Salmon fishermen will get an additional two days of spring Chinook fishing in the Columbia River upstream of Bonneville Dam.  Fishery managers Thursday extended the current spring Chinook season through Sunday after reviewing catch to-date indicating an estimated 300 upriver fish remain on the harvest guideline for the Columbia above Bonneville.  The extension applies to both bank and boat fishing from the Tower Island power lines about six miles below The Dalles Dam upstream to the Oregon/Washington border, plus bank fishing only between Bonneville Dam and the Tower Island power lines.  The daily bag limit remains two adipose fin-clipped adult salmon or steelhead in combination, of which no more than one may be a Chinook.  All other permanent regulations apply.