Continued improvement in the number of upriver spring Chinook salmon returning to the Columbia River prompted fishery managers from Oregon and Washington to reopen the recreational fishing season above Bonneville Dam.  Spring Chinook fishing will reopen above Bonneville Dam from Saturday through June 15 under rules adopted during a joint state hearing of fish and wildlife officials from the two states.  The joint state action is based on a revised estimate of salmon returns issued Tuesday adjusting the expected return of upriver Chinook to 230,000 fish, up from the previous estimate of a minimum 224,000 upriver fish.  The season will open to both boat and bank fishing from the Tower Island power lines approximately six miles below The Dalles Dam, upstream to the Oregon/Washington border, plus bank fishing only from Bonneville Dam to the Tower Island power lines.  The bag limit is two fin-clipped adult salmonids per day, of which only one may be a Chinook.  Up to five adipose fin-clipped jack Chinook and shad may also be kept per permanent regulations.