A recently released study on winter-run chinook salmon adds a new wrinkle to efforts to conserve the fish, which have had a larger influence on statewide water policy during California’s drought. As water supplies dwindled during the drought, state and federal officials found it increasingly difficult to protect the endangered salmon’s eggs and recent hatches, which need colder water to survive in the Sacramento River. Water agencies from Redding to Southern California saw their supplies reduced as federal and state officials tried to manage water temperatures in the river to benefit the salmon.