
Presently, the test fishing data suggest that there is a 15% chance of exceeding the abundance reference point of 1250 Thompson and Chilcotin steelhead. This reference abundance is identified in the 2012 Integrated Fisheries Management Plan for the management of Fraser River commercial chum fisheries. For the Thompson watershed alone, there is presently a 20% chance of exceeding the abundance reference point of 850, the reference point used to open or close the catch-and-release sport fishery.
At this point, the estimated abundance is lower than expected given the recent stock productivity patterns and trends. The estimate suggests that productivity is not improving as has been recently observed in some other BC steelhead stocks. The abundance estimate suggests that the 2012/13 return might be among the lowest ever observed. In the Thompson, the lowest spawner abundance observed to date is 500, observed in the spring of 2011. In the Chilcotin, the lowest spawner abundance observed to date is 140, observed in the spring of 2010 (Figures 2 & 3).
Figure 2. Trends in the estimated pre-fishery abundance (squares) and spawning abundance (diamonds) of Thompson River Steelhead.
Figure 3. Trends in the estimated pre-fishery abundance (squares) and spawning abundance (diamonds) of Chilcotin River Steelhead.
Sport fisheries on Interior Fraser steelhead were closed on October 1st and may open later in the month if the abundance forecast exceeds conservation limits.
Further updates will be provided as the season progresses.
Fisheries Stock Assessment Biologist
Fish & Wildlife Branch